ORCID Profile
0000-0002-1521-2423
Current Organisation
Macquarie University
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Lasers and Quantum Electronics | Photonics and Electro-Optical Engineering (excl. Communications) | Optical Physics | Electrical and Electronic Engineering | Nanotechnology | Photonics, Optoelectronics and Optical Communications | Nonlinear Optics and Spectroscopy | Engineering And Technology Not Elsewhere Classified | Optical Properties of Materials | Nanomanufacturing | Nanomaterials | Interdisciplinary Engineering Not Elsewhere Classified | Interdisciplinary Engineering | Condensed Matter Modelling and Density Functional Theory | Optics And Opto-Electronic Physics | Astronomical and Space Instrumentation | Nanofabrication, Growth and Self Assembly
Expanding Knowledge in the Physical Sciences | Scientific Instruments | Expanding Knowledge in Technology | Environmental Management Systems | Emerging Defence Technologies | Medical instrumentation | Scientific instrumentation | Other | Satellite Communication Networks and Services | Industrial Instruments | Expanding Knowledge in Engineering |
Publisher: American Physical Society (APS)
Date: 15-05-2014
Publisher: Elsevier BV
Date: 10-1995
Publisher: The Optical Society
Date: 04-06-2019
DOI: 10.1364/OE.27.017209
Publisher: The Optical Society
Date: 28-11-2018
DOI: 10.1364/OE.26.032717
Publisher: Wiley
Date: 28-03-2013
Publisher: AIP Publishing
Date: 09-2006
DOI: 10.1063/1.2338284
Abstract: A method for addressing in idual laser pulses in high repetition frequency systems using an intracavity optical chopper and novel electronic timing system is reported. This “pulse on command” capability is shown to enable free running and both subharmonic pulse rate and burst mode operation of a high power, high pulse frequency copper vapor laser while maintaining a fixed output pulse energy. We demonstrate that this technique can be used to improve feature finish when laser micromachining metal.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 1998
DOI: 10.1109/3.736089
Publisher: IEEE
Date: 2003
Publisher: Optica Publishing Group
Date: 15-07-2005
DOI: 10.1364/OL.30.001829
Publisher: Optica Publishing Group
Date: 04-2008
DOI: 10.1364/OE.16.005277
Abstract: We present a detailed experimental and modeling study of fiber lasers passively mode locked using stimulated Raman scattering. We present experimental measurements of the mode locking behavior, and use the model to elucidate the nonlinear processes that create the intracavity pulses and determine the repetition rate and the order of fundamental and Raman pulses. We also present a simple method for harmonic mode locking Raman fiber lasers.
Publisher: AIP Publishing
Date: 31-07-2023
DOI: 10.1063/5.0159079
Abstract: Free-space Brillouin lasers (BLs) generate high-power narrow-linewidth laser outputs at specific wavelengths. However, despite these impressive results, further compressing the Stokes linewidth while maintaining a high-power output remains a challenge. This study was conducted to investigate the design of BLs, starting from the phase-matching conditions and stability of a Brillouin cavity, for media with different phonon frequencies. A high-power and narrow-linewidth output can be realized using large-size, wide-gain-bandwidth Brillouin media. We experimentally demonstrated a BL using fused silica and diamond with the same cavity parameters. Stokes powers of 21.6 and 18.9 W were obtained with fused silica and diamond, respectively, at an available pump power of 58 W. Using fused silica, a Stokes linewidth of 1.2 kHz was obtained, which is two times narrower than that obtained using the diamond BL. Such BL design routes for various Brillouin media provide a path for achieving high-power, ultra-narrow-linewidth laser radiation at specific wavelengths.
Publisher: Springer Netherlands
Date: 1996
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2000
DOI: 10.1109/3.880654
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2018
Publisher: AIP Publishing
Date: 02-05-2022
DOI: 10.1063/5.0087092
Abstract: Cascaded Brillouin lasers based on guided-wave structures are applied across a range of important fields such as optical communications, microwave photonics, and sensing. However, restricted by the volume and available transmission range of the gain medium, the power output and wavelength ersity of guided-wave Brillouin devices are somewhat limited. In this work, we report the design and development of a cascaded Brillouin laser based utilizing a free-space optical layout with a diamond crystal as the Brillouin gain medium. A quasi-continuous-wave, 1 μm laser was used as the pump laser, and Raman wavelength conversion is used as an intermediate process to facilitate stimulated Brillouin scattering with a low threshold. When the output transmission of the diamond cavity is 0.37% and the incident pump power is 220 W, cascading of the Brillouin–Stokes field to the eighth Stokes and the seventh anti-Stokes orders was observed. By adjusting the cavity length, the order of the cascaded Brillouin laser output is controlled. A comprehensive analysis of the Brillouin generation process and the cascade of Stokes orders is undertaken for different incident pump powers and cavity lengths. This work is expected to enable practical applications of high-power Brillouin lasers and Brillouin frequency combs.
Publisher: SPIE
Date: 28-01-2005
DOI: 10.1117/12.576242
Publisher: The Optical Society
Date: 30-06-2014
DOI: 10.1364/OL.39.004037
Publisher: OSA
Date: 2018
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2011
Publisher: Optica Publishing Group
Date: 20-12-2023
DOI: 10.1364/OE.472185
Abstract: Thermo-optic actuators based on bulk materials are considered too slow in applications such as laser frequency control. The availability of high-quality optical materials that have extremely fast thermal response times, such as diamond, present an opportunity for increasing performance. Here, diamond thermal actuators are investigated for configurations that use a planar thermal resistive layer applied to a heat-sinked rectangular prism. A general analytical formulation is obtained which simplifies substantially for high thermal conductivity such as diamond. Expressions for modulation depth, bandwidth and power requirements are obtained as functions of modulator dimensions and heat-transfer coefficients. For a 1 mm × 1 mm cross-section diamond at wavelength of 1 μ m, around 450 W of applied heat power is needed to achieve a π phase shift at a modulation frequency of 2 kHz.
