2021

• Record 421 of
  
  Title:High performance parametric spectro-temporal analyzer assisted by a soliton microcomb
  
  Author(s):Hu, Hao(1); Yang, Ningning(1); Wang, Weiqiang(2,3); Chen, Liao(1); Zhang, Chi(1); Zhang, Wenfu(2); Zhang, Xinliang(1)
  Source: Asia Communications and Photonics Conference, ACP  Volume: 2021-October  Issue:   DOI: null  Published: 2021  
  Abstract:We experimentally demonstrated a high performance parametric spectro-temporal analyzer. Assisted by a soliton microcomb, it achieved a resolution of 4 pm, a bandwidth of 13 nm and the tunable frame rate from kHz to MHz. © Optica Publishing Group 2021
  Accession Number: 20221612005096
• Record 422 of
  
  Title:Optical vortex lattice: An exploitation of orbital angular momentum
  
  Author(s):Zhu, Liuhao(1,2); Tang, Miaomiao(1); Li, Hehe(1); Tai, Yuping(3); Li, Xinzhong(1,2)
  Source: Nanophotonics  Volume: 10  Issue: 9  DOI: 10.1515/nanoph-2021-0139  Published: July 1, 2021  
  Abstract:Generally, an optical vortex lattice (OVL) is generated via the superposition of two specific vortex beams. Thus far, OVL has been successfully employed to trap atoms via the dark cores. The topological charge (TC) on each optical vortex (OV) in the lattice is only ±1. Consequently, the orbital angular momentum (OAM) on the lattice is ignored. To expand the potential applications, it is necessary to rediscover and exploit OAM. Here we propose a novel high-order OVL (HO-OVL) that combines the phase multiplication and the arbitrary mode-controllable techniques. TC on each OV in the lattice is up to 51, which generates sufficient OAM to manipulate microparticles. Thereafter, the entire lattice can be modulated to desirable arbitrary modes. Finally, yeast cells are trapped and rotated by the proposed HO-OVL. To the best of our knowledge, this is the first realization of the complex motion of microparticles via OVL. Thus, this work successfully exploits OAM on OVL, thereby revealing potential applications in particle manipulation and optical tweezers. © 2021 Liuhao Zhu et al., published by De Gruyter, Berlin/Boston 2021.
  Accession Number: 20212510524259
• Record 423 of
  
  Title:Dispersed pulses created by aperiodic binary spectral phase jump and applications for pulse shaping
  
  Author(s):Liu, Xin(1,2); Wang, Hushan(1,2); Cao, Huabao(1,2,3); Yuan, Hao(1,2); Huang, Pei(1); Wang, Yishan(1,2); Zhao, Wei(1,2); Fu, Yuxi(1,2)
  Source: Optics Express  Volume: 29  Issue: 8  DOI: 10.1364/OE.419450  Published: April 12, 2021  
  Abstract:Inspired by pulse-pair generation with periodic phase jump, the generation of dispersed pulses with aperiodic binary spectral phase jump (ABSPJ) is proposed and theoretically investigated. It is presented by the numerical simulations that two dispersed pulses can be generated by ABSPJ of π. The dispersion of one pulse is opposite to the other and can be tuned freely with engineering of the phase jump. The generated dispersed pulse-pair is potentially of great interest for various applications, such as two-dimensional spectroscopy, double pulses laser-wakefield acceleration (LWFA) and chirp management in dual-chirped optical parametric amplification (DC-OPA) system to generate TW single-cycle mid-infrared (MIR) pulses. Furthermore, a pulse shaper configured as a micro-electro-mechanical systems (MEMS) located at the Fourier plane of a 4-f dispersion-free compressor is suggested and the implementation in a high repetition optical parametric chirped pulse amplification (OPCPA) system with picosecond pump has been numerically studied. The simulations showed that MEMS of 900 pixels is enough to pre-compensate TOD of 200000 fs3 for a pulse of 20 fs. Because pixel with only two piston-levels is necessary for such MEMS, the pulse shaper is expected to be compact and reliable. © 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
  Accession Number: 20211710242449
• Record 424 of
  
  Title:Equal spacing control of particle via cycloidal beam (Invited)
  
