Article
Materials Science, Multidisciplinary
Jin-Hong Seok, Uros Puc, Seung-Jun Kim, Woojin Yoon, Hoseop Yun, In Cheol Yu, Fabian Rotermund, Dongwook Kim, Mojca Jazbinsek, O-Pil Kwon
Summary: In this study, high-density organic electro-optic crystals were developed to efficiently generate THz waves in a broad range up to 15 THz, providing a more accessible option for ultra-broadband THz applications. The newly developed OHP-TFS crystals show significantly improved performance compared to traditional inorganic-based THz generators, offering potential for high-accuracy optical characterization in a wide THz range.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Xiude Tu, Yongqian Xiong, Bang Wu, Lei Wang, Lei Cao, Jiayi Yang
Summary: The study utilizes a negative prechirp of broadband laser pulse to optimize electrooptic sampling and confirms significant enhancement of detection signals in ZnTe crystals.
IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY
(2021)
Article
Physics, Applied
Runmin Li, Haochen Tian, Takashi Kato, Akifumi Asahara, Kaoru Minoshima
Summary: A coherently synthesized 1550/1560 nm two-color EO comb is generated by modulating two continuous-wave lasers with common EO modulators and phase-locking their beat note. The phase noise of comb modes that accumulated from the RF synthesizer is effectively suppressed in our coherently synthesized two-color EO comb. A broader spectrum is demonstrated in a coherently synthesized 1535/1560 nm two-color EO comb, with a 60-nm total spectrum span. The coherently synthesized two-color EO combs are expected to be applied in coherent communication, spectroscopy, absolute distance measurement, etc.
APPLIED PHYSICS EXPRESS
(2023)
Article
Nanoscience & Nanotechnology
Zefeng Chen, Xuequan Chen, Li Tao, Kun Chen, Rui Zhang, Mingzhu Long, Emma Pickwell-MacPherson, Jianbin Xu
Summary: In this study, a graphene-based electrically reconfigurable polarization conversion technique was proposed for controlling the chiral polarization of THz waves. By electrically controlling the conductivity of graphene, a frequency-independent phase change was achieved, which enabled the manipulation of THz wave polarization. This research provides a new approach for designing THz modulators.
Article
Materials Science, Multidisciplinary
Abtin Ataei, Paul McManamon, Cullen Bradley, Ratnakar Neurgaonkar
Summary: This study designed an electro-optic laser beam steering device based on a SBN crystal and tested the performance of the crystal under different scenarios. The first and second EO effects and linear EO coefficients of the SBN75 crystal were measured and compared with literature values. The results showed that the SBN75 crystal exhibited a higher first EO effect at room temperature, a secondary EO effect below 8%, and the linear EO effect disappeared at 58°C.
Article
Physics, Multidisciplinary
Qiang-Shuang Li, Jing-Yi Wang, Chang-Ming Sun, Hai-Wei Du
Summary: This paper investigates the frequency response and pulse distortions induced by different thicknesses of GaSe crystal in electro-optic sampling (EOS) detection technology. The study finds that higher central frequencies of terahertz pulses lead to more significant distortions.
Article
Multidisciplinary Sciences
Souvik Biswas, Meir Y. Grajower, Kenji Watanabe, Takashi Taniguchi, Harry A. Atwater
Summary: The study demonstrates electrically reconfigurable polarization conversion using tri-layer black phosphorus integrated in a Fabry-Perot cavity, enabling spectrally broadband polarization control. The electrical tuning allows for a large fraction of the Poincare sphere to be covered with generated polarization states, and nearly half the Poincare sphere can be spanned with electrical tuning of the state of polarization conversion.
Article
Physics, Condensed Matter
Rukang Li
Summary: The electronic structure and vibrational spectra of ferroelectric LiNbO3 crystal (LN) are calculated using the CRYSTAL program. The obtained results include the bandgap, refractive indices, and nonlinear optical coefficients. It is found that the phonon vibrations in LN are asymmetric along the polar axis and the calculated frequencies strongly depend on displacement parameters. The calculated vibrational frequencies agree well with the measured ones, except in a certain frequency range.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Ga-Eun Yoon, Jin-Hong Seok, Uros Puc, Bong-Rim Shin, Woojin Yoon, Hoseop Yun, Dongwook Kim, In Cheol Yu, Fabian Rotermund, Mojca Jazbinsek, O-Pil Kwon
Summary: This study develops a new organic terahertz generator based on a catechol group, which suppresses phonons and improves performance. Compared to conventional organic crystals, this generator has smaller phonon amplitude and higher crystal density, resulting in the generation of broadband terahertz waves with high efficiency.
Article
Physics, Applied
V. B. Shirokov, P. E. Timoshenko, V. V. Kalinchuk
Summary: The electro-optic coefficients of ferroelectric materials were determined using Landau thermodynamic theory. It was proven that if the permittivity tensor is diagonal, certain ratios of the electro-optical coefficients are equal to ratios of its diagonal components. The influence of external electric field on the electro-optic coefficients of single-crystal barium titanate was studied and analyzed. It was found that the electro-optic coefficients for barium titanate are relatively high due to the non-linear response of dielectric susceptibility to electric field strength.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Optics
M. M. Jahanbakhshian, M. A. Kiani, M. Arshadi Pirlar, R. Karimzadeh
Summary: The electro-optic effect is an important mechanism for refractive index tuning, and this research measured the quadratic electro-optic coefficient for a graphene oxide film. The results showed a significantly higher coefficient compared to other materials, indicating the potential for improving devices based on this effect. The graphene oxide film's giant electro-optic Kerr coefficient can reduce power consumption and device complexity by requiring a lower electric field.
