非线性光学超构表面：基础与应用

光学超构表面是一种由亚波长尺度的超构单元在面内排布而构成的准二维人工结构材料。研究人员可以通过选择超构单元的材料组成、几何形状对光的振幅、偏振、相位和频率等光场自由度进行灵活调控。聚焦于超构表面在非线性光场调控领域的原理与应用。首先,概述了非线性晶体到非线性超构表面的发展历程。然后,讨论了对称性和几何相位在非线性光学超构表面中的重要作用。最后,介绍了非线性光学超构表面在波前调控、量子信息处理和太赫兹波的产生与调控等领域中的应用。     

倍频及参量过程中的相位匹配角折返现象

许多非线性光学晶体在倍频及参量过程中的相位匹配角折返现象目前已由中国科学院物理研究所通过计算得到证实,并由基于经典光学的理论成功地解释了该现象的普遍性,得出倍频及参量过程中的相位匹配角折返现象广泛存在于一类和二类匹配的单轴及双轴晶体中的重要结论. 非线性光学晶体的相位匹配角折返现象是一种十分有趣且具有应用前景的新现象.倍频过程中的相位匹配角折返现象是指当晶体处于某一角度时,存在两个(或两个以上)不同频率的相干光同时倍频相位匹配.参量过程中的相位匹配角折返现象是指当泵浦光频率及晶体角度处在某一范围时,存在两…     

铌酸锂薄膜上的非线性频率变换

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。     

布洛姆伯根与非线性光学效应

1961年第一台激光器发明不久,弗兰克(P.A.Franken)等人利用红宝石激光器在光波段观察到二次谐波的产生,这是最早发现的二阶非线性光学效应。1962年,布洛姆伯根(Nicolaas Bloembergen,1920~)等提出了实现高效非线性频率变换的准相位匹配(QPM)理论,1965年出版专著《非线性光学》。布洛姆伯根对非线性光学频率变换进行了开创性的理论工作,在科学研究和实际应用中具有重要意义。在布洛姆伯根奠定的理论基础上,出现了研究非线性光学效应的热潮,人们陆续发现和探讨了各种非线性光学效应,如受激拉曼散射、受激布里渊散射和光学参量振荡等。此后…     

分形超晶格结构晶体中的多波长频率转换

非线性频率转换是非线性光学中的重点研究内容之一,本文将Gosper分形与Z分形两种超晶格结构引入非线性光子晶体中,理论分析了两种超晶格结构经过准相位匹配进行非线性频率转换的谐波特点。Gosper分形超晶格的倒空间结构整体旋转60°后,依然能够和原图形重合;在准相位匹配的条件下,能够在六个不同方向实现相同的倍频波长输出;在级联三倍频中,实现了波长为711.3 nm、554.7 nm、491 nm的三倍频输出,并理论计算了其偏离角度。在二维Z分形的傅里叶空间中,充分利用了高阶横向倒格矢,能够实现基波波长范围为1.402μm～1.430μm的二次谐波频率转换,其中波长间距最小仅有1 nm。最后,为三维Z分形超晶格结构晶体的制备提供了数据支持。     

中远红外非线性光学晶体研究进展

3—5μm和8—12μm波段中远红外激光,在国防和民用领域均具有广泛的应用,作为全固态激光频率转换系统的核心部件,非线性光学晶体需要不断地优化和发展.本文从红外非线性光学晶体材料组成角度出发,总结了几种具有重大应用前景的磷族化合物(ZnGeP_2,CdSiP_2)、硫属化合物(CdSe, GaSe, LiInS_2系列,BaGa_4S_7系列)以及准位相匹配晶体(OP-GaAs, OP-GaP)等中远红外波段非线性光学晶体的研究进展.     

非线性光学相位共轭及其在激光工程中的应用

非线性光学相位共轭是现代光学一个有生命力的分支，文章简单介绍了它的原理和产生相位共轭波的几种基本途径，重点介绍了它在激光工程中的可能应用与进展，并指出有待研究解决的问题。     

光学参变啁啾脉冲放大相位失配啁啾脉冲频谱整形新方法

相位匹配是实现高效光学参变啁啾脉冲放大(OPCPA)能量转换的关键之一,通过对几种常用非线性晶体的光学参变啁啾脉冲放大过程进行数值模拟研究,结果表明一定程度的相位失配不但能增加光学参变啁啾脉冲放大增益带宽,而且会使啁啾脉冲光谱强度分布中间凹陷。提出利用光学参变啁啾脉冲放大相位失配放大作为啁啾脉冲频谱整形的新方法,通过理论分析和模拟计算,找到了光学参变啁啾脉冲放大相位失配啁啾脉冲频谱整形效果的控制量;并对几种常用非线性晶体在简并、近简并、非简并等条件下的光学参变啁啾脉冲放大相位失配放大特性进行了比较。     

