1 浙江大学光电科学与工程学院光及电磁波研究中心，浙江 杭州 310058
2 浙江大学上海高等研究院，上海 201203
近年来，随着超材料研究的发展，中红外波段的吸波超表面得到了快速发展，其应用潜力也不断被发掘。本文首先介绍了不同类型的中红外吸波超表面及其工作机理，然后回顾了在热辐射源、热隐身和探测器等应用中吸波超表面的应用方式和优势，最后总结现有的挑战并对将来的发展进行了展望。
探测器 中红外波段 超表面 完美吸收 热辐射 热隐身 光学学报
2022, 42(17): 1704001
1 国家光学仪器工程研究中心 浙江大学光及电磁波研究中心，浙江 杭州 310058
2 浙江大学 宁波研究院，浙江 宁波 315100
海洋是涵盖超过70%地球表面的连续海水，发展先进的海洋生物光学监测手段对海洋生态系统的保护至关重要。文中综述了笔者团队在小型高光谱图谱仪与激光雷达系统搭建及其在海洋生物检测等应用上的部分近期工作。图谱仪方面介绍了不同空间扫描方式的高光谱图谱仪在透射、反射及荧光等不同工作模式下，对数种藻类、斑马鱼等海洋生物进行了图谱检测，并且基于图谱数据结合机器学习算法实现了微藻种类的精准分类和藻类生长周期的准确预测；在激光雷达方面详述了使用非弹性高光谱沙姆激光雷达系统在实验室和近岸实地环境进行了多次水生生物的测量实验，成功获取其荧光高光谱，证明了非弹性高光谱沙姆激光雷达系统在海洋生物监测应用中的巨大潜力。此外，笔者团队还搭建了一套四维凝视成像探测系统能实现高光谱分辨率（3 nm）、高空间分辨率、高深度精度（27.5 μm）的精准探测。
高光谱图谱仪 沙姆激光雷达系统 水母 棕囊藻 四维探测 hyperspectral imager Scheimpflug lidar system jelly fish phaeocystis 4D detection 红外与激光工程
2021, 50(6): 20211033
Author Affiliations
Abstract
1 Key Laboratory of Advanced Transducers and Intelligent Control System, Ministry of Education and Shanxi Province, College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China
2 Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, National Engineering Research Center for Optical Instruments, Zhejiang University, Hangzhou 310058, China
A novel way to design arbitrarily shaped retro-reflectors by optics surface transformation is proposed. The entire design process consists of filling an optic-null medium between the input and output surfaces of the retro-reflector, on which the points have 180 deg reverse corresponding relations. The retro-reflector can be designed to be very thin (a planar structure) with high efficiency. The effective working angles of our retro-reflector are very large (from ?80 deg to +80 deg), which can, in principle, be further extended. Layered metal plates and zero refractive index materials are designed to realize the proposed retro-reflector for a TM polarized beam.
retro-reflector optics surface transformation Chinese Optics Letters
2020, 18(10): 102201
Author Affiliations
Abstract
1 Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, France
2 Zhejiang University, Centre for Optical and Electromagnetic Research, State Key Laboratory for Modern Optical Instrumentation, Hangzhou, China
Dispersion engineering of optical waveguides is among the most important steps in enabling the realization of Kerr optical frequency combs. A recurring problem is the limited bandwidth in which the nonlinear phase matching condition is satisfied, due to the dispersion of the waveguide. This limitation is particularly stringent in high-index-contrast technologies such as silicon-on-insulator. We propose a general approach to stretch the bandwidth of Kerr frequency combs based on subwavelength engineering of single-mode waveguides with self-adaptive boundaries. The wideband flattened dispersion operation comes from the particular property of the waveguide optical mode that automatically self-adapts its spatial profile at different wavelengths to slightly different effective spatial spans determined by its effective index values. This flattened dispersion relies on the squeezing of small normal-dispersion regions between two anomalous spectral zones, which enables it to achieve two Cherenkov radiation points and substantially broaden the comb, achieving a bandwidth between 2.2 and 3.4 μm wavelength. This strategy opens up a design space for trimming the spectra of Kerr frequency combs using high-index-contrast platforms and can provide benefits to various nonlinear applications in which the manipulation of energy spacing and phase matching are pivotal.
