ORCID Profile
0000-0003-3804-4722
Current Organisations
Chiba University
,
Istituto nazionale di astrofisica
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Photonics, Optoelectronics and Optical Communications | Nanophotonics | Nanotechnology | Nanofabrication, Growth and Self Assembly
Expanding Knowledge in the Physical Sciences | Communication Networks and Services not elsewhere classified | Expanding Knowledge in Technology |
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-1998
DOI: 10.1109/68.730483
Publisher: The Optical Society
Date: 16-04-2012
DOI: 10.1364/OE.20.009810
Publisher: EDP Sciences
Date: 04-2018
DOI: 10.1051/0004-6361/201731169
Abstract: Context. The large jet kinetic power and non-thermal processes occurring in the microquasar SS 433 make this source a good candidate for a very high-energy (VHE) gamma-ray emitter. Gamma-ray fluxes above the sensitivity limits of current Cherenkov telescopes have been predicted for both the central X-ray binary system and the interaction regions of SS 433 jets with the surrounding W50 nebula. Non-thermal emission at lower energies has been previously reported, indicating that efficient particle acceleration is taking place in the system. Aim. We explore the capability of SS 433 to emit VHE gamma rays during periods in which the expected flux attenuation due to periodic eclipses ( P orb ~ 13.1 days) and precession of the circumstellar disk ( P pre ~ 162 days) periodically covering the central binary system is expected to be at its minimum. The eastern and western SS 433/W50 interaction regions are also examined using the whole data set available. We aim to constrain some theoretical models previously developed for this system with our observations. Methods. We made use of dedicated observations from the Major Atmospheric Gamma Imaging Cherenkov telescopes (MAGIC) and High Energy Spectroscopic System (H.E.S.S.) of SS 433 taken from 2006 to 2011. These observation were combined for the first time and accounted for a total effective observation time of 16.5 h, which were scheduled considering the expected phases of minimum absorption of the putative VHE emission. Gamma-ray attenuation does not affect the jet/medium interaction regions. In this case, the analysis of a larger data set amounting to ~40–80 h, depending on the region, was employed. Results. No evidence of VHE gamma-ray emission either from the central binary system or from the eastern/western interaction regions was found. Upper limits were computed for the combined data set. Differential fluxes from the central system are found to be ≲ 10 −12 –10 −13 TeV −1 cm −2 s −1 in an energy interval ranging from ~few × 100 GeV to ~few TeV. Integral flux limits down to ~ 10 −12 –10 −13 ph cm −2 s −1 and ~ 10 −13 –10 −14 ph cm −2 s −1 are obtainedat 300 and 800 GeV, respectively. Our results are used to place constraints on the particle acceleration fraction at the inner jetregions and on the physics of the jet/medium interactions. Conclusions. Our findings suggest that the fraction of the jet kinetic power that is transferred to relativistic protons must be relatively small in SS 433, q p ≤ 2.5 × 10 −5 , to explain the lack of TeV and neutrino emission from the central system. At the SS 433/W50 interface, the presence of magnetic fields ≳10 μ G is derived assuming a synchrotron origin for the observed X-ray emission. This also implies the presence of high-energy electrons with E e − up to 50 TeV, preventing an efficient production of gamma-ray fluxes in these interaction regions.
Publisher: Elsevier BV
Date: 12-2004
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2023
Publisher: Springer Science and Business Media LLC
Date: 23-11-2011
Publisher: Optica Publishing Group
Date: 2005
Abstract: Thermal load in Nd3+ doped vanadate crystals with and without laser action at 1.34 mum is investigated. Excited state absorption contributes significantly to a fractional thermal loading as well as quantum defect.
