Author Affiliations
Abstract
1 Centre for Terahertz Waves and College of Precision Instrument and Optoeletronics Engineering, Tianjin University, Tianjin 300072, China
2 School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States
The dynamics of water within a nanopool of a reverse micelle is heavily affected by the amphiphilic interface. In this work, the terahertz (THz) spectra of cyclohexane/Igepal/water nonionic reverse micelle mixture are measured by THz time-domain spectroscopy and analyzed with two Debye models and complex permittivity of background with volume ratios. Based on the fitted parameters of bulk and fast water, the molar concentration of all kinds of water molecules and hydration water molecule number per Igepal molecule are calculated. We find that slow hydration water has the highest proportion in water when the radius parameter ω0<10, while bulk water becomes the main component when ω010. The feature radius ratio of nonhydrated and hydrated water to total water nanopool is roughly obtained from 0.39 to 0.85 with increasing ω0.
reverse micelle water dynamics THz spectroscopy 
Chinese Optics Letters
2024, 22(1): 013001
Author Affiliations
Abstract
1 Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, Tianjin University and the Key Laboratory of Optoelectronics Information and Technology (Ministry of Education), Tianjin 300072, China
2 Guangxi Key Laboratory of Optoelectronic Information Processing, School of Optoelectronic Engineering, Guilin University of Electronic Technology, Guilin 541004, China
3 School of Electronic and Computer Engineering, Oklahoma State University, Stillwater, OK 74078, USA
Plasmonic vortices confining orbital angular momentums to surface have aroused wide research interest in the last decade. Recent advances of near-field microscopes have enabled the study on the spatiotemporal dynamics of plasmonic vortices, providing a better understanding of optical orbital angular momentums in the evanescent wave regime. However, these works only focused on the objective characterization of plasmonic vortex and have not achieved subjectively tailoring of its spatiotemporal dynamics for specific applications. Herein, it is demonstrated that the plasmonic vortices with the same topological charge can be endowed with distinct spatiotemporal dynamics by simply changing the coupler design. Based on a near-field scanning terahertz microscopy, the surface plasmon fields are directly obtained with ultrahigh spatiotemporal resolution, experimentally exhibiting the generation and evolution divergences during the whole lifetime of plasmonic vortices. The proposed strategy is straightforward and universal, which can be readily applied into visible or infrared frequencies, facilitating the development of plasmonic vortex related researches and applications.
plasmonic vortex surface plasmon spatiotemporal dynamics optical orbital angular momentum 
Opto-Electronic Advances
2023, 6(4): 220133
Author Affiliations
Abstract
1 Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), Tianjin University, Tianjin, China
2 Guangxi Key Laboratory of Optoelectronic Information Processing, Guilin University of Electronic Technology, Guilin, China
3 School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, USA
Surface plasmons (SPs) are electromagnetic surface waves that propagate at the interface between a conductor and a dielectric. Due to their unique ability to concentrate light on two-dimensional platforms and produce very high local-field intensity, SPs have rapidly fueled a variety of fundamental advances and practical applications. In parallel, the development of metamaterials and metasurfaces has rapidly revolutionized the design concepts of traditional optical devices, fostering the exciting field of meta-optics. This review focuses on recent progress of meta-optics inspired SP devices, which are implemented by the careful design of subwavelength structures and the arrangement of their spatial distributions. Devices of general interest, including coupling devices, on-chip tailoring devices, and decoupling devices, as well as nascent SP applications empowered by sophisticated usage of meta-optics, are introduced and discussed.
