Author Affiliations
Abstract
1 State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
2 School of Electronic and Electrical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China
3 Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
4 Collaborative Innovation Center of Light Manipulations and Applications, Shandong Normal University, Jinan 250358, China
Whispering-gallery-mode (WGM) microresonators can greatly enhance light–matter interaction, making them indispensable units for frequency conversion in nonlinear optics. Efficient nonlinear wave mixing in microresonators requires stringent simultaneous optical resonance and phase-matching conditions. Thus, it is challenging to achieve efficient frequency conversion over a broad bandwidth. Here, we demonstrate broadband second-harmonic generation (SHG) in the x-cut thin-film lithium niobate (TFLN) microdisk with a quality factor above 107 by applying the cyclic quasi-phase-matching (CQPM) mechanism, which is intrinsically applicable for broadband operation. Broadband SHG of continuous-wave laser with a maximum normalized conversion efficiency of ∼15%/mW is achieved with a bandwidth spanning over 100 nm in the telecommunication band. Furthermore, broadband SHG of femtosecond lasers, supercontinuum lasers, and amplified spontaneous emission in the telecommunication band is also experimentally observed. The work is beneficial for integrated nonlinear photonics devices like frequency converters and optical frequency comb generator based on second-order nonlinearity on the TFLN platform.
lithium niobate whispering-gallery mode broadband second-harmonic generation cyclic quasi-phase matching Chinese Optics Letters
2024, 22(3): 031903
Author Affiliations
Abstract
1 School of Electronic and Electrical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China
2 State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
3 Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
4 Collaborative Innovation Center of Light Manipulation and Applications, Shandong Normal University, Jinan 250358, China
Optical frequency conversion based on the second-order nonlinearity () only occurs in anisotropic media (or at interfaces) and thus is intrinsically polarization-dependent. But for practical applications, polarization-insensitive or independent operation is highly sought after. Here, by leveraging polarization coupling and second-order nonlinearity, we experimentally demonstrate a paradigm of TE/TM polarization-independent frequency upconversion, i.e., sum frequency generation, in the periodically poled lithium niobate-on-insulator ridge waveguide. The cascading of quasi-phase-matched polarization coupling and nonlinear frequency conversion is exploited. With a proper transverse electric field, TE and TM mode fundamental waves can be frequency-upconverted with an equal efficiency in the frequency converter. The proposed method may find ready application in all-optical wavelength conversion and upconversion detection technologies.
frequency upconversion polarization coupling lithium niobate on insulator ridge waveguide cascading process Chinese Optics Letters
2023, 21(12): 121901
Author Affiliations
Abstract
1 Shanghai Jiao Tong University, School of Physics and Astronomy, State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai, China
2 Shanghai Research Center for Quantum Sciences, Shanghai, China
3 Shandong Normal University, Collaborative Innovation Center of Light Manipulations and Applications, Jinan, China
Scattering of waves, e.g., light, due to medium inhomogeneity is ubiquitous in physics and is considered detrimental for many applications. Wavefront shaping technology is a powerful tool to defeat scattering and focus light through inhomogeneous media, which is vital for optical imaging, communication, therapy, etc. Wavefront shaping based on the scattering matrix (SM) is extremely useful in handling dynamic processes in the linear regime. However, the implementation of such a method for controlling light in nonlinear media is still a challenge and has been unexplored until now. We report a method to determine the SM of nonlinear scattering media with second-order nonlinearity. We experimentally demonstrate its feasibility in wavefront control and realize focusing of nonlinear signals through strongly scattering quadratic media. Moreover, we show that statistical properties of this SM still follow the random matrix theory. The scattering-matrix approach of nonlinear scattering medium opens a path toward nonlinear signal recovery, nonlinear imaging, microscopic object tracking, and complex environment quantum information processing.