  Author(s):Zhu, Liuhao(1); Qin, Xueyun(1); Tai, Yuping(3); Li, Xinzhong(1,2)
  Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering  Volume: 50  Issue: 9  DOI: 10.3788/IRLA20210380  Published: September 25, 2021  
  Abstract:The discovery of orbital angular momentum (OAM) opens up a new way for the study of optical tweezers. However, the size and shape of biological cells cannot be exactly the same, when the beam with OAM manipulates the particles. So, the uneven velocity of the particles will lead to uncontrollable spacing between the particles when it carries out operations such as rotation. To solve the problem, a cycloid beam with rich regulation modes was proposed by using an arbitrary curve shaping technique and adding curvature control parameters to the traditional cycloid formula. The OAM and gradient force of the cycloid beam was theoretically analyzed, and the possibility of solving the problem was theoretically analyzed. Finally, the start and stop of particles in the process of motion were realized in the experiment, and the three particles were successfully manipulated to rotate at the same distance. The experimental results show that the error of the distance variation of the three particles during the whole rotation process can be maintained at the nanometer level. The work paves the way for future applications of light to capture and manipulate a variety of particles in other fields, particularly in the biological sciences. © 2021, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.
  Accession Number: 20214111012348
• Record 425 of
  
  Title:Radio frequency spectrum analyzer with a 5 THz bandwidth based on nonlinear optics in a CMOS-compatible high-index doped silica waveguide
  
  Author(s):Li, Yuhua(1,2); Kang, Zhe(3,4); Zhu, Kun(2); Ai, Shiqi(2); Wang, Xiang(5); Davidson, Roy R.(5); Wu, Yan(1); Morandotti, Roberto(6); Little, Brent E.(7); Moss, David J.(8); Chu, Sai Tak(2)
  Source: arXiv  Volume:   Issue:   DOI: null  Published: March 18, 2021  
  Abstract:We report an all-optical radio-frequency (RF) spectrum analyzer with a bandwidth greater than 5 terahertz (THz), based on a 50-cm long spiral waveguide in a CMOS-compatible high-index doped silica platform. By carefully mapping out the dispersion profile of the waveguides for different thicknesses, we identify the optimal design to achieve near zero dispersion in the C-band. To demonstrate the capability of the RF spectrum analyzer, we measure the optical output of a femtosecond fiber laser with an ultrafast optical RF spectrum in the terahertz regime. © 2021, CC BY.
  Accession Number: 20210083991
• Record 426 of
  
  Title:Excitation of high-quality orbital angular momentum vortex beams in an adiabatically helical-twisted single-mode fiber
  
  Author(s):Ren, Kaili(1,2); Ren, Liyong(2,3); Liang, Jian(2,3); Yang, Li(4); Xu, Jie(1); Han, Dongdong(1); Wang, Yongkai(1,3); Liu, Jihong(1); Dong, Jun(1); He, Hanyu(1); Zhang, Wenfei(2,5)
  Source: Optics Express  Volume: 29  Issue: 6  DOI: 10.1364/OE.419668  Published: March 15, 2021  
  Abstract:A novel method to control the parameters of a chiral fiber grating structure is proposed. Mode couplings are controlled in real time during the twisting fabrication process. This chiral grating structure can satisfy the phase-matching condition for generating high-quality orbital angular momentum (OAM) beams, with an order mode of conversion efficiency over 99.9%. Both theoretical analysis and experimental results of this OAM mode conversion have been investigated, with good agreement. The results demonstrate a dual-OAM beam converter with a charge of ?}1 for the right- A nd left-handed CLPGs, respectively. The high-quality OAM beam generated in this twisted single-mode fiber process may find excellent applications in optical communications. © 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.
  Accession Number: 20211010057464
• Record 427 of
  