surface plasmons metamaterials metasurfaces plasmonics metadevices 
Photonics Insights
2023, 2(1): R02
张伟丽 1,2,*史肖阳 1,2洪瑞金 1陈兴凤 1,2[ ... ]易葵 2
作者单位
摘要
1 上海理工大学光电信息与计算机工程学院,上海 200093
2 中国科学院上海光学精密机械研究所薄膜光学实验室,上海 201800
高透过率的窗口材料是光电系统高精度和稳定性的重要保障。金刚石材料集优良的光学特性以及高热导率、低热膨胀系数等特性于一身,是性能优异的宽波段窗口材料。但金刚石在可见光及红外波段的高折射率限制了它的进一步应用,构筑减反射微纳结构抑制金刚石表面反射损耗是较为有效的方法之一。本文综述了近年来金刚石减反射微纳结构的研究进展,着重介绍了微纳结构的减反射机理以及激光加工和离子刻蚀两类加工方式的基本原理及工艺条件,总结了两种方式制备的表面微纳结构对金刚石透过率的影响,对比了各类制备技术的优缺点,并简单介绍了金刚石的应用前景,旨在为相关领域的研究人员提供技术参考。
表面光学 金刚石 微纳结构 减反射机理 激光加工 离子刻蚀 应用前景 surface optics diamond micro-nano structures anti-reflection mechanism laser processing ion etching application prospect 
中国激光
2023, 50(8): 0802402
Author Affiliations
Abstract
1 Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, Tianjin University and Key Laboratory of Optoelectronics Information and Technology (Ministry of Education)https://ror.org/012tb2g32, Tianjin 300072, China
2 Guangxi Key Laboratory of Optoelectronic Information Processing, School of Optoelectronic Engineering, Guilin University of Electronic Technology, Guilin 541004, China
3 School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, USA
4 e-mail: quanxu@tju.edu.cn
5 e-mail: gjq@tju.edu.cn
Perfect optical vortices (POVs), characterized as a ring radius independent of topological charge (TC), possess extensive application in particle manipulation and optical communication. At present, the complex and bulky optical device for generating POVs has been miniaturized by leveraging the metasurface, and either spin-dependent or spin-independent POV conversions have been further accomplished. Nevertheless, it is still challenging to generate superposed POVs for incidences with orthogonal circular polarization. Here, a spin-multiplexed all-dielectric metasurface method for generating superposed POVs in the terahertz frequency range is proposed and demonstrated. By using the multiple meta-atom comprised structure as the basic unit, the complex amplitude of two superposed POVs is modulated, decoupled, and subsequently encoded to left- and right-handed circular polarization incidences. Furthermore, two kinds of metasurfaces are fabricated and characterized to validate this controlling method. It is demonstrated that the measured intensity and phase distributions match well with the calculation of the Rayleigh–Sommerfeld diffraction integral, and the radius of superposed POVs is independent of TCs. This work provides promising opportunities for developing ultracompact terahertz functional devices applied to complex structured light generation and terahertz communication, and exploring sophisticated spin angular momentum and orbital angular momentum interactions like the photonic spin-Hall effect.
Photonics Research
2023, 11(3): 431
Author Affiliations
Abstract
1 Fiber Optics Research Centre, School of Information and Communication Engineering, University of Electronic Science and Technology of Chinahttps://ror.org/04qr3zq92, Chengdu 611731, China
2 e-mail: yjrao@uestc.edu.cn
3 e-mail: wl_zhang@uestc.edu.cn
Raman fiber lasers (RFLs) have broadband tunability due to cascaded stimulated Raman scattering, providing extensive degrees of freedom for spectral manipulation. However, the spectral diversity of RFLs depends mainly on the wavelength flexibility of the pump, which limits the application of RFLs. Here, a spectrally programmable RFL is developed based on two-dimensional spatial-to-spectral mapping of light in multimode fibers (MMFs). Using an intracavity wavefront shaping method combined with genetic algorithm optimization, we launch light with a selected wavelength(s) at MMF output into the active part of the laser for amplification. In contrast, the light of undesired wavelengths is blocked. We demonstrate spectral shaping of the high-order RFL, including a continuously tunable single wavelength and multiple wavelengths with a designed spectral shape. Due to the simultaneous control of different wavelength regions, each order of Raman Stokes light allows flexible and independent spectral manipulation. Our research exploits light manipulation in a fiber platform with multi-eigenmodes and nonlinear gain, mapping spatial control to the spectral domain and extending linear light control in MMFs to active light emission, which is of great significance for applications of RFLs in optical imaging, sensing, and spectroscopy.