scattering matrix wavefront shaping nonlinear scattering medium nonlinear signal manipulation Advanced Photonics
2023, 5(4): 046010
Author Affiliations
Abstract
1 State Key Laboratory of Advanced Optical Communication Systems and Networks, University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, 200240 Shanghai, China
2 State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics (SIOM), CAS Center for Excellence in Ultra-Intense Laser Science, Chinese Academy of Sciences (CAS), 201800 Shanghai, China
3 Department of Physics and Astronomy, Shanghai Jiao Tong University, 200240 Shanghai, China
4 School of Physics and Electronic Science, East China Normal University, 200241 Shanghai, China
5 Department of Physics and Astronomy, College of Staten Island, the City University of New York, 10314 New York, USA
Transparency and perfect absorption are two contradictory terms; a perfect absorber never permits waves to transmit through. However, this statement only remains true in the linear regime, where the nonlinearity has been omitted and the physical system like the perfect absorber is not affected by the incoming waves. Here we experimentally demonstrate an intriguing self-induced transparency effect in a perfectly absorbing optical microcavity, which perfectly absorbs any incoming waves at the low power level, but allows a portion of waves to be transmitted at the higher power due to the nonlinear coupling between the fundamental and its second harmonic modes. Moreover, the asymmetric scattering nature of the microcavity enables a chiral and unidirectional reflection in one of the input ports, this leads to asymmetric and chiral coherent control of the perfect absorption states through phase varying. More importantly, such chiral behaviors also empower the chiral emission of second-harmonic generation with a high distinct ratio in the transparency state. These results pave the way for controllable transparency in a wide range of fields in optics, microwaves, acoustics, mechanics, and matter waves.
Author Affiliations
Abstract
1 State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
2 Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
3 Collaborative Innovation Center of Light Manipulation and Applications, Shandong Normal University, Jinan 250358, China
We design and fabricate an unbalanced Mach–Zehnder interferometer (MZI) via electron beam lithography and inductively coupled plasma etching on lithium niobate thin film. The single unbalanced MZI exhibits a maximum extinction ratio of 32.4 dB and a low extra loss of 1.14 dB at the telecommunication band. Furthermore, tunability of the unbalanced MZI by harnessing the thermo-optic and electro-optic effect is investigated, achieving a linear tuning efficiency of 42.8 pm/°C and 55.2 pm/V, respectively. The demonstrated structure has applications for sensing and filtering in photonic integrated circuits.
lithium niobate Mach–Zehnder interferometer electro-optic effect thermo-optic effect nanowaveguide Chinese Optics Letters
2022, 20(10): 101301
Author Affiliations
Abstract
1 Shanghai Jiao Tong University, School of Physics and Astronomy, State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai, China
2 Shanghai Research Center for Quantum Sciences, Shanghai, China
3 Shandong Normal University, Collaborative Innovation Center of Light Manipulation and Applications, Jinan, China
Constructions of synthetic lattices in modulated ring resonators attract growing attention to interesting physics beyond the geometric dimensionality, where complicated connectivities between resonant frequency modes are explored in many theoretical proposals. We implement experimental demonstration of generating a stub lattice along the frequency axis of light, in two coupled ring resonators of different lengths, with the longer one dynamically modulated. Such a synthetic photonic structure intrinsically exhibits the physics of flat band. We show that the time-resolved band structure read-out from the drop-port output of the excited ring is the intensity projection of the band structure onto a specific resonant mode in the synthetic momentum space, where gapped flat band, mode localization effect, and flat-to-nonflat band transition are observed in experiments and verified by simulations. This work provides evidence for constructing a synthetic stub lattice using two different rings, which, hence, makes a solid step toward experimentally constructing complicated lattices in multiple rings associated with synthetic frequency dimensions.
synthetic dimensions ring resonators dynamic modulation flat band Advanced Photonics
2022, 4(3): 036002
Author Affiliations
Abstract
1 State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
2 Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
3 Jinan Institute of Quantum Technology, Jinan 250101, China
4 Collaborative Innovation Center of Light Manipulations and Applications, Shandong Normal University, Jinan 250358, China
Orbital angular momentum (OAM) is a fundamental physical characteristic to describe laser fields with a spiral phase structure. Vortex beams carrying OAMs have attracted more and more attention in recent years. However, the wavefront of OAM light would be destroyed when it passes through scattering media. Here, based on the feedback-based wavefront shaping method, we reconstitute OAM wavefronts behind strongly scattering media. The intensity of light with desired OAM states is enhanced to 150 times. This study provides a method to manipulate OAMs of scattered light and is of great significance for OAM optical communication and imaging to overcome complex environment interference.