  Title:Localized gap modes of coherently trapped atoms in an optical lattice
  
  Author(s):CHEN, ZHIMING(1,2); ZENG, JIANHUA(3)
  Source: Optics Express  Volume: 29  Issue: 3  DOI: 10.1364/OE.412554  Published: February 1, 2021  
  Abstract:We theoretically investigate one-dimensional localized gap modes in a coherent atomic gas where an optical lattice is formed by a pair of counterpropagating far-detuned Stark laser fields. The atomic ensembles under study emerge as Λ-type three-level configuration accompanying the effect of electromagnetically induced transparency (EIT). Based on Maxwell- Bloch equations and the multiple scales method, we derive a nonlinear equation governing the spatial-temporal evolution of the probe-field envelope. We then uncover the formation and properties of optical localized gap modes of two kinds, such as the fundamental gap solitons and dipole gap modes. Furthermore, we confirm the (in)stability regions of both localized gap modes in the respective band-gap spectrum with systematic numerical simulations relying on linear-stability analysis and direct perturbed propagation. The predicted results may enrich the nonlinear horizon to the realm of coherent atomic gases and open up a new door for optical communication and information processing. © 2021 Optical Society of America.
  Accession Number: 20210509837138
• Record 428 of
  
  Title:Properties of Optical Vortex Lattice Generated via Multiple Plane Wave Interference
  
  Author(s):Qin, Xueyun(1,2); Zhu, Liuhao(1); Tai, Yuping(3); Tang, Jie(2); Li, Xinzhong(1,2)
  Source: Guangxue Xuebao/Acta Optica Sinica  Volume: 41  Issue: 21  DOI: 10.3788/AOS202141.2126001  Published: November 10, 2021  
  Abstract:Multiple plane wave interference (MPWI) is a typical method to produce an optical vortex lattice (OVL). In this letter, via defining the wave vector space coordinate system, a modulating method of OVL with MPWI is proposed, the OVLs generated by four plane wave and five plane wave interference are simulated, the gradient force and energy flow of the OVL are calculated, and its application in the field of particle manipulation is analyzed. Accordingly, a more flexible and richer optical field distribution is obtained via adjusting the size of the partial wave vector and the angle of the rotation wave vector. Finally, by analyzing the gradient force and energy flow, it is found that the light field with a specific purpose can be generated by this method when manipulating particles. This study enriches the diversity of modes of OVL generated by MPWI and provides a novel idea for the study of OVL based on MPWI. © 2021, Chinese Lasers Press. All right reserved.
  Accession Number: 20220911713137
• Record 429 of
  