Publisher: OSA
Date: 2004
Publisher: The Optical Society
Date: 15-03-2019
Publisher: OSA
Date: 2010
Publisher: The Optical Society
Date: 02-08-2016
Publisher: The Optical Society
Date: 04-02-2014
DOI: 10.1364/OE.22.003325
Publisher: Optica Publishing Group
Date: 2004
Abstract: We report efficient operation of a KGd(WO(4))(2) Raman laser pumped by a small, 1 W, 532 nm laser module. By changing the output coupler and Raman crystal orientation, more than 8 wavelengths in the yellow-to-red spectral region were generated including 555 nm, 559 nm, 579 nm, 589 nm, 606 nm, 622 nm, 636 nm and 658 nm, ie., the first 4 Stokes orders on the two orthogonal high-gain Raman shifts of KGd(WO(4))(2). We have also demonstrated spectrally pure output (typically >90% pure) for selected Stokes order with output power up to 400 mW. High slope efficiency (up to 68%) and high beam quality (M(2)~1.5) of Stokes output are obtained even at the highest pump power.
Publisher: Wiley
Date: 28-03-2013
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2003
Publisher: Optica Publishing Group
Date: 09-01-2009
DOI: 10.1364/OE.17.000810
Abstract: We report a parametric anti-Stokes Raman laser using potassium gadolinium tungstate, generating output chiefly at the first anti-Stokes at 508 nm. The compact 4.5 cm long device is pumped by a Q-switched 532 nm laser and uses an off-axis Stokes resonator to provide non-collinear phase matching between the pump and the generated Stokes and anti-Stokes fields. Anti-Stokes output energies up 0.27 mJ were obtained at a conversion efficiency from the pump of 0.46%. Second- and third-order anti-Stokes lines at 486 nm and 465 nm were also observed.
Publisher: Wiley
Date: 30-03-2017
Publisher: The Optical Society
Date: 03-11-2011
DOI: 10.1364/OE.19.023554
Publisher: Elsevier BV
Date: 05-1997
Publisher: Optica Publishing Group
Date: 22-02-2023
DOI: 10.1364/OE.483482
Abstract: We report an investigation into secondary mode suppression in single longitudinal mode (SLM) 1240 nm diamond Raman lasers. For a three-mirror V-shape standing-wave cavity incorporating an intra-cavity LBO crystal to suppress secondary modes, we achieved stable SLM output with a maximum output power of 11.7 W and a slope efficiency 34.9%. We quantify the level of χ (2) coupling necessary to suppress secondary modes including those generated by stimulated Brillouin scattering (SBS). It is found that SBS-generated modes often coincide with higher-order spatial modes in the beam profile and can be suppressed using an intracavity aperture. Using numerical calculations, it is shown that the probability for such higher-order spatial modes is higher for an apertureless V-cavity than in two-mirror cavities due its contrasting longitudinal mode-structure.
Publisher: AIP Publishing
Date: 08-2023
DOI: 10.1063/5.0155283
Abstract: The cascade operation of Brillouin lasers (BLs) is an identified obstacle to single-frequency power scaling and further compression of the fundamental linewidth. In this study, we reveal the relationship between the maximum cascade order and system parameters, starting from the phase-matching conditions of the Stokes cascade. The second Stokes is suppressed for modes that fall away the Brillouin gain linewidth (ΓB), which is heightened for Brillouin gain media with high sound velocity, large refractive index, and narrow linewidth. Diamond, with its extremely high product of speed of sound and refractive index, satisfies these requirements and is found to achieve cascade-free intramode scattering (TEM00) without manipulating cavity mode structures. This study elucidates a route to single-frequency, narrow-linewidth BLs via Brillouin material selection.
Publisher: Springer Science and Business Media LLC
Date: 2012
DOI: 10.1557/OPL.2012.327
Abstract: In its relatively short history as a Raman laser material, CVD diamond has already demonstrated to be a forerunner in performance. Yet the more outstanding properties of the material such as its high thermal conductivity and wide transmission range remain largely unexploited. This paper summarizes the recent studies aimed to extend diamond laser capability beyond that readily achievable using other materials, focusing on in particular diamond Raman lasers in the ultraviolet, infrared and at high average powers.
Publisher: AIP Publishing
Date: 03-2020
DOI: 10.1063/1.5134907
Abstract: Brillouin lasers providing extremely narrow-linewidth are emerging as a powerful tool for microwave photonics, coherent communications, quantum processors, and spectroscopy. So far, laser performance and applications have been investigated for a handful of select materials and using guided-wave structures such as micro-resonators, optical fibers, and chip-based waveguides. Here, we report a Brillouin laser based on free-space laser action in an extreme optical material. Continuous-wave lasing 167 GHz from a 532 nm pump is demonstrated in diamond using a doubly resonant ring cavity, generating a pump-limited output power of 11 W. The Brillouin gain coefficient is measured to be 79 cm GW−1 with a linewidth of 12 MHz. These properties, along with an exceptionally high Brillouin frequency and wide transmission range, make diamond Brillouin lasers a promising high-power source of narrow-linewidth output and mm-wave beat notes.
Publisher: Optica Publishing Group
Date: 2008
DOI: 10.1364/OE.16.003261
Abstract: We report increased wavelength options from Raman lasers for Raman media having two Raman modes of similar gain coefficient. For an external-cavity potassium gadolinium tungstate Raman laser pumped at 532 nm, we show that two sets of Stokes orders are generated simultaneously by appropriate orientation of the Raman crystal, and also wavelengths that correspond to sums of the two Raman modes. Up to 14 visible Stokes lines were observed in the wavelength range 555-675 nm. The increase in Stokes wavelengths also enables a much greater selection of wavelengths to be accessed via intracavity nonlinear sum frequency and difference frequency mixing. For ex le, we demonstrate 30 output wavelength options for a wavelength-selectable 271-321 nm Raman laser with intracavity sum frequency mixing in BBO. We also present a theoretical analysis that enables prediction of wavelength options for dual Raman mode systems.