nonlinear optics effective boundary subwavelength grating silicon frequency comb Advanced Photonics
2020, 2(4): 046001
1 国家光学仪器工程研究中心 浙江大学光及电磁波研究中心, 浙江 杭州 310058
2 浙江大学 宁波研究院, 浙江 宁波 315100
海洋是地球生态环境的重要一环, 但人类对海洋资源的勘探和开采容易对其造成严重破坏, 如油气开采过程造成的大面积溢油、污染和赤潮爆发等。高光谱成像技术可以同时获取图像信息与高分辨光谱信息, 在海洋原位探测上具有重大应用。文中综述了小型高光谱图谱仪与激光雷达及其在海洋应用上的部分近期工作。小型高光谱图谱仪结合荧光技术, 实现了溢油种类的分类和油膜厚度的估计。多模式高光谱海洋原位探测系统可以工作于普通反射或透射成像、望远成像、显微成像三种模式, 实现了海洋不同藻类及鱼类传染病载体孢囊的高光谱探测。高光谱技术结合激光雷达技术在溢油、赤潮等海洋污染物监测方面具有很大潜力。非弹性高光谱沙姆激光雷达系统通过油品的荧光光谱实现了海洋溢油油品的遥测鉴别。形貌沙姆激光雷达系统基于二维沙姆成像原理, 通过空气-水界面折射矫正, 成功的对人体、贝壳、珊瑚等进行了三维形貌重构, 近处恢复精度可达毫米级, 表面纹路清晰可见, 为海洋监测应用提供了新的技术支持。
高光谱图谱仪 沙姆激光雷达系统 沙姆成像原理 溢油 赤潮 海洋原位探测 三维形貌 hyperspectral imager Scheimpflug lidar system Scheimpflug imaging principle oil spill red tide marine in-situ detection 3D shape 红外与激光工程
2020, 49(2): 0203001
Author Affiliations
Abstract
1 Centre for Optical and Electromagnetic Research, National Engineering Research Center for Optical Instruments, Zhejiang University, Hangzhou 310058, China
2 Ningbo Research Institute, Zhejiang University, Ningbo 315100, China
In this paper, recent advances in underwater wireless optical communication (UWOC) are reviewed for both LED- and LD-based systems, mainly from a perspective of advanced modulation formats. Volterra series-based nonlinear equalizers, which can effectively counteract the nonlinear impairments induced by the UWOC system components, are discussed and experimentally demonstrated. Both the effectiveness and robustness of the proposed Volterra nonlinear equalizer in UWOC systems under different water turbidities are validated. To further approach the Shannon capacity limit of the UWOC system, the probabilistic constellation shaping technique is introduced, which can overcome the inherent gap between a conventional regular quadrature amplitude modulation (QAM) format and the Shannon capacity of the channel. The experimental results have shown a significant system capacity improvement compared to the cases using a regular QAM.
