ORCID Profile
0000-0001-9094-714X
Current Organisation
Shenzhen University
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Publisher: OSA
Date: 2017
Publisher: IOP Publishing
Date: 09-04-2021
Abstract: C-coated SiC nanocomposites (SiC@C NCs) were one-step synthesized under a mixture atmosphere of Ar and CH 4 using a DC arc-discharge plasma method. The microstructure of the composites could be controlled by varying the volume ratio of Ar and CH 4 . A strong response to the terahertz (THz) field was observed due to the existence of a graphite shell. The dielectric properties of SiC@C NCs can be enhanced by altering the thickness of the graphite shell. The thicker graphite shell results in a stronger absorption of THz waves and an enhanced real part of conductivity. Fitting the measured conductivity data using the Drude–Smith model reveals that the carrier transport in the SiC@C NCs and its counterpart, the SiC nanoparticles, is dominated by backscattering. The SiC@C NCs with enhanced conductivity are believed to be fundamental materials for various functionalized optoelectronic devices.
Publisher: China Science Publishing & Media Ltd.
Date: 2019
Publisher: Elsevier BV
Date: 08-2021
Publisher: China Science Publishing & Media Ltd.
Date: 2019
Publisher: Frontiers Media SA
Date: 27-08-2019
Publisher: Optica Publishing Group
Date: 15-08-2022
DOI: 10.1364/OE.463660
Abstract: We developed a GaAs Schottky diode with integrated periodic subwavelength metal microslits with total internal reflection (TIR) geometry to achieve deep broadband THz modulation at high frequency with low insertion loss. The non-resonant electric field enhancement effect in the subwavelength microslits intensifies the evanescent wave in TIR, which increases broadband absorbance of THz light signals by free carriers in the GaAs Schottky diode. Devices with various microslit spatial periods and gap widths were fabricated and measured. Among the devices, that with a microslit period of 10 µm and gap width of 2 µm produced ∼70% modulation depth at frequencies of 0.2 to 1.2 THz, while in the range of 0.25 to 0.4 THz, ∼90% modulation depth was achieved. By encapsulating the device in high refractive index material, ∼100% modulation depth was achieved in the range of 0.4 to 0.6 THz, the 3 dB bandwidth operational frequency was ∼160 kHz, and the insertion loss introduced by the device was less than 8 dB, which is much lower than existing metasurface-based THz modulators. In general, our first-generation device has improved modulation depth, operational bandwidth, insertion loss, and operational frequency. Optimization of the metal microslits, TIR geometry, and doped layer could further improve the performance of our design.
Publisher: IEEE
Date: 08-2015
Publisher: IEEE
Date: 17-12-2022
Publisher: IEEE
Date: 28-08-2022
Publisher: IEEE
Date: 29-08-2021
Publisher: Optica Publishing Group
Date: 22-06-2022
DOI: 10.1364/BOE.461414
Abstract: We presented a strategy for enhancing the sensitivity of terahertz glucose sensing with a hydrogel platform pre-embedded with Au nanoparticles. Physiological-level glucose solutions ranging from 0 to 0.8 mg/mL were measured and the extracted absorption coefficients can be clearly distinguished compared to traditional terahertz time domain spectroscopy performed directly on aqueous solutions. Further, Isotherm models were applied to successfully describe the relationship between the absorption coefficient and the glucose concentration (R 2 = 0.9977). Finally, the origin of the sensitivity enhancement was investigated and verified to be the pH change induced by the catalysis of Au nanoparticles to glucose oxidation.
Publisher: Elsevier BV
Date: 02-2022
Publisher: IEEE
Date: 17-12-2022
Publisher: The Optical Society
Date: 26-02-2018
DOI: 10.1364/BOE.9.001334
Publisher: Wiley
Date: 02-11-2016
Abstract: We use terahertz imaging to measure four human skin scars in vivo. Clear contrast between the refractive index of the scar and surrounding tissue was observed for all of the scars, despite some being difficult to see with the naked eye. Additionally, we monitored the healing process of a hypertrophic scar. We found that the contrast in the absorption coefficient became less prominent after a few months post-injury, but that the contrast in the refractive index was still significant even months post-injury. Our results demonstrate the capability of terahertz imaging to quantitatively measure subtle changes in skin properties and this may be useful for improving scar treatment and management.