Publisher: The Optical Society
Date: 18-01-2018
DOI: 10.1364/OE.26.001930
Publisher: IOP Publishing
Date: 02-11-2022
Abstract: We demonstrate a high-efficiency continuous-wave (CW) diamond Raman laser operating at 1178 nm with enhanced stability by using a V-cavity design. A maximum Stokes power of 39 W with a conversion efficiency of 45% was achieved using a linearly-polarized 1018 nm Yb-doped fiber pump laser. The Stokes CW power stability showed superior stability over a linear cavity when characterized over periods up to 15 min. The Stokes output was found to switch between linear, elliptical, and random polarization with varying pump polarization. The results represent a major step towards stable, efficient and high-power CW lasers at 1178 nm and at wavelengths outside the main Yb, and Nd emission bands.
Publisher: The Optical Society
Date: 18-11-2010
DOI: 10.1364/OL.35.003874
Publisher: MDPI AG
Date: 15-06-2021
DOI: 10.3390/NANO11061572
Abstract: Despite their extremely high thermal conductivity and low thermal expansion coefficients, thermal effects in diamond are still observed in high-power diamond Raman lasers, which proposes a challenge to their power scaling. Here, the dynamics of temperature gradient and stress distribution in the diamond are numerically simulated under different pump conditions. With a pump radius of 100 μm and an absorption power of up to 200 W (corresponding to the output power in kilowatt level), the establishment period of thermal steady-state in a millimeter diamond is only 50 μs, with the overall thermal-induced deformation of the diamond being less than 2.5 μm. The relationship between the deformation of diamond and the stability of the Raman cavity is also studied. These results provide a method to better optimize the diamond Raman laser performance at output powers up to kilowatt-level.
Publisher: OSA
Date: 2018
Publisher: The Optical Society
Date: 10-01-2017
DOI: 10.1364/OE.25.000749
Publisher: SPIE
Date: 13-01-2017
DOI: 10.1117/12.2261684
Publisher: OSA
Date: 2015
Publisher: The Optical Society
Date: 12-02-2016
Publisher: SPIE
Date: 30-12-2019
DOI: 10.1117/12.2539013
Publisher: Optica Publishing Group
Date: 11-01-2023
DOI: 10.1364/OE.476759
Abstract: Free-space Brillouin lasers (BLs) are capable of generating high-power, narrow-linewidth laser outputs at specific wavelengths. Although there have been impressive experimental demonstrations of these lasers, there is an absence of a corresponding theory that describes the dynamic processes that occur within them. This paper presents a time-independent analytical model that describes the generation of the first-order Stokes field within free-space BLs. This model is based on the cavity resonance enhancement theory and coupled wave equations that govern the processes of stimulated Brillouin scattering (SBS). This model is validated using an experimental diamond BL to numerically simulate the influence of the cavity design parameters on the SBS threshold, pump enhancement characteristics, and power of the generated Stokes field. Specifically, the model is used to determine the SBS cavity coupler reflectance to yield the maximum Stokes field output power and efficiency, which is also a function of the pump power and other cavity design parameters. This analysis shows that the appropriate choice of Brillouin cavity coupler reflectance maximizes the Stokes field output power for a given pump power. Furthermore, the onset of higher-order Stokes fields that are undesirable in the context of single-frequency laser operation were inhibited. This study aids in understanding the relationship between the cavity parameters and resultant laser characteristics for the design and optimization of laser systems.
Publisher: SPIE
Date: 28-02-2014
DOI: 10.1117/12.2037168
Publisher: Elsevier BV
Date: 2008
Publisher: SPIE
Date: 24-04-2000
DOI: 10.1117/12.383467
Publisher: Springer Science and Business Media LLC
Date: 17-09-2008
Publisher: Optica Publishing Group
Date: 27-05-2021
DOI: 10.1364/OE.426067
Abstract: We present experimental results and modeling of continuous wave resonantly pumped Raman lasers. The first Stokes diamond Raman ring laser generated 0.6 W at 960 nm with an efficiency of 18% the second Stokes laser generated 1.5 W at 1485 nm at 9% efficiency. The analytical model, extended to arbitrary Stokes orders, shows the importance of modelling imperfect mode matching and guides the optimization of input and output coupler reflectivity to predict practical watt-level Raman converters of few-watt pump lasers.
Publisher: AIP Publishing
Date: 03-10-2022
DOI: 10.1063/5.0107200
Abstract: We demonstrate a continuous-wave single-frequency diamond Raman laser operating at 1178 nm by using a linear resonator that is stabilized using an intracavity χ(2) element. Optimization of the single-frequency power was realized by tuning the phase matching in the χ(2) element away from the second-harmonic peak to suppress neighboring modes via sum frequency generation but avoid large losses to the intracavity primary Stokes mode. A maximum single-longitudinal-mode power of 20 W at 1178 nm with an instrument-limited linewidth of 67 MHz was obtained using a 12 GHz multi-longitudinal-mode Yb-doped fiber pump laser at 1018 nm with power of 82 W. This work provides an interesting route for producing single-frequency high-power lasers near 1.2 μm utilizing diamond Raman conversion combined with broadband, high-power, low-cost YDF lasers.
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEOPR.2020.C7A_1
Abstract: For the first time, a 22 W continuous-wave sodium guide star laser is demonstrated in an external standing-wave diamond Raman resonator with intra-cavity second harmonic generation.
Publisher: IEEE
Date: 06-2019
Publisher: Optica Publishing Group
Date: 23-03-2022
DOI: 10.1364/OL.454450
Abstract: High-purity single-photon sources (SPS) that can operate at room temperature are highly desirable for a myriad of applications, including quantum photonics and quantum key distribution. In this work, we realize an ultra-bright solid-state SPS based on an atomic defect in hexagonal boron nitride (hBN) integrated with a solid immersion lens (SIL). The SIL increases the source efficiency by a factor of six, and the integrated system is capable of producing over ten million single photons per second at room temperature. Our results are promising for practical applications of SPS in quantum communication protocols.