Publisher: IOP Publishing
Date: 20-11-2017
Publisher: Springer Science and Business Media LLC
Date: 02-03-2012
Publisher: American Astronomical Society
Date: 09-05-2017
Publisher: Springer Science and Business Media LLC
Date: 08-08-2009
Publisher: Springer Science and Business Media LLC
Date: 08-02-2013
Publisher: Springer Science and Business Media LLC
Date: 20-11-2019
DOI: 10.1038/S41586-019-1754-6
Abstract: Long-duration γ-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectronvolt-to-megaelectronvolt band, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission
Publisher: American Astronomical Society
Date: 20-09-1999
DOI: 10.1086/307740
Publisher: WORLD SCIENTIFIC
Date: 26-02-2018
DOI: 10.1142/10986
Publisher: Optica Publishing Group
Date: 12-08-2021
DOI: 10.1364/OE.436110
Abstract: We demonstrate an end-pumped Laguerre-Gaussian (LG) mode-selectable Nd:YVO 4 laser utilizing enhanced intracavity spherical aberration. The cavity was designed to exploit strong spherical aberration generated by an expanded beam, incident on a short-focal-length lens, which enabled oscillation of cavity modes of different order. This compact-cavity laser could operate efficiently with high-order LG mode, with the order of this mode being selectively changed by simply adjusting the distance between the short-focal-length lens and the output coupler. Scalar LG modes from LG 0,±10 to up to LG 0,±33 were observed in the experiment. The output power of the LG 0, ±33 mode was 1.87 W under an absorbed pump power of 6.6 W.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 28-11-2014
Abstract: Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet.
Publisher: The Optical Society
Date: 28-02-2014
DOI: 10.1364/OE.22.005400
Publisher: Springer Science and Business Media LLC
Date: 03-2016
Publisher: Springer Science and Business Media LLC
Date: 03-2003
Publisher: The Optical Society
Date: 13-05-2013
DOI: 10.1364/OE.21.012401
Publisher: AIP Publishing
Date: 15-03-1998
DOI: 10.1063/1.367077
Abstract: Thermal lensing in compact neodymium yttrium aluminium garnet slabs and rods end pumped with a beam brought to a line focus has been measured using holographic lateral shearing interferometry. This powerful technique enabled us to directly measure thermal lenses with focal lengths in the range 0.02–12 m with an accuracy of 12% and good spatial resolution. It was found that the line focused pump beam resulted in severe astigmatic thermal lensing. The measured thermal lens strongly deviated from the ideal parabolic profile along both axes, introducing an important additional consideration for laser-diode end-pumped laser resonator design. The degree of longitudinal heat flow was found to strongly influence thermal lens power. It is anticipated that results obtained from the measurement technique presented here will enable optimal design of high-power end-pumped solid-state laser cavities.
Publisher: Optica Publishing Group
Date: 20-03-2001
DOI: 10.1364/AO.40.001372
Abstract: We present a new all-optical technique to measure the thermal conductivity of laser crystals. This technique can be used for crystals that are too small for direct measurement of thermal conductivity. We used this technique to measure the thermal conductivities of Nd:LYAB, with the result of 44 +/- 6% compared with that of Nd:YAG thermal conductivity.
Publisher: Elsevier BV
Date: 03-2004
Publisher: Springer Science and Business Media LLC
Date: 18-08-2007
Publisher: Optica Publishing Group
Date: 30-07-2020
DOI: 10.1364/OE.400007
Abstract: We demonstrate a continuous-wave self-Raman Nd:GdVO 4 Laguerre-Gaussian (LG) mode laser based on different Raman shifts of 382 cm −1 and 882 cm −1 by shaping the pumping beam with the use of an axicon lens and a focusing lens. Selective generation of LG mode beams at 1108 nm or 1173 nm, or simultaneously 1108 nm and 1173 nm, was achieved by carefully adjusting the alignment of the laser cavity. The maximum Raman LG mode output powers at the wavelengths of 1108 nm (the first-Stokes emission of the 382 cm −1 Raman shift) and 1173 nm (the first-Stokes emission of the 882 cm −1 Raman shift) were measured to be 49.8 mW and 133.4 mW at the absorbed pump power of 5.69 W, respectively. The generated LG modes, formed via the incoherent superposition of two LG mode beams with positive and negative topological charges, carry zero orbital angular momentum. Such LG mode laser sources have the potential to fill in the wavelength gap of lasers in the visible and infrared regions.
Start Date: 11-2022
End Date: 11-2025
Amount: $350,000.00
Funder: Australian Research Council
View Funded Activity