Publisher: Elsevier BV
Date: 09-2022
Publisher: American Chemical Society (ACS)
Date: 18-02-2020
Publisher: Elsevier BV
Date: 11-2022
Publisher: IOP Publishing
Date: 28-08-2014
Publisher: IOP Publishing
Date: 21-09-2021
Publisher: CRC Press
Date: 13-06-2014
DOI: 10.1201/B17060-20
Publisher: IEEE
Date: 09-2016
Publisher: IEEE
Date: 08-2015
Publisher: American Chemical Society (ACS)
Date: 04-09-2019
Publisher: SPIE
Date: 09-10-2019
DOI: 10.1117/12.2534282
Publisher: IEEE
Date: 09-2013
Publisher: Optica Publishing Group
Date: 12-02-2021
DOI: 10.1364/OE.413622
Abstract: Potential applications of terahertz (THz) radiation are constantly being investigated for high-speed communication due to its large bandwidth. For ex le, frequency hopping communication technology would benefit from the large bandwidth. To attach the information to the carrier wave, THz modulators with deep and stable modulation at different frequencies are crucial, yet are still lacking. Here a THz modulator, designed by integrating a non-resonant field enhancement effect of periodic metal microslits to assist a Fabry-Perot resonance structure (MS-FP) is proposed and demonstrated. New equations are developed to describe the superior performance of the novel design. The % modulation depth is achieved by a SiO 2 /Si gated graphene device at 14 Fabry-Perot resonant frequencies across 1.4 THz bandwidth, outperforming the recently reported 75% modulation depth THz modulator with a similar Fabry-Perot structure.
Publisher: Optica Publishing Group
Date: 19-10-2022
DOI: 10.1364/OL.472923
Abstract: Highly sensitive terahertz (THz) sensing with metasurfaces has attracted considerable attention recently. However, ultrahigh sensing sensitivity remains a huge challenge for practical applications. To improve the sensitivity of these devices, herein we have proposed an out-of-plane metasurface-assisted THz sensor consisting of periodically arranged bar-like meta-atoms. Benefiting from elaborate out-of-plane structures, the proposed THz sensor with high sensing sensitivity of 325 GHz/RIU can be easily fabricated via a simple three-step fabrication process, and the maximum sensing sensitivity can be ascribed to toroidal dipole resonance-enhanced THz-matter interactions. The sensing ability of the fabricated sensor is experimentally characterized by the detection of three types of analytes. It is believed that the proposed THz sensor with ultrahigh sensing sensitivity and its fabrication method might provide great potential in emerging THz sensing applications.
Publisher: IEEE
Date: 09-2018
Publisher: IEEE
Date: 09-2012
Publisher: IOP Publishing
Date: 13-03-2015
DOI: 10.1088/0031-9155/60/7/2703
Abstract: S le dehydration has traditionally been a challenging problem in ex vivo terahertz biomedical experiments as water content changes significantly affect the terahertz properties and can diminish important contrast features. In this paper, we propose a novel method to prevent s le dehydration using gelatin embedding. By looking at terahertz image data and calculating the optical properties of the gelatin-embedded s le, we find that our method successfully preserves the s le for at least 35 h, both for imaging and spectroscopy. Our novel preservation method demonstrates for the first time the capability to simultaneously maintain s le structural integrity and prevent dehydration at room temperature. This is particularly relevant for terahertz studies of freshly excised tissues but could be beneficial for other imaging and spectroscopy techniques.