获得蛋白质激光脉冲升温光源方法的比较研究

触发蛋白质开折叠可以使用激光脉冲升温溶剂产生温跳的方法。红外光谱研究中常用的激光波长为1.9μm,可以通过钬激光器、半导体激光器和光参量振荡(OPO)等非线性光学的方法来实现频率转换。在拥有Nd∶YAG激光光源的情况下,对由LiNbO3晶体差频、临界相位匹配(CPM)的KTP OPO和高压氢气受激拉曼散射所获得的1.9μm激光输出的实验方法进行了比较。结果表明,受激拉曼散射是获得频率转换最有效而便捷的方法。     

利用各向同性半导体晶体差频产生可调谐THz辐射的理论研究

理论研究了利用剩余射线带色散补偿相位匹配原理，在Ⅲ-Ⅴ族和Ⅱ-Ⅳ族光学各向同性的半导体非线性晶体中差频产生可调谐THz波的可行性问题.根据这些半导体材料的色散特性，并以近简并点双共振KTP-OPO的可调谐相干双波长输出作为差频抽运源，对它们的相位匹配能力、差频增益特性、品质因数以及差频过程中的相干长度进行了理论分析和计算，确定了ZnTe晶体是在共线相位匹配情况下较为理想的THz波差频晶体，而InP晶体则更适合用于非共线相位匹配情况. 关键词： 非线性光学 THz辐射 差频 各向同性半导体晶体     

Electro-Optic Polymer Integrated Optic Devices and Future Applications

Recent developments in electro-optic polymer materials and devices have led to new opportunities for integrated optic devices in numerous applications. The results of numerous tests have indicated that polymer materials have many properties that are suitable for use in high-speed communications systems, various sensor systems, and space applications. These results, coupled with recent advances in device and material technology, will allow very large bandwidth modulators and switches with low drive voltages, improved loss, long-term stability, and integration with other microelectronic devices such as MEMS. Low drive voltage devices are very important for space applications where power consumption scales as the square of the modulator half-wave voltage. In addition, we have demonstrated novel dual polymer modulators for mixing RF signals to produce sum and difference frequency modulation on an optical beam. This novel approach allows the suppression of the modulation at the two input RF signals, and only the mixing signals remain superposed on the optical beam. The dual modulator can be used for various encoding/decoding and frequency conversion schemes that are frequently used for both terrestrial and space communications. Another application of polymer integrated optics is in the field of optical sensing for high-frequency (GHz) electric fields.     

Electro-Optic Polymer Integrated Optic Devices and Future Applications

Recent developments in electro-optic polymer materials and devices have led to new opportunities for integrated optic devices in numerous applications. The results of numerous tests have indicated that polymer materials have many properties that are suitable for use in high-speed communications systems, various sensor systems, and space applications. These results, coupled with recent advances in device and material technology, will allow very large bandwidth modulators and switches with low drive voltages, improved loss, long-term stability, and integration with other microelectronic devices such as MEMS. Low drive voltage devices are very important for space applications where power consumption scales as the square of the modulator half-wave voltage. In addition, we have demonstrated novel dual polymer modulators for mixing RF signals to produce sum and difference frequency modulation on an optical beam. This novel approach allows the suppression of the modulation at the two input RF signals, and only the mixing signals remain superposed on the optical beam. The dual modulator can be used for various encoding/decoding and frequency conversion schemes that are frequently used for both terrestrial and space communications. Another application of polymer integrated optics is in the field of optical sensing for high-frequency (GHz) electric fields.     

High‐resolution spectral characterization of two photon states via classical measurements

Quantum optics plays a central role in the study of fundamental concepts in quantum mechanics, and in the development of new technological applications. Typical experiments employ sources of photon pairs generated by parametric processes such as spontaneous parametric down‐conversion and spontaneous four‐wave‐mixing. The standard characterization of these sources relies on detecting the pairs themselves and thus requires single photon detectors, which limit both measurement speed and accuracy. Here it is shown that the two‐photon quantum state that would be generated by parametric fluorescence can be characterised with unprecedented spectral resolution by performing a classical experiment. This streamlined technique gives access to hitherto unexplored features of two‐photon states and has the potential to speed up design and testing of massively parallel integrated nonlinear sources by providing a fast and reliable quality control procedure. Additionally, it allows for the engineering of quantum light states at a significantly higher level of spectral detail, powering future quantum optical applications based on time‐energy photon correlations.     