Publisher: IEEE
Date: 06-2007
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2015
Publisher: IOP Publishing
Date: 20-08-2004
Publisher: IOP Publishing
Date: 21-09-2000
Publisher: SPIE
Date: 26-02-2018
DOI: 10.1117/12.2288213
Publisher: AIP Publishing
Date: 11-04-2022
DOI: 10.1063/5.0088592
Abstract: We report on the generation and tuning of single-frequency laser light in a monolithic Fabry–Pérot diamond Raman resonator operating in the visible spectral range. The device was capable of squeezing the linewidth of a broad multi-mode nanosecond pump laser (Δνp= 7.2 ± 0.9 GHz at λp= 450 nm) to a nearly Fourier-limited single axial mode Stokes pulse (ΔνS= 114 ± 20 MHz at λS= 479 nm). The tuning was achieved by precise adjustment of the resonator temperature, with a measured frequency-temperature tuning slope of ∂ν0/∂T≈ −3 GHz/K, and a temperature dependence of the first-order Raman phonon line of ∂νR/∂T≈ +0.23 GHz/K. The Stokes center frequency was tuned continuously for over 20 GHz (more than twice the free spectral range of the resonator), which, in combination with the broad Ti:Sapphire laser spectral tunability, enables the production of Fourier-limited pulses in the 400–500 nm spectral range. The Stokes center-frequency fluctuations were 52 MHz (RMS) when the temperature of the resonator was actively stabilized. Moreover, the conversion efficiency was up to 30%, yielding an overall power spectral density enhancement of & × from pump to Stokes pulse.
Publisher: Elsevier BV
Date: 2018
Publisher: Optica Publishing Group
Date: 17-03-2022
Abstract: Fourier-limited nanosecond pulses featuring narrow spectral bandwidths are required for applications in spectroscopy, sensing, and quantum optics. Here, we demonstrate a direct and simple route for the generation of single-frequency light relying on phonon-resonant Raman interactions within a monolithic diamond resonator. The technique enables the production of nearly Fourier-limited nanosecond optical pulses (15 ns), with an overall spectral bandwidth of down to 180 MHz, which is nearly two orders of magnitude narrower than the pump laser linewidth used (12 GHz). The power conversion efficiency was 47%, yielding a power spectral brightness enhancement of --> 50 × compared to the pump. Our results pave the way to the integration of pulsed widely tunable, power scalable, narrow linewidth light sources into integrated photonic platforms. Furthermore, the device does not need elaborate mechanical feedback loops for cavity length or frequency stabilization, or any additional optical components.
Publisher: IEEE
Date: 1998
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/ASSL.2020.ATU2A.5
Abstract: We study theoretically and experimentally the spectral and polarization effects occurring when cascading stimulated Raman scattering processes in diamond. We demonstrate an efficient, few-GHz linewidth, broadly tunable, multi-Stokes comb for spectroscopic applications.
Publisher: The Optical Society
Date: 06-08-2019
DOI: 10.1364/OL.44.003924
Publisher: IEEE
Date: 1998
Publisher: ACM
Date: 18-06-2023
Publisher: IEEE
Date: 1994
Publisher: IEEE
Date: 09-2010
Publisher: Wiley
Date: 10-03-2014
Publisher: WORLD SCIENTIFIC
Date: 2007
Publisher: IEEE
Date: 07-2017
Publisher: IOP Publishing
Date: 11-12-2002
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2005
Publisher: IEEE
Date: 2003
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEOPR.2020.C12A_2
Abstract: An investigation into UV two-photon etching of diamond surfaces in low pressure conditions is presented. A tenfold increase in etch rate was observed, attributed to the reduced role of water vapour in suppressing carbon ejection.
Publisher: Optica Publishing Group
Date: 03-11-2008
DOI: 10.1364/OE.16.018950
Abstract: Recent progress in diamond growth via chemical vapor deposition (CVD) has enabled the manufacture of single crystal s les of sufficient size and quality for realizing Raman laser devices. Here we report an external cavity CVD-diamond Raman laser pumped by a Q-switched 532 nm laser. In the investigated configuration, the dominant output coupling was by reflection loss at the diamond's uncoated Brewster angle facets caused by the crystal's inherent birefringence. Output pulses of wavelength 573 nm with a combined energy of 0.3 mJ were obtained with a slope efficiency of conversion of up to 22%.
Publisher: IEEE
Date: 08-2015
Publisher: American Physical Society (APS)
Date: 08-01-2019
Publisher: SPIE
Date: 15-02-2018
DOI: 10.1117/12.2287773
Publisher: IOP Publishing
Date: 23-09-2022
DOI: 10.35848/1882-0786/AC9177
Abstract: We propose a narrow-linewidth demodulation method which utilizes a short-fiber-delayed self-heterodyne structure and coherent envelope spectral properties to restore the Lorentzian line shape of the laser output. The Lorentzian spectrum obtained using our scheme is consistent with that obtained using a traditional long-delay method, and here, the utilization of a short fiber avoids the broadening caused by 1/f noise. Both simulated and experimental results demonstrate that our scheme is effective and accurate. We demonstrate the recovery of a Lorentzian linewidth of 6.0 kHz, while maintaining higher accuracy than that achieved using traditional schemes (31.7 kHz). Our approach provides a feasible means of improving the accuracy and computational efficiency of narrow linewidth measurements.