  Title:Development of High-Power Ultrafast Fiber Laser Technology
  
  Author(s):Liu, Yizhou(1); Qiao, Wenchao(1); Gao, Kong(1,2); Xu, Rong(1); Feng, Tianli(1,2); Zhang, Meng(1); Li, Xun(3); Liang, Yangyang(1,2); Li, Tao(1,2)
  Source: Zhongguo Jiguang/Chinese Journal of Lasers  Volume: 48  Issue: 12  DOI: 10.3788/CJL202148.1201003  Published: June 25, 2021  
  Abstract:Significance: In 1960, after the invention of the first ruby laser, fast-developed solid-state, fiber, gas, and semiconductor lasers provided great support for the research and development of multiple applications, such as optical communication, industrial processing and manufacturing, military and national defense, and state-of-the-art scientific research. Fiber lasers with good heat dissipation characteristics, excellent transverse mode, high amplification efficiency, compact laser construction, and less costs have become the first choice in developing next generation high-power ultrafast lasers. Fiber lasers can achieve long-term operation stability with good beam quality under above-average power because of their waveguide characteristics and large specific gain fiber surface area. High-power ultrafast fiber lasers usually contain four modules, ultrafast fiber oscillators, optical parameters management, ultrafast fiber amplifiers, and nonlinear compression. Ultrafast fiber oscillators provide seed lasers to achieve high-power ultrafast fiber lasers. A qualified mode-locked fiber oscillator has long-term stability and a proportional repetition shared rate corresponding to the requirements of high-power fiber amplifications. Optical parameters management plays a key role in inhibiting uncompensated nonlinear effects and enabling high-energy pulse output with good pulse quality after optical pulse stretching, high power fiber amplification, and optical pulse compression. The ultrafast fiber amplifiers are key modules to scale up the average power of the stretched-signal pulses. Unfortunately, the uncompensated nonlinear phase introduced by the high-peak power of the signal pulse distorts the pulse profile during its propagation in the fiber system. Based on the well-managed optical parameters of fiber lasers, the well-known fiber amplification methods, such as chirped-pulse, divided-pulse, and pre-chirp managed amplifications are making a significant breakthrough in achieving high-power ultrafast fiber lasers. The pulse duration after high-power fiber amplification is hundreds of femtoseconds limited by the gain-narrowing effect. Therefore, a further cascaded nonlinear compression stage is needed for shortening the amplified pulses, which can realize single/few optical cycle pulse duration to fulfill the requirements of the state-of-the-art physical experiments. With their excellent optical characteristics, the fast-developing high-power fiber lasers can play an increasingly important role in multiple applications. Progress Progress in developing ultrafast fiber oscillators, optical parameters management, ultrafast fiber amplifiers, and nonlinear compression are summarized in this paper, and latest published results are discussed by illustrating the advantages and disadvantages of different methods. The highest repetition rate of fiber oscillators reported using the method of nonlinear polarization rotation is 1 GHz provided to be useful in astronomical optical frequency comb, pulse stacking, and the cavity-enhanced high harmonic generation. The highest average output power and pulse energies are 1.98 W and 684 nJ, which are achieved with the nonlinear loop mirror mode-locking scheme, respectively. Applying a semiconductor saturable absorber mirror to the mode-locked fiber laser can generate an output mode-locked laser with the repetition rate range of 10 kHz1 GHz and sub-μJ pulse energy. As a newly invented mode-locked method, Mamyshev mode-locked fiber laser has attracted attention for its broadband optical spectrum, high-pulse energy output, and high-peak power. As the seeder for a high-power ultrafast fiber laser system, further efforts need to be taken in developing a more stable fiber oscillator with better parameters. Relying on optical parameter management, current ultrafast fiber amplifiers are realized with different amplification methods, such as chirped-pulse, divided-pulse, and pre-chirp managed amplifications. The highest average output power of 830 W at 1 μm was reported by applying the chirped-pulse amplification. Limited by the transverse mode instability and thermal damage threshold, there is one research direction for further improvement that can be realized by searching for new gain materials with better optical performances. Combining the chirped-pulse and multi-channel divided-pulse amplifications, the highest average output power of 10.4 kW was obtained in a 12-channel fiber laser amplifier. 36 fs mode-locked pulses with 100 W average power were achieved with the method of pre-chirp managed amplification, avoiding adding a cascaded nonlinear compression stage. Apart from the aforementioned amplification methods, coherent pulse stacking method is also an efficient way in realizing ultrafast fiber laser with high-pulse energy. Pulse energy of 10 mJ was achieved with the coherent pulse stacking based on the high-power ultrafast fiber laser source. It is difficult to realize sub-100 fs or even shorter pulse durations in a high-power fiber chirped pulse amplification system due to the gain-narrowing effect. Therefore, a further nonlinear compression stage is necessary to satisfying the state-of-the-art applications, requiring short pulse duration. Multipass cells with quartz sheet/noble gas and noble-gas-filled hollow-core fibers are two common constructions in building the nonlinear compression stage, which are illustrated in the nonlinear compression section of this paper. The pulse duration can be compressed to 22 fs, and a pulse energy of 15.6 μJ was realized in the multipass cell construction. Using the noble-gas-filled hollow-core fibers, pulse duration was shortened to approximately 4.3 fs corresponding to a 1.6 optical cycle with a pulse energy of 1 mJ. Conclusions and Prospect In this paper, the high-power ultrafast fiber laser systems are introduced. Research and development status of high-power ultrafast fiber lasers are illustrated along with introducing principles and internal relations of four fundamental modules of ultrafast fiber oscillators, optical parameters management, ultrafast fiber amplifiers, and nonlinear compression. Depending on the fast-developing requirements from multiple state-of-the-art applications, more efforts need to be taken. Further research directions in developing high-power ultrafast fiber lasers have prospected. One promising way is investigating new fiber materials with promising better optical parameters compared to fused silica. Further, making contributions in developing the aforementioned fiber amplification methods is also an efficient way in developing fiber lasers with above-average power, higher-pulse energy, and shorter pulse duration. Newly designed optical fiber amplification methods still need to be invented by carefully considering the optical characteristics of fiber gain material and theoretical nonlinear optical conditions. High-power ultrafast fiber lasers can play a key role in multiple state-of-the-art applications relying on the development of searching for more functional fiber gain materials, optimizing aforementioned amplification techniques, and inventing new methods in amplifying high-power ultrafast fiber lasers. © 2021, Chinese Lasers Press. All right reserved.
  Accession Number: 20213510824261
• Record 430 of
  