Publisher: Elsevier BV
Date: 06-2019
Publisher: Springer Science and Business Media LLC
Date: 28-08-2017
DOI: 10.1038/MICRONANO.2017.33
Abstract: The realization of high-performance tunable absorbers for terahertz frequencies is crucial for advancing applications such as single-pixel imaging and spectroscopy. Based on the strong position sensitivity of metamaterials’ electromagnetic response, we combine meta-atoms that support strongly localized modes with suspended flat membranes that can be driven electrostatically. This design maximizes the tunability range for small mechanical displacements of the membranes. We employ a micro-electro-mechanical system technology and successfully fabricate the devices. Our prototype devices are among the best-performing tunable THz absorbers demonstrated to date, with an ultrathin device thickness (~1/50 of the working wavelength), absorption varying between 60% and 80% in the initial state when the membranes remain suspended, and fast switching speed (~27 μs). The absorption is tuned by an applied voltage, with the most marked results achieved when the structure reaches the snap-down state. In this case, the resonance shifts by % of the linewidth (14% of the initial resonance frequency), and the absolute absorption modulation measured at the initial resonance can reach 65%. The demonstrated approach can be further optimized and extended to benefit numerous applications in THz technology.
Publisher: IEEE
Date: 29-08-2021
Publisher: The Optical Society
Date: 31-05-2016
DOI: 10.1364/PRJ.4.000A29
Publisher: American Chemical Society (ACS)
Date: 15-06-2020
Publisher: Springer Science and Business Media LLC
Date: 26-02-2018
Publisher: Elsevier BV
Date: 08-2020
Publisher: IEEE
Date: 09-2016
Publisher: IEEE
Date: 08-2017
Publisher: AIP Publishing
Date: 11-2021
DOI: 10.1063/5.0064643
Abstract: We demonstrate an ultrabroadband electrically controllable terahertz modulator based on a Schottky diode structure formed with periodic metal microslits on an n-doped GaAs substrate. The mechanism of our design is different from that of the traditional Schottky diode-based THz electrical modulator, which uses free charge carriers in a substrate to control the resonant behavior of metamaterials. In our device, the modulation is based on free-carrier absorption on the THz wave and therefore broadband. The charge carrier concentration between the metal microslits is actively modified by applying a reverse bias voltage to generate a direct modulation of THz waves. The modulation performance is enhanced by the THz non-resonant electric field enhancement effect from the metal microslits. The experimental results indicate that the modulation depth is positively correlated with the electric field enhancement ratio at the depletion region in the gap and the number of microslits in the THz light spot-covered area. An averaged modulation depth of ∼40% in the measurable frequency range from 0.4 to 1.4 THz was achieved by the device with a metal microslits gap width of 2 µm and a period of 20 µm. A maximum modulation depth of ∼75% was achieved by stacking two devices back-to-back with a 3-dB down bandwidth modulation speed of ∼100 kHz. Further improvements of the device can be achieved by optimizing the parameters such as the free-carrier density in the doping layer, the active area size, and the specifications of the metal microslits.
Publisher: AME Publishing Company
Date: 06-2017
Publisher: Wiley
Date: 28-05-2023
Abstract: Waveguide tapers are seemingly indispensable elements in silicon photonics that usually operate adiabatically to maximize the coupling efficiency between waveguides with different cross‐sections, which, however, necessitate large footprints. To date, great efforts have been made to minimize the tapers’ footprints while maintaining their efficiency. Contrary to conventional wisdom, here, a concept of taper‐free waveguides is proposed in which waveguides with different cross‐sections couple with each other efficiently without using tapers, which are enabled by the recently discovered photonic topological phases. This concept is experimentally demonstrated on an all‐silicon on‐chip terahertz (THz) wave platform. It is further shown that the topologically enabled taper‐free waveguides are robust against sharp corners and large‐area potential barriers. This work provides a promising taper‐free solution for future compact optical/THz photonic integrated circuits.