Publisher: The Optical Society
Date: 30-01-2018
DOI: 10.1364/OL.43.000563
Publisher: IEEE
Date: 1994
Publisher: Frontiers Media SA
Date: 16-08-2021
Abstract: A 7.8-GHz linewidth ytterbium-doped fiber (YDF) laser with an output power of 75 W at 1,018 nm is demonstrated based on narrow-bandwidth fiber Bragg gratings. Effective suppression of spectral broadening and lified spontaneous emission is achieved by optimizing the resonator structure and active fiber parameters. An 1,178-nm diamond Raman output pumped by this narrow-linewidth 1,018 nm source is addressed in this study, which shows a promising application of generating the sodium guide star laser at 589 nm. A single-longitudinal-mode Stokes with an output power of 0.6 W is obtained using this multimode 1,018 nm laser at the pump power of 13 W. The impact of pump spectral linewidth on the effective Raman gain coefficient is analyzed, and the laser threshold of the diamond Stokes resonator increases with the broadening of the pump linewidth.
Publisher: Springer Science and Business Media LLC
Date: 23-03-2014
DOI: 10.1007/S10103-013-1287-4
Abstract: Fungal infection of nails, onychomycosis, is predominantly caused by Trichophyton rubrum. This infection is an important public health concern due to its persistent nature and high recurrence rates. Alternative treatments are urgently required. One such alternative is phototherapy involving the action of photothermal or photochemical processes. The aim of this novel study was to assess which wavelengths within the ultraviolet (UV) spectrum were inhibitory and equally important nail transmissible. Initial irradiations of T. rubrum spore suspensions were carried out using a tunable wavelength l system (fluence ≤3.1 J/cm(2)) at wavelengths between 280 and 400 nm (UVC to UVA) to evaluate which wavelengths prevented fungal growth. Light-emitting diodes (LEDs) of defined wavelengths were subsequently chosen with a view to evaluate and potentially implement this technology as a low-cost "in-home" treatment. Our experiments demonstrated that exposure at 280 nm using an LED with a fluence as low as 0.5 J/cm(2) was inhibitory, i.e., no growth following a 2-week incubation (p < 0.05 one-way ANOVA), while exposure to longer wavelengths was not. A key requirement for the use of phototherapy in the treatment of onychomycosis is that it must be nail transmissible. Our results indicate that the treatment with UVC is not feasible given that there is no overlap between the antifungal activity observed at 280 nm and transmission through the nail plate. However, a potential indirect application of this technology could be the decontamination of reservoirs of infection such as the shoes of infected in iduals, thus preventing reinfection.
Publisher: The Optical Society
Date: 07-09-2016
DOI: 10.1364/OE.24.021463
Publisher: Optica Publishing Group
Date: 08-10-2019
DOI: 10.1364/OL.44.002506
Publisher: IEEE
Date: 07-2017
Publisher: IOP Publishing
Date: 17-05-2023
Abstract: In its 60 years of existence, the field of nonlinear optics has gained momentum especially over the past two decades thanks to major breakthroughs in material science and technology. In this article, we present a new set of data tables listing nonlinear-optical properties for different material categories as reported in the literature since 2000. The papers included in the data tables are representative experimental works on bulk materials, solvents, 0D–1D–2D materials, metamaterials, fiber waveguiding materials, on-chip waveguiding materials, hybrid waveguiding systems, and materials suitable for nonlinear optics at THz frequencies. In addition to the data tables, we also provide best practices for performing and reporting nonlinear-optical experiments. These best practices underpin the selection process that was used for including papers in the tables. While the tables indeed show strong advancements in the field over the past two decades, we encourage the nonlinear-optics community to implement the identified best practices in future works. This will allow a more adequate comparison, interpretation and use of the published parameters, and as such further stimulate the overall progress in nonlinear-optical science and applications.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 02-2002
Publisher: The Optical Society
Date: 04-06-2015
DOI: 10.1364/OE.23.015504
Publisher: Optica Publishing Group
Date: 20-03-2020
DOI: 10.1364/OL.387879
Abstract: Laser guide stars based on the mesospheric sodium layer are becoming increasingly important for applications that require correction of atmospheric scintillation effects. Despite several laser approaches being investigated to date, there remains great interest in developing lasers with the necessary power and spectral characteristics needed for brighter single or multiple guide stars. Here we propose and demonstrate a novel, to the best of our knowledge, approach based on a diamond Raman laser with intracavity Type I second-harmonic generation pumped using a 1018.4 nm fiber laser. A first demonstration with output power of 22 W at 589 nm was obtained at 18.6% efficiency from the laser diode. The laser operates in a single longitudinal mode (SLM) with a measured linewidth of less than 8.5 MHz. The SLM operation is a result of the strong mode competition arising from the combination of a spatial-hole-burning-free gain mechanism in the diamond and the role of sum frequency mixing in the harmonic crystal. Continuous tuning through the Na D line resonance is achieved by cavity length control, and broader tuning is obtained via the tuning of the pump wavelength. We show that the concept is well suited to achieve much higher power and for temporal formats of interest for advanced concepts such as time-gating and Larmor frequency enhancement.
Publisher: IEEE
Date: 12-2014
Publisher: Elsevier BV
Date: 08-2022
Publisher: The Optical Society
Date: 12-05-2014
DOI: 10.1364/OL.39.002975
Publisher: OSA
Date: 2019
Publisher: Optica Publishing Group
Date: 15-06-2005
DOI: 10.1364/OL.30.001500
Abstract: We report an all-solid-state intracavity Raman laser with intracavity nonlinear sum-frequency generation providing visible output wavelengths selected from second harmonics and sum frequencies of the fundamental and Stokes fields. The laser comprises a diode end-pumped Nd:YAG laser, an acousto-optic Q switch, a KGd(WO4)2 Raman crystal, and a lithium borate nonlinear converter in a resonator designed to accommodate dynamic thermal lensing. For 20 W of pump power, output powers up to 1.8 W are demonstrated at wavelengths of 532, 555, 579, and 606 nm, selectable by angle and temperature tuning of the nonlinear medium.