Photonics Research
2023, 11(1): 20
Author Affiliations
Abstract
The recent era of fast optical manipulation and optical devices owe a lot to exciton-polaritons being lighter in mass, faster in speed and stronger in nonlinearity due to hybrid light-matter characteristics. The room temperature existence of polaritons in two dimensional materials opens up new avenues to the design and analysis of all optical devices and has gained the researchers attention. Here, spin-selective optical Stark effect is introduced to form a waveguide effect in uniform community of polaritons, and is used to realize polarization modulation of polaritons. The proposed device basically takes advantage of the spin-sensitive properties of optical Stark effect of polaritons inside the WS2 microcavity so as to guide different modes and modulate polarization of polaritons. It is shown that polaritonic wavepacket of different mode profiles can be generated by changing intensity of the optical Stark beam and the polarization of polaritons can be controlled and changed periodically along the formed waveguide by introduction birefringence that is sensitive to polarization degree of the optical Stark beam.The recent era of fast optical manipulation and optical devices owe a lot to exciton-polaritons being lighter in mass, faster in speed and stronger in nonlinearity due to hybrid light-matter characteristics. The room temperature existence of polaritons in two dimensional materials opens up new avenues to the design and analysis of all optical devices and has gained the researchers attention. Here, spin-selective optical Stark effect is introduced to form a waveguide effect in uniform community of polaritons, and is used to realize polarization modulation of polaritons. The proposed device basically takes advantage of the spin-sensitive properties of optical Stark effect of polaritons inside the WS2 microcavity so as to guide different modes and modulate polarization of polaritons. It is shown that polaritonic wavepacket of different mode profiles can be generated by changing intensity of the optical Stark beam and the polarization of polaritons can be controlled and changed periodically along the formed waveguide by introduction birefringence that is sensitive to polarization degree of the optical Stark beam.
Stark beam polaritons modulator TMDs polarization degree 
Opto-Electronic Advances
2022, 5(11): 200066
Yi Liu 1Chunmei Ouyang 1,5,*Quan Xu 1Xiaoqiang Su 2,6,*[ ... ]Weili Zhang 4,7,*
Author Affiliations
Abstract
1 Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronic Information Technology (Ministry of Education of China), Tianjin University, Tianjin 300072, China
2 Institute of Solid State Physics, College of Physics and Electronic Science, Shanxi Province Key Laboratory of Microstructure Electromagnetic Functional Materials, Shanxi Datong University, Datong 037009, China
3 Nonlinear Physics Centre, Australian National University, Canberra, ACT 2601, Australia
4 School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, USA
5 e-mail: cmouyang@tju.edu.cn
6 e-mail: xiaoqiang.su@sxdtdx.edu.cn
7 e-mail: weili.zhang@okstate.edu
Recent moiré configurations provide a new platform for tunable and sensitive photonic responses, as their enhanced light–matter interactions originate from the relative displacement or rotation angle in a stacking bilayer or multilayer periodic array. However, previous findings are mostly focused on atomically thin condensed matter, with limitations on the fabrication of multilayer structures and the control of rotation angles. Structured microwave moiré configurations are still difficult to realize. Here, we design a novel moiré structure, which presents unprecedented capability in the manipulation of light–matter interactions. Based on the effective medium theory and S-parameter retrieval process, the rotation matrix is introduced into the dispersion relation to analyze the underlying physical mechanism, where the permittivity tensor transforms from a diagonal matrix to a fully populated one, whereas the permeability tensor evolves from a unit matrix to a diagonal one and finally becomes fully filled, so that the electromagnetic responses change drastically as a result of stacking and rotation. Besides, the experiment and simulation results reveal hybridization of eigenmodes, drastic manipulation of surface states, and magic angle properties by controlling the mutual rotation angles between two isolated layers. Here, not only a more precisely controllable bilayer hyperbolic metasurface is introduced to moiré physics, the findings also open up a new avenue to realize flat bands at arbitrary frequencies, which shows great potential in active engineering of surface waves and designing multifunctional plasmonic devices.