Publisher: IEEE
Date: 09-2016
Publisher: SPIE
Date: 09-11-2018
DOI: 10.1117/12.2502287
Publisher: IEEE
Date: 29-08-2021
Publisher: Optica Publishing Group
Date: 28-03-2022
DOI: 10.1364/OE.452416
Abstract: Quantitative detection of neurotransmitters in aqueous environment is crucial for the early diagnosis of many neurological disorders. Terahertz waves, as a non-contact and non-labeling tool, have demonstrated large potentials in quantitative biosensing. Although the detection of trace-amount analyte has been achieved with terahertz metamaterials in the recent decades, most studies have been focused on dried s les. Here, a hexagonal asymmetric metamaterial sensor was designed and fabricated for aqueous solution sensing with terahertz waves in the reflection geometry. An absorption enhancement of 43 was determined from the simulation. Dilute adrenaline solutions ranging from 30 µM to 0.6 mM were measured on our sensor using a commercial terahertz time-domain spectroscopy system, and the effective absorption was found to be linearly correlated with the concentration (R 2 = 0.81). Furthermore, we found that as the concentration becomes higher ( .6 mM), a non-linear relationship starts to take place, which confirmed the previous theory on the extended solvation shell that can be probed on the picosecond scale. Our sensor, without the need of high-power and stable terahertz sources, has enabled the detection of subtle absorption changes induced by the solvation dynamics.
Publisher: The Optical Society
Date: 2009
DOI: 10.1364/BOE.9.002917
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CC00141G
Abstract: Chain-length dependent intermolecular interactions of saturated fatty acids are directly probed with THz-TDS and confirmed by ab initio calculations.
Publisher: American Chemical Society (ACS)
Date: 08-01-2019
DOI: 10.26434/CHEMRXIV.7553054.V1
Abstract: We measured crystalline (C-form) saturated fatty acids with even carbon numbers ranging from 12 to 20 using temperature dependent terahertz time-domain spectroscopy (THz-TDS). Absorption features between 0.5 to 2.75 THz were identified at temperatures from 96 K to 293 K, and a systematic red-shift was obvserved with the increasing carbon chain length. The origins of these absorption bands were uncovered using state-of-the-art ab initio density functional theory (DFT) calculations. Similar vibrational motions in the absorption bands of the different materials highlight the unique role that THz-TDS has for probing weak non-covalent interactions in these materials. Our results showcase the utility of the terahertz region, which is beyond the scope of related vibrational techniques, providing direct evidence of the effect of chain length on the intermolecular interactions of these molecules.
Publisher: Wiley
Date: 03-10-2022
Abstract: Chiral metasurfaces with pronounced reflective chiroptical responses have drawn extensive attention as they can offer great opportunities for various chirality‐related applications. However, their fascinating potential are restrained by limited chiroptical responses, relatively complex design principle, and fabrication strategy. Herein, a concise and general design principle to develop out‐of‐plane reflective chiral metasurfaces, empowered with the maximum theoretical circular dichroism (CD), is theoretically proposed and experimentally demonstrated. The designed out‐of‐plane chiral metasurfaces operating in the terahertz (THz) region are flexibly fabricated via a simple, scalable, low‐cost and lithography‐free fabrication strategy by integrating a three‐dimensional (3D) printing technique. Finally, the methodological stabilities and the strong chiroptical responses of proposed chiral metasurfaces are validated experimentally. From the general design principle, simple fabrication strategy as well as maximum chiroptical responses of proposed reflective chiral metasurfaces, it can be envisaged that these findings may overcome the difficulties in design, optimization, and fabrication for reflective chiral metasurfaces and provide promising potentials for various chirality‐related applications in emerging THz technologies, such as chiral sensing, imaging, spectroscopy and polarimetry.
Publisher: Optica Publishing Group
Date: 29-03-2022
DOI: 10.1364/PRJ.451344
Abstract: Terahertz (THz) topological photonic structures are promising for last-centimeter communication in intra/interchip communication systems because they support bit-error-free THz signal transmission with topological robustness. Active and dynamically tunable THz topological photonic components have not yet been experimentally realized. Here, we experimentally demonstrate a THz topological switch (270–290 GHz) based on a valley Hall photonic crystal structured high-resistivity silicon substrate, in which the THz waves can be dynamically turned on/off by an external 447 nm continuous-wave laser. Our device exhibited an on/off ratio of 19 dB under a pumping light intensity of 240 mW / mm 2 . The 3 dB switching bandwidth was ∼ 60 kHz .
Publisher: IEEE
Date: 08-2014
Publisher: Elsevier BV
Date: 10-2022
Publisher: IEEE
Date: 02-07-2023
Publisher: IEEE
Date: 28-08-2022
No related grants have been discovered for Shuting Fan.