Publisher: OSA
Date: 2006
Publisher: IOP Publishing
Date: 06-2021
Abstract: We propose a high-sensitivity magnetometry scheme based on a diamond Raman laser with visible pump absorption by an ensemble of coherently microwave driven negatively charged nitrogen-vacancy centres (NV − ) in the same diamond crystal. The NV − centres’ absorption and emission are spin-dependent. We show how the varying absorption of the NV − centres changes the Raman laser output. A shift in the diamond Raman laser threshold and output occurs with the external magnetic field and microwave driving. We develop a theoretical framework with steady-state solutions to describe the effects of coherently driven NV − centres including the charge state switching between NV − and its neutral charge state NV 0 in a diamond Raman laser. We discuss that such a laser working at the threshold can be employed for magnetic field sensing. In contrast to previous studies on NV − magnetometry with visible laser absorption, the laser threshold magnetometry method is expected to have low technical noise, due to low background light in the measurement signal. For magnetic-field sensing, we project a shot-noise limited DC sensitivity of a few pT / H z in a well-calibrated cavity with realistic parameters. This sensor employs the broad visible absorption of NV − centres and unlike previous laser threshold magnetometry proposals it does not rely on active NV − centre lasing or an infrared laser medium at the specific wavelength of the NV − centre’s infrared absorption line.
Publisher: AIP Publishing
Date: 14-09-2020
DOI: 10.1063/5.0020405
Abstract: Ultraviolet laser-induced etching is a method of machining and nanostructuring diamond surfaces in which carbon is removed from the surface via a photochemical process involving oxygen. We show here that using a dry source of oxygen at pressures in the range of 0.01–1 Torr leads to a 10-fold increase in the etch rate compared to etching in atmospheric air. The enhanced etch rate is also found to be accompanied by a marked change in the nanopatterned surface morphology. We developed a rate equation model for the etch rate that provides good agreement with measurements for pressures up to approximately 0.1 Torr. For higher pressures, the reduced etch rate and departure from the model are attributed to the contamination of the diamond surface by trace amounts of water vapor, introduced as an impurity from the gas sources. The results provide a method for markedly increasing the etch rate, as well as a better understanding of the role of gas impurities on the etch mechanism and emergent nanopattern formation.
Publisher: Optica Publishing Group
Date: 05-01-2021
DOI: 10.1364/OE.410287
Abstract: Intrinsic randomness in quantum systems is a vital resource for cryptography and other quantum information protocols. To date, randomizing macroscopic polarization states requires randomness from an external source, which is then used to modulate the polarization e.g. for quantum key-distribution protocols. Here, we present a Raman-based device for directly generating laser pulses with quantum-randomized polarizations. We show that crystals of diamond lattice symmetry provide a unique operating point for which the Raman gain is isotropic, so that the spontaneous symmetry breaking initiated by the quantum-random zero-point motion determines the output polarization. Experimentally measured polarizations are demonstrated to be consistent with an independent and identical uniform distribution with an estimated quantum entropy rate of 3.8 bits ulse.
Publisher: The Optical Society
Date: 04-02-2019
DOI: 10.1364/OL.44.000839
Publisher: No publisher found
Date: 2001
Publisher: Optica Publishing Group
Date: 11-02-2010
DOI: 10.1364/OL.35.000556
Publisher: IOP Publishing
Date: 10-2015
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEOPR.2020.C10C_5
Abstract: We report the generation of Raman laser pulses in diamond with quantum-random polarisation, whereby laser pulses exhibit a coherent, well-defined, linear polarisation with an orientation that is random from pulse to pulse. © 2020 The Author(s)
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2011
Publisher: Optica Publishing Group
Date: 05-03-2007
DOI: 10.1364/OL.32.000814
Abstract: We report a KGd(WO(4))(2) Raman laser pumped by a 532 nm laser that uses the intracavity nonlinear second harmonic and sum-frequency mixing of the Stokes and fundamental fields in beta-barium borate to generate selectable output among eight output wavelengths over the range 266-320 nm. Output pulse energies of up to 0.22 mJ at 10 Hz pulse repetition rate and average output powers up to 48 mW at 5 kHz were achieved.
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEOPR.2020.P1_18
Abstract: Low power UV laser radiation has been previously found to etch diamond surfaces via a multiphoton process. Here we show that UV exposure also increases the NV photoluminescence and enhances hydrogen-terminated surface conductivity.
Publisher: Optica Publishing Group
Date: 11-10-2022
DOI: 10.1364/OL.471447
Abstract: Stimulated Brillouin scattering (SBS), with its advantages of low quantum defect and narrow gain bandwidth, has recently enabled an exciting path toward narrow-linewidth and low-noise lasers. Whereas almost all work to date has been in guided-wave configurations, adaptation to unguided Brillouin lasers (BLs) offers a greater capacity for power scaling, cascaded Stokes control, and greater flexibility for expanding wavelength range. Here, we report a diamond Brillouin laser (DBL) employing doubly resonant technology at 1064 nm. Brillouin output power of 22.5 W with a linewidth of 46.9 kHz is achieved. The background noise from the pump lified spontaneous emission (ASE) is suppressed by 35 dB. The work represents a significant step toward realizing Brillouin oscillators that simultaneously have high power (tens-of-watts+) and kHz-linewidths.
Publisher: IEEE
Date: 08-2011
Publisher: IOP Publishing
Date: 07-12-2000
Publisher: Optica Publishing Group
Date: 05-05-2020
DOI: 10.1364/OE.388794
Abstract: We report experimental observations of thermal lens effects in a diamond Raman laser operating up to 1.1 kW output power in a quasi- steady-state regime. Measured changes in the output beam parameters as a function of output power, including beam quality factor and beam ergence after a fixed focusing lens, are compared to modelling enabling us to track the development of a thermal lens up to 16 diopters at maximum output power. Analysis shows that good agreement between model and experiment is obtained by considering the power deposition profile and the spatial overlap with the laser mode. The results clarify previous work that raised questions about thermal lens effects in the diamond gain medium and provides increased confidence in thermal models for determining the power limits for the current design.