  Title:Optical system design of polarization imaging spectrometer based on aperture division
  
  Author(s):Chang, Lingying(1); Pan, Qian(1); Qiu, Yuehong(2); Zhao, Baochang(2)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 11761  Issue:   DOI: 10.1117/12.2586810  Published: 2021  
  Abstract:Based on the principle of acousto-optic tunable filter and aperture division, the new method that can obtain a high spectral full polarization and image information was proposed. It was improved the accuracy of target detection and object recognition by this method. The Optical system of polarization imaging spectrometer based on aperture divisionandacousto-optic tunable filter was designed in this paper, which was used in the 2.16-meter telescope and spectral range is 450-900 nm.First,the working principle of polarization imaging spectrometer based on aperture division was introduced.Then, the design scheme of optical system and the principle of information acquisition were studied.Finally, the design parameters were assigned and theoptical systems were designed.The whole system MTF reach 0.6 in 32lp/mm.The olarization imaging spectrometer based on aperture division can improve the observation capacity. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
  Accession Number: 20210509874631
• Record 431 of
  
  Title:Optimization of the epitaxial structure of low-loss 885nm high-power laser diodes
  
  Author(s):Wu, Shun-Hua(1,2); Li, Te(2); Wang, Dan(2); Yu, Xue-Cheng(2); Wang, Zhen-Fu(2); Liu, Guo-Jun(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 11907  Issue:   DOI: 10.1117/12.2602879  Published: 2021  
  Abstract:Aiming at the epitaxial structure of the high-power 885nm laser diodes, the factors limiting the further increase of the output power and the power conversion efficiency were investigated. According to the analysis, the epitaxial structure of the laser diodes was optimized, and the influence of the waveguide layer thickness on the carrier absorption loss and the series resistance was theoretically simulated. The results showed that the asymmetric waveguide structure with the thickness ratio of the N-side and the P-side of 6:4 can reduce the carrier absorption loss to the greatest extent. Based on the simulation results, the 885nm laser bars with the optimized epitaxial structure were fabricated and tested under the ambient temperature of 25 in a quasi-continuous wave mode of 250μs and 200Hz. The slope efficiency reaches 1.26W/A, while the series resistance is only 1.2mω. The power of 277.6W is achieved at 250A injection current and the maximum power conversion efficiency exceeds 64%. © 2021 SPIE.
  Accession Number: 20215111372727
• Record 432 of
  
  Title:Optical separation and discrimination of chiral particles by vector beams with orbital angular momentum
  
  Author(s):Li, Manman(1); Yan, Shaohui(1); Zhang, Yanan(1); Chen, Xu(1); Yao, Baoli(1,2)
  Source: Nanoscale Advances  Volume: 3  Issue: 24  DOI: 10.1039/d1na00530h  Published: December 21, 2021  
  Abstract:Chirality describes a reduced symmetry and abounds in nature. The handedness-dependent response usually occurs only when a chiral object interacts with another chiral entity. Light carrying orbital angular momentum (OAM) is inherently chiral due to the helical wave front. Here, we put forward a scheme that enables optical separation and simultaneous discrimination of single chiral particles using focused vector beams with OAM. Such focused vector vortex beams carrying radial-splitting optical chirality can selectively trap one enantiomer inside or outside the intensity maxima depending on the sign of the OAM. The particles with different chirality parameters can be trapped on different orbits and experience enhanced orbital motion. Moreover, the magnitude of OAM as well as the size of particle plays an important role in the chiral separation and discrimination. In addition to particle manipulation, the discussion of OAM in chiral light-matter interactions has potential application in, for example, optical enantioseparation or chiral detection. This journal is © The Royal Society of Chemistry.
  Accession Number: 20215011329574