Photonics Research
2022, 10(9): 2056
Author Affiliations
Abstract
1 Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, Tianjin University, and Key Laboratory of Optoelectronics Information and Technology, Ministry of Education, Tianjin 300072, China
2 Nonlinear Physics Centre, Australian National University, Canberra, ACT 2601, Australia
3 Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
4 School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, USA
5 e-mail: gjq@tju.edu.cn
6 e-mail: Quanlong.Yang@anu.edu.au
7 e-mail: conglq@sustech.edu.cn
8 e-mail: weili.zhang@okstate.edu
Metasurface-empowered bound state in the continuum (BIC) provides a unique route for fascinating functional devices with infinitely high quality factors. This method is particularly attractive to the terahertz community because it may essentially solve the deficiencies in terahertz filters, sensors, lasers, and nonlinear sources. However, most BIC metasurfaces are limited to specified incident angles that seriously dim their application prospects. Here, we propose that a dual-period dielectric metagrating can support multiple families of BICs that originate from guided mode resonances in the dielectric grating and exhibit infinite quality factors at arbitrarily tilted incidence. This robustness was analyzed based on the Bloch theory and verified at tilted incident angles. We also demonstrate that inducing geometric asymmetry is an efficient way to manipulate the leakage and coupling of these BICs, which can mimic the electromagnetically induced transparency (EIT) effect in our dual-period metagrating. In this demonstration, a slow-light effect with a measured group delay of 117 ps was achieved. The incidence-insensitive BICs proposed here may greatly extend the application scenarios of the BIC effect. The high Q factor and outstanding slow-light effect in the metagrating show exciting prospects in realizing high-performance filters, sensors, and modulators for prompting terahertz applications.
Photonics Research
2022, 10(3): 03000810
Author Affiliations
Abstract
1 Tianjin University, Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronic Information Technology (Ministry of Education of China), Tianjin, China
2 Shanxi Datong University, Institute of Solid State Physics and College of Physics and Electronic Science, Shanxi Province Key Laboratory of Microstructure Electromagnetic Functional Materials, Datong, China
3 Wuhan University of Technology, School of Information Engineering, Wuhan, China
4 Tianjin Normal University, College of Physics and Materials Science, Tianjin, China
5 City University of New York, Advanced Science Research Center, Photonics Initiative, New York, United States
6 City University of New York, Graduate Center, Physics Program, New York, United States
7 University of Hong Kong, Faculty of Science, Department of Physics, Hong Kong, China
8 University of Hong Kong, Department of Electrical and Electronic Engineering, Hong Kong, China
9 Guilin University of Electronic Technology, Guangxi Key Laboratory of Optoelectronic Information Processing, School of Optoelectronic Engineering, Guilin, China
10 Oklahoma State University, School of Electrical and Computer Engineering, Stillwater, Oklahoma, United States
Metasurfaces have enabled the realization of several optical functionalities over an ultrathin platform, fostering the exciting field of flat optics. Traditional metasurfaces are achieved by arranging a layout of static meta-atoms to imprint a desired operation on the impinging wavefront, but their functionality cannot be altered. Reconfigurability and programmability of metasurfaces are the next important step to broaden their impact, adding customized on-demand functionality in which each meta-atom can be individually reprogrammed. We demonstrate a mechanical metasurface platform with controllable rotation at the meta-atom level, which can implement continuous Pancharatnam–Berry phase control of circularly polarized microwaves. As the proof-of-concept experiments, we demonstrate metalensing, focused vortex beam generation, and holographic imaging in the same metasurface template, exhibiting versatility and superior performance. Such dynamic control of electromagnetic waves using a single, low-cost metasurface paves an avenue towards practical applications, driving the field of reprogrammable intelligent metasurfaces for a variety of applications.
reprogrammable metasurfaces Pancharatnam–Berry phase mechanical metasurfaces microwaves 
Advanced Photonics
2022, 4(1): 016002

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