Publisher: IEEE
Date: 08-2015
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEOPR.2020.C6A_3
Abstract: We demonstrate a Raman laser continuously tunable in the visible range, capable of performing element-selective photo-ionization. The Stokes outputs exhibited a linewidth of 11.0 ± 1.0 GHz with a conversion efficiency of more than 60%. © 2020 The Authors
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 1997
DOI: 10.1109/3.631272
Publisher: Optica Publishing Group
Date: 14-06-2007
DOI: 10.1364/OE.15.008170
Abstract: Recent experiments have shown that the simple addition of a length of Raman-shifting fibre in the cavity of a cw-pumped fibre laser can cause the laser to generate a stable train of pulses [Zhao and Jackson, Opt. Lett., 31 751 (2006)]. We show using a numerical model that this behavior is a new type of mode locking, driven by backward stimulated Raman scattering. This mode locking mechanism could also be applied to crystalline Raman laser systems to create a novel picosecond oscillator.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 06-2003
Publisher: No publisher found
Date: 2002
Publisher: IEEE
Date: 2005
Publisher: Optica Publishing Group
Date: 10-03-2020
DOI: 10.1364/OE.384630
Abstract: We demonstrate a continuously tunable, multi-Stokes Raman laser operating in the visible range (420 - 600 nm). Full spectral coverage was achieved by efficiently cascading the Raman shifted output of a tunable, frequency-doubled Ti:Sapphire laser. Using an optimized hemi-spherical external Raman cavity composed only of a diamond crystal and a single reflecting mirror, producing high power output at high conversion efficiency ( % from pump to Stokes) for a broad range of wavelengths across the visible. Enhancement of the cascading was achieved by controlling the polarization state of the pump and Stokes orders. The Stokes outputs exhibited a linewidth of 11 ± 1 GHz for each order, resembling the pump laser linewidth, enabling its use for the intended spectroscopic applications. Furthermore, the Raman laser performance was demonstrated by applying it for the resonance excitation of atomic transitions in calcium.
Publisher: The Optical Society
Date: 12-07-2011
DOI: 10.1364/OME.1.000576
Publisher: Springer Science and Business Media LLC
Date: 11-2003
Publisher: SPIE
Date: 25-01-2001
DOI: 10.1117/12.414053
Publisher: IEEE
Date: 2003
Publisher: IEEE
Date: 08-2015
Publisher: Springer Science and Business Media LLC
Date: 04-03-2014
DOI: 10.1038/NCOMMS4341
Abstract: Optical techniques have advanced considerably in recent years to enable processing of surfaces with a resolution less than the wavelength of light. Despite the highly selective nature of light-matter interactions, however, efforts to increase resolution to the scale of single atoms are h ered by rapid and efficient dissipation of the absorbed energy to the surrounding matrix. Here we show that two-photon surface excitation using ultraviolet light provides a method for selectively removing carbon from diamond surfaces. Polished surfaces etched by this method develop ultra-deep subwavelength structures with morphologies dependent on the polarization of the incident laser with respect to the crystal axes. As well as revealing a practical and versatile method for nano-patterning of diamond surfaces, we show that the results comprise mesoscopic evidence for bond scission via a highly localized optical interaction that may lead to the development of new optical approaches for ultra-nanoscale (<10 nm) surface structuring.
Publisher: SPIE
Date: 02-04-2004
DOI: 10.1117/12.552735
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2000
DOI: 10.1109/3.831019
Publisher: MDPI AG
Date: 13-08-2022
DOI: 10.3390/MI13081311
Abstract: Delayed self-heterodyne/homodyne measurements based on an unbalanced interferometer are the most used methods for measuring the linewidth of narrow-linewidth lasers. They typically require the service of a delay of six times (or greater) than the laser coherence time to guarantee the Lorentzian characteristics of the beat notes. Otherwise, the beat notes are displayed as a coherent envelope. The linewidth cannot be directly determined from the coherence envelope. However, measuring narrow linewidths using traditional methods introduces significant errors due to the 1/f frequency noise. Here, a short fiber-based linewidth measurement scheme was proposed, and the influence of the noise floor on the measurement of the laser linewidth using this scheme was studied theoretically and experimentally. The results showed that this solution and calibration process is capable of significantly improving the measurement accuracy of narrow linewidth.
Publisher: Optica Publishing Group
Date: 13-08-2004
DOI: 10.1364/OL.29.001882
Abstract: A microstructured polymer optical fiber doped with Rhodamine 6G dye was fabricated and demonstrated as an optical lifier and a fiber laser. As an lifier, the fiber achieved a gain in excess of 30 dB. As a pulsed fiber laser, the fiber exhibited a threshold of 20 microJ, a slope efficiency of 18%, and a lifetime as high as 130,000 shots at 10 Hz. The maximum output energy was 16 microJ. The advantages that such fibers offer lie in the simplicity and flexibility of their fabrication and in their potential for use as compact, tunable solid-state sources.
Publisher: IEEE
Date: 2000
Publisher: AIP Publishing
Date: 27-02-2023
DOI: 10.1063/5.0137542
Abstract: We report on the design and operation of a laser, which outputs wavelengths in the 1.2 and 1.5 μm ranges by leveraging two non-linear processes of stimulated Raman scattering and stimulated Brillouin scattering in diamond. By precisely controlling characteristics of the laser resonator formed around the diamond crystal, we are able to selectively control the onset of each non-linear process so as to tailor laser output characteristics both in way of wavelength and output power. This work demonstrates the high degree of flexibility and power-handling capacity of diamond for wavelength conversion of common laser wavelengths (such as 1064 nm as used in this work) and the generation of a span of discrete wavelengths (with up to eight cascaded orders being demonstrated in this work).