orbital angular momentum scattering wavefront shaping Chinese Optics Letters
2021, 19(10): 100101
1 区域光纤通信网与新型光通信系统国家重点实验室, 上海交通大学物理与天文学院, 上海 200240
2 上海量子科学研究中心, 上海 201315
3 济南量子技术研究院, 山东 济南 250101
4 山东师范大学光场调控及应用中心, 山东 济南 250358
铌酸锂晶体是一种综合性质优异的多功能光学材料。在过去几十年里,对铌酸锂晶体的研究一直是光学研究的热点之一。近年来发展起来的绝缘体上铌酸锂(LNOI),亦称为铌酸锂薄膜(LNTF),在光学领域被公认为是一项变革性技术。基于LNOI的集成光子器件让铌酸锂晶体又焕发了新生命,再次成为集成光子学的研究焦点。作为最优秀的非线性晶体之一,铌酸锂薄膜在频率转换方面是其他薄膜材料无法替代的。总结了基于铌酸锂薄膜的非线性频率转换最新研究进展,包括二阶非线性、三阶非线性、级联非线性和光学频率梳等,最后对LNOI平台上光子集成回路(PIC)的前景进行了展望。
光学器件 铌酸锂薄膜 非线性 频率变换 光子集成回路
Author Affiliations
Abstract
1 State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
2 Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900, China
3 IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
4 Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900, China
5 Collaborative Innovation Center of Light Manipulation and Applications, Shangdong Normal University, Jinan 250358, China
At the surfaces of crystals, linear susceptibility tensors would differ from their counterparts in the interior of the bulk crystal. However, this phenomenon has not been shown in a visible way yet. In previous researches, numerous types of nonlinear Cherenkov radiation based on different materials have been studied, while linear Cherenkov radiation is barely reported. We experimentally prove the generation of linear Cherenkov radiation on the potassium dihydrogen phosphate (KDP) crystal surface and theoretically analyze its phase-matching scheme. In our study, o-polarized light and e-polarized light can mutually convert through the linear Cherenkov process. According to this result, we figure out new nonzero elements at off-diagonal positions in the linear susceptibility tensor matrix at crystal surfaces, compared with the normal form of a bulk KDP.
linear susceptibility Cherenkov-type harmonic generation crystal boundary Chinese Optics Letters
2021, 19(3): 031901
1 区域光纤通信网与新型光通信系统国家重点实验室, 上海交通大学物理与天文学院, 上海 200240
2 上海量子科学研究中心, 上海 201315
3 济南量子技术研究院, 山东 济南 250101
4 山东师范大学光场调控及应用中心, 山东 济南 250358
5 江西师范大学物理系, 江西 南昌 330022
6 中国工程物理研究院上海激光等离子体研究所, 上海 201899
作为最早发现的非线性光学现象之一,非线性频率转换经过几十年的发展,从原理到应用均已不断成熟。非线性频率转换过程中新的相位匹配原理被不断提出和实现。除此之外,随着集成光学、结构光子学及量子光学等领域的不断发展,非线性频率转换在各领域的研究和应用又重新焕发活力,并发挥着不可替代的作用。本篇综述围绕非线性频率转换主题,突出非线性频率转换的新原理、新平台与新应用研究,并以本团队研究成果为基础,介绍相关领域的研究进展,主要分为以下几个方面:非线性界面相位匹配新原理;结构光场非线性谐波调控;铌酸锂薄膜集成非线性光学新平台;单光子频率转换、光量子接口等新应用。
非线性光学 非线性频率转换 结构光子学 集成光学 量子光学