The geometric phase in nonlinear frequency conversion

The geometric phase of light has been demonstrated in various platforms of the linear optical regime, raising interest both for fundamental science as well as applications, such as flat optical elements. Recently, the concept of geometric phases has been extended to nonlinear optics, following advances in engineering both bulk nonlinear photonic crystals and nonlinear metasurfaces. These new technologies offer a great promise of applications for nonlinear manipulation of light. In this review, we cover the recent theoretical and experimental advances in the field of geometric phases accompanying nonlinear frequency conversion. We first consider the case of bulk nonlinear photonic crystals, in which the interaction between propagating waves is quasi-phase-matched, with an engineerable geometric phase accumulated by the light. Nonlinear photonic crystals can offer efficient and robust frequency conversion in both the linearized and fully-nonlinear regimes of interaction, and allow for several applications including adiabatic mode conversion, electromagnetic nonreciprocity and novel topological effects for light. We then cover the rapidly-growing field of nonlinear Pancharatnam-Berry metasurfaces, which allow the simultaneous nonlinear generation and shaping of light by using ultrathin optical elements with subwavelength phase and amplitude resolution. We discuss the macroscopic selection rules that depend on the rotational symmetry of the constituent meta-atoms, the order of the harmonic generations, and the change in circular polarization. Continuous geometric phase gradients allow the steering of light beams and shaping of their spatial modes. More complex designs perform nonlinear imaging and multiplex nonlinear holograms, where the functionality is varied according to the generated harmonic order and polarization. Recent advancements in the fabrication of three dimensional nonlinear photonic crystals, as well as the pursuit of quantum light sources based on nonlinear metasurfaces, offer exciting new possibilities for novel nonlinear optical applications based on geometric phases.     

Graphene integrated photodetectors and opto-electronic devices — a review

Graphene and other two-dimensional materials have recently emerged as promising candidates for next-generation,high-performance photonics. In this paper, the progress of research into photodetectors and other electro-optical devices based on graphene integrated silicon photonics is briefly reviewed. We discuss the performance metrics, photo-response mechanisms, and experimental results of the latest graphene photodetectors integrated with silicon photonics. We also lay out the unavoidable performance trade-offs in meeting the requirements of various applications. In addition, we describe other opto-electronic devices based on this idea. Integrating two-dimensional materials with a silicon platform provides new opportunities in advanced integrated photonics.     

Ultrafast optical pulse shaping: A tutorial review

This paper presents a tutorial on the field of femtosecond pulse shaping, a technology that enables generation of nearly arbitrary, user defined, ultrafast optical waveforms, with control of phase, amplitude, and polarization. The emphasis is on Fourier transform pulse shaping, the most widely applied technique. Selected pulse shaping applications are described, with specific discussion of coherent control of quantum and nonlinear processes and of lightwave communications. Two new areas of pulse shaping research, namely, hyperfine spectral resolution pulse shaping and pulse shaping applications in ultrabroadband RF photonics, are discussed and illustrated with examples taken from the author's laboratory.     

基于近场激发与增强的新型多层纳米薄膜结构在非线性光学器件上的应用与发展前景

传统光学引入了远场衍射的尺度极限。自从提出了近场光学技术以来 ,由于近场扫描光学显微镜 (NSOM)系统的复杂性而使得近扬的引入和利用变得困难。具有多层纳米薄膜结构的超分辨近场结构 (Super RENS)的提出改变了这种局面 ,并在诸如超高密度光学数据存储、近场光刻技术、纳米光子学晶体管等领域获得了重要的应用。围绕Su per RENS技术 ,通过综述它的基本原理、物理机制以及各项应用 ,指出了基于近场激发与增强原理的新型多层纳米薄膜结构在未来非线性光学器件上的应用与发展前景     

Efficient Integrated Graphene Photonics in the Visible and Near‐IR

Graphene photonics has emerged as a promising platform for providing desirable optical functionality. However, graphene's monolayer‐scale thickness fundamentally restricts the available light matter interaction, posing a critical design challenge for integrated devices, particularly in wavelength regimes where graphene plasmonics is untenable. While several plasmonic designs have been proposed to enhance graphene light interaction in these regimes, they suffer from substantial insertion loss due to metal absorption. Here we report a non‐resonant metamaterial‐based waveguide platform to overcome the design bottleneck associated with graphene device. Such metamaterial structure enables low insertion loss even though metal is being utilized. By examining waveguide dispersion characteristics via closed‐form analysis, it is demonstrated that the metamaterial approach can provide optimized optical field that overlaps with the graphene monolayer. This enables graphene‐based integrated components with superior optical performance. Specifically, the metamaterial‐assisted graphene modulator can provide 5‐fold improvement in extinction ratio compared to Si nanowire, while reducing insertion loss by one order magnitude compared to plasmonic structures. Such a waveguide configuration thus allows one to maximize the optical potential that graphene holds in the telecom and visible regimes.     

Semiconductor optical fibres: progress and opportunities

This paper reviews recent progress in the nascent field of semiconductor optical fibres, from the fundamentals through to device demonstration. The incorporation of semiconductor materials into both the step‐index and microstructured fibre geometries provides a route to introducing new optoelectronic functionality into existing glass fibre technologies. Herein, the various fabrication methods that have been developed as of to date are described, and their compatibility with the different semiconductor materials and fibre designs discussed. Results will be presented on the optical transmission properties of several fibre types, with particular attention being paid to the observation of nonlinear propagation in silicon core fibres. Finally, some speculation regarding the future prospects and applications of this new class of fibre will be provided.     

细菌视紫红质膜非线性吸收特性及其光子学应用

对细菌视紫红质膜在两束非同频光照射下的非线性吸收特性进行了详细的理论分析,并讨论了细菌视紫红质膜非线性吸收特性有光子学方面的一些新应用。