Publisher: The Optical Society
Date: 19-05-2011
DOI: 10.1364/OE.19.010857
Publisher: OSA
Date: 2014
Publisher: SPIE
Date: 23-03-2005
DOI: 10.1117/12.611075
Publisher: IEEE
Date: 2005
Publisher: OSA
Date: 2005
Publisher: Optica Publishing Group
Date: 27-08-2021
DOI: 10.1364/OE.435023
Abstract: We report a diamond Raman laser that is continuously-tunable across the range from 590 nm to 625 nm producing continuous wave output with up to 8 W. The system is based on an all-fiber and tunable (1020–1072 nm) Yb-doped pump laser with a spectral linewidth of 25 GHz that is Raman-shifted and frequency doubled in a cavity containing diamond and a lithium triborate second harmonic crystal. Despite the broad pump spectrum, single frequency output is obtained across the tuning range 590–615 nm. The results reveal a practical approach to obtain tunable high-power single-frequency laser in a wavelength region not well served by other laser technologies.
Publisher: The Optical Society
Date: 17-03-2017
DOI: 10.1364/OL.42.001229
Publisher: IOP Publishing
Date: 07-08-1998
Publisher: IOP Publishing
Date: 06-06-2014
Publisher: OSA
Date: 2018
Publisher: OSA
Date: 2018
Publisher: Optica Publishing Group
Date: 22-12-2020
DOI: 10.1364/OE.413098
Abstract: We describe a theoretical approach based on Müller and tensor calculus for predicting the polarization state and gain of cascaded Stokes orders produced under coherent Raman scattering regime conditions. The formulation follows a Markovian-style implementation for F 2 g -type modes in Raman cubic crystals. The theoretical model is supported by experimental results that corroborate that the polarization and power of the cascaded Stokes orders can be effectively predicted using sequential calculus. We extend these results to a variety of crystal propagation directions, with the aim of facilitating the design of advanced solid-state Raman lasers.
Publisher: Elsevier BV
Date: 2004
Publisher: SPIE
Date: 25-01-2001
DOI: 10.1117/12.414046
Publisher: The Optical Society
Date: 21-11-2016
DOI: 10.1364/OE.24.027812
Publisher: Optica Publishing Group
Date: 2021
Abstract: We report on large power spectral density enhancement (~40 × ) of high power nanosecond lasers via coherent Raman conversion in an Fabry-Pérot diamond resonator. The device produced directly a phase locked, near Fourier-limited Stokes output without the need of cavity length stabilization.
Publisher: Optica Publishing Group
Date: 10-09-2009
DOI: 10.1364/OL.34.002811
Publisher: OSA
Date: 2018
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2005
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/AM13040
Abstract: Scats of long-nosed bandicoots (Perameles nasuta) from north-eastern New South Wales were examined for seasonal occurrence of fungi. Fungus was detected in bandicoot diets in all seasons, but s les from autumn and winter were more likely to contain fungi, and more taxa were consumed in these seasons, compared with spring and summer. In idual scat s les also contained more spore types in autumn and winter than in spring and summer. My results support other work in temperate south-eastern Australia that indicate an autumn and winter peak in fungal availability, and a stronger focus on fungal consumption by mammals at this time of year.
Publisher: IEEE
Date: 08-2011
Publisher: SPIE
Date: 30-12-2019
DOI: 10.1117/12.2539583
Publisher: Optica Publishing Group
Date: 07-1997
DOI: 10.1364/AO.36.004526
Abstract: The hook method is a well-established technique for measuring the spatial distribution of species' densities in the gas phase, particularly in optically thick plasmas. However, in the presence of large density gradients (such as those occurring in a metal vapor laser plasma), the hook interferogram suffers severe distortion and the standard hook equation is invalid. By the use of a computer simulation of fringe formation, it is shown that this effect arises as a result of the strong wavelength-dependent lensing of probe rays in the test medium. On the basis of this lensing mechanism, a criterion has been derived for the maximum permissible density gradient, above which the standard hook analysis cannot be accurately applied. Finally, a new technique is presented that permits density data to be recovered from interferograms that are too distorted to analyze by the use of standard techniques. This technique is based on extracting density gradient values from distortion-free features of the fringe pattern. The new technique also permits density data to be obtained with an increased spatial resolution over that of the standard hook analysis.
Publisher: IEEE
Date: 2005
Publisher: American Geophysical Union (AGU)
Date: 03-2011
DOI: 10.1029/2011GL046827
Publisher: Optica Publishing Group
Date: 24-07-2018
DOI: 10.1364/OE.26.019797
Publisher: Springer Science and Business Media LLC
Date: 07-02-2017
DOI: 10.1038/SREP41702
Abstract: Nonlinear conversion of unpolarized beams to lower frequencies is generally inefficient in c (2) materials, as it is challenging to achieve phase-matching for input ordinary and extraordinary beams simultaneously in the normal dispersion regime. Here, we show that cubic Raman crystals having doubly and triply degenerate ( E and F type) modes provide a method for efficient nonlinear frequency downconversion of an unpolarized beam and yield a linearly polarized output state. Using Mueller calculus, optimal crystal directions for such polarization conversion are determined. Using diamond, an ex le of an F -class Raman crystal, we have verified that such conversion is possible with near quantum-defect-limited slope efficiency and a linear polarization contrast of more than 23.9 dB.
Publisher: Springer Science and Business Media LLC
Date: 24-08-2005
Start Date: 08-2016
End Date: 09-2019
Amount: $358,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 03-2010
End Date: 03-2014
Amount: $788,800.00
Funder: Australian Research Council
View Funded ActivityStart Date: 08-2022
End Date: 08-2025
Amount: $663,541.00
Funder: Australian Research Council
View Funded ActivityStart Date: 05-2015
End Date: 12-2018
Amount: $414,400.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2013
End Date: 12-2015
Amount: $225,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2012
End Date: 12-2015
Amount: $270,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2020
End Date: 12-2020
Amount: $400,000.00
Funder: Australian Research Council
View Funded Activity