060.2605 Free-space optical communication 060.4080 Modulation 140.7300 Visible lasers 010.4450 Oceanic optics Chinese Optics Letters
2019, 17(10): 100012
Author Affiliations
Abstract
1 State Key Laboratory of Modern Optical Instrumentations, Centre for Optical and Electromagnetic Research, Zhejiang University, Hangzhou 310058, P. R. China
2 School of Electrical Engineering, Royal Institute of Technology, Stockholm SE-100 44, Sweden
Two-photon luminescence with near-infrared (NIR) excitation of upconversion nanoparticles (NPs) is of great importance in biological imaging due to deep penetration in high-scattering tissues, low auto-luminescence and good sectioning ability. Unfortunately, common two-photon luminescence is in visible band with an extremely high exciation power density, which limits its application. Here, we synthesized NaYF4:Yb/Tm@NaYF4 upconversion NPs with strong twophoton NIR emission and a low excitation power density. Furthermore, NaYF4:Yb/Tm@NaYF4@SiO2@OTMS@F127 NPs with high chemical stability were obtained by a modified multilayer coating method which was applied to upconversion NPs for the first time. In addition, it is shown that the as-prepared hydrophillic upconversion NPs have great biocompatibility and kept stable for 6 hours during in vivo whole-body imaging. The vessels with two-photon luminescence were clear even under an excitation power density as low as 25mW/cm2. Vivid visualizations of capillaries and vessels in a mouse brain were also obtained with low background and high contrast. Because of cheaper instruments and safer power density, the NIR two-photon luminescence of NaYF4:Yb/Tm@NaYF4 upconversion NPs could promote wider application of two-photon technology. The modified multilayer coating method could be widely used for upconversion NPs to increase the stable time of the in vivo circulation. Our work possesses a great potential for deep imaging and imaging-guided treatment in the future.
Ultra-stable upconversion nanoparticles two-photon luminescence in vivo brain angiography low excitation power density Journal of Innovative Optical Health Sciences
2019, 12(3): 1950013
Author Affiliations
Abstract
Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310058, China
All-optical two-channel format conversion is proposed and experimentally demonstrated from a 40 Gbit/s polarization multiplexing (Pol-MUX) non-return-to-zero quadrature phase-shift keying (QPSK) signal to Pol-MUX binary phase-shift keying (BPSK) signals by using phase-doubled four-wave mixing effects with two polarization-angled pumps in a silicon waveguide. The eye diagrams and constellation diagrams of the original QPSK sequences and the converted BPSK sequences of each channel are clearly observed on the two polarization states. Moreover, the bit error rates (BERs) of the two converted idlers are measured. The power penalties of all these converted BPSK sequences on both X and Y polarization states are less than 3.4 dB at a BER of 3.8 × 10?3.(20130101110089); Natural Science Foundation of Zhejiang Province (LY14F050006).
Phase modulation Phase modulation Nonlinear optical signal processing Nonlinear optical signal processing Nonlinear optics Nonlinear optics four-wave mixing four-wave mixing Nonlinear optics Nonlinear optics integrated optics integrated optics Photonics Research
2016, 4(6): 06000245
浙江大学现代光学仪器国家重点实验室, 浙江省传感重点实验室, 光及电磁波研究中心, 浙江 杭州 310058
在钢板的生产和使用过程中，钢板厚度的测量极其重要。传统的激光三角法不适合测量粗糙表面物体和多散射介质的厚度。基于硅酸铋光折变晶体搭建了一套自适应的双波混合干涉仪系统，使用该系统精确测量了铝块的厚度。由于光折变效应形成的全息光栅使信号光和参考光发生衍射，解调出超声振动信号。动态全息光栅的形成，能自动滤除环境引起的低频扰动。该系统在厚度测量、粗糙面超声振动测量中具有灵敏度高、调节方便、非接触、价格相对便宜等特点，将来与激光超声技术相结合在内部缺陷检测上有非常广阔的前景。
测量 双波混合 全息光栅 金属板 超声
1 华南师范大学, 光及电磁波研究中心, 广东 广州 510006
2 浙江中控太阳能技术有限公司, 浙江 杭州 310053
先进的光学纳米探针对于生物组织的光学成像、疾病的诊断和治疗具有巨大的促进作用, 尤其是对于生物体分子水平活动的动态信息的深入了解。新型的光学探针如纳米金棒、上转换纳米颗粒和氧化石墨烯等, 能克服传统探针的一些不足, 具有较高的对比度、稳定性和生物兼容性, 而且还拥有深层组织成像和实时动态成像的能力。本文对这些纳米光学探针的光学性质和优点进行了简要的介绍, 并通过综述作者及其他研究者在过去几年的研究成果, 总结这些先进的纳米探针在生物成像和医学诊断、治疗方面的应用, 并展望其应用前景。
光学探针 纳米颗粒 生物光学成像 optical probes nanoparticles bioimaging