Article
Optics
Yaowen Hu, Mengjie Yu, Brandon Buscaino, Neil Sinclair, Di Zhu, Rebecca Cheng, Amirhassan Shams-Ansari, Linbo Shao, Mian Zhang, Joseph M. Kahn, Marko Loncar
Summary: Developments in integrated photonics have led to the emergence of stable, compact and broadband comb generators. The integrated electro-optic frequency comb presented in this research demonstrates a high conversion efficiency and a wide optical span, and can serve as an on-chip femtosecond pulse source. It also enables the simultaneous effects of electro-optic and third-order nonlinearity, paving the way for practical optical frequency comb generators and exploring new regimes of optical physics.
Article
Materials Science, Multidisciplinary
Lufan Du, Franz Roeder, Yun Li, Mostafa Shalaby, Burgard Beleites, Falk Ronneberger, Amrutha Gopal
Summary: The study utilized BNA crystals bonded on substrates of different thermal conductivity to generate THz radiation, with crystals bonded on sapphire substrate providing four times more THz yield than glass substrate. A pyrodetector and a single-shot EO diagnostic were used to measure the energy and temporal characteristics of the THz pulse. Systematic studies were conducted to select a suitable EO crystal for accurately determining the emitted THz spectrum from both substrates. This was followed by employing the THz source and single-shot EO detection scheme to measure the complex refractive index of window materials in the THz range.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2021)
Article
Optics
Wensheng Zhang, Linjun Li, Qiong Gao, Sheng Zhou
Summary: In this study, a diode-pumped electro-optically Q-switched Ho:GTO laser was presented, utilizing a langasite crystal as the EO Q-switch. The laser achieved a high peak power and excellent beam quality factors.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Optics
Yi Ji Tan, Wenhao Wang, Abhishek Kumar, Ranjan Singh
Summary: Valley photonic crystal (VPC) is a versatile platform in topological photonics, and this study explores the design of a composite interface junction to enable the topologically protected propagation of THz waves. The work illustrates the prospects and challenges of interfacial topological photonics in the design of broadband silicon topological waveguides.
Article
Physics, Condensed Matter
Lei Cao, Qiang Fu, Bang Wu, Yongqian Xiong
JOURNAL OF PHYSICS-CONDENSED MATTER
(2017)
Article
Optics
Lei Cao, Zhengya Yin, Huiting Xia
Summary: A phase-retrieval method based on Kramers-Kronig relations and independently measured transmission data as anchoring points was proposed to successfully extract the refractive index of optically thick and low-loss materials from FTIR spectra, in agreement with results from THz-TDS.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2021)
Article
Optics
Lei Cao, Huiting Xia, Shanshan JiA, Zhengya Yin
Summary: The performance of THz detectors based on 2DEG with subwavelength gratings coupler is critically dependent on the amplitude difference of electric field with positive and negative scattering orders. A method to enhance the current response of AlGaN/GaN material in the frequency range of 0 to 5 THz under oblique incidence of THz radiation with asymmetric gratings has been proposed. The study also compared the case of symmetric gratings to provide insights for theoretical and experimental optimization of grating-assisted THz detectors without electrical bias.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION
(2021)
Article
Engineering, Electrical & Electronic
Xiude Tu, Yongqian Xiong, Bang Wu, Lei Wang, Lei Cao, Jiayi Yang
Summary: The study utilizes a negative prechirp of broadband laser pulse to optimize electrooptic sampling and confirms significant enhancement of detection signals in ZnTe crystals.
IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY
(2021)
Article
Optics
Lei Cao, Shanshan Jia, Mark D. Thomson, Fanqi Meng, Hartmut G. Roskos
Summary: In a strongly coupled system working in the terahertz frequency range, a dual resonator (metamaterial and photonic crystal cavity) exhibits higher phase sensitivity but smaller frequency shift compared to a standalone metamaterial. The dielectric perturbation theory can guide and optimize the design of metamaterial-based sensors, and the enhanced phase sensitivity of the dual resonator may offer a new approach for improved terahertz sensors.
Article
Chemistry, Analytical
Zesen Zhou, Shanshan Jia, Lei Cao
Summary: A novel neural network model is proposed in this study to accurately obtain optical parameters of low-loss materials in a wide range of parameters. Validation with three different materials shows that this method has smaller errors compared to traditional iterative algorithms.
Article
Physics, Applied
Zesen Zhou, Zhilong Gan, Lei Cao
Summary: In this study, we investigated the effects of externally applied magnetic fields on the transmission properties of graphene patterned split ring resonator metamaterials in the terahertz region. We found that magnetic tuning can effectively modulate the resonance amplitude and frequency of the transmission component. Furthermore, combining magnetic and electrical tuning resulted in enhanced polarization conversion ratio and significant Faraday rotation angle in the metamaterials.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Optics
Fanqi Meng, Lei Cao, Aristeidis Karalis, Hantian Gu, Mark D. Thomson, Hartmut G. Roskos
Summary: This study reports on the strong coupling between a plasmonic dark mode and the photons in a photonic crystal cavity, in the terahertz frequency range. The coupling is mediated by a plasmonic bright mode, and the observed frequency splitting depends on the strength of the interaction between the two modes.
Article
Physics, Multidisciplinary
Lei Cao
JOURNAL OF PHYSICS COMMUNICATIONS
(2018)
Article
Physics, Fluids & Plasmas
Zhe Zhang, Bang Wu, Shali Yang, Ya Zhang, Dezhi Chen, Mingwu Fan, Wei Jiang
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2018)
