Atom optics with hollow optical systems

Recent theoretical as well as experimental progress in atom optics using optical means—in particular, hollow optical systems such as pyramidal hollow mirror, conical hollow mirror, and hollow-core optical fiber—are presented. These hollow optical systems provide the dark hollow region where atoms can be manipulated in a way so as to minimize the external perturbations due to the optical fields once the atoms are cooled and trapped. Therefore, such systems provide very simple and reliable ways of preparing precooled atoms for further elaborate atom optics experiments and also for introducing them efficiently into low-dimensional space, such as the 2D atomic channel or the 1D atomic wire.     

Polymer optical waveguide based on integrated optics

The fabrication and characterization of refractive index profiles of multimode mode polymer optical waveguides is reported. Effect of annealing temperature on guided losses of polymer (polystyrene) thin film optical waveguide is also presented. Efficient coupling over a 110 nm spectral bandwidth was experimentally demonstrated with a prism-coupler designed to match the dispersion of a particular waveguide.     

Gradient-index planar optics for optical interconnections

Use of a gradient-index (GRIN) substrate is proposed as a novel signal-propagation medium for planar optics. The GRIN substrate provides planar optics designers not only a three-dimensional light propagation space but also smart optical diffraction-limited imaging. Experimental results on the imaging of an input signal to multiple destinations by the GRIN planar optics are presented.     

Transformation optics and infrared metamaterials for optical devices

The coordinate transformation approach is applied for the design of an optical mode adaptor between two different width waveguides in the near IR telecom optical domain. The control of the mode profile in the adaptor is achieved by considering a composite waveguide consisting of a thin metamaterial (MM) layer intercalated between 2???m thick SU8 photoresist slab and a glass substrate. We demonstrate that intercalated metafilm enables the realization of a space coordinate transformation and allows a precise control of the light propagation in the composite waveguide. Numerical simulations and experimental realizations of the metamaterial layer are performed in order to validate the device concept and realization feasibility.     

光学仪器胶粘剂应用现状及进展

本文是在对国内光学零件加工及光学仪器产品胶粘剂的应用现状与研究动态的调研基础上，结合作者的工作，综合介绍了光学零件加工过程中工艺用粘接材料与工艺材料用树脂结合剂；光学零件、光学分划元件、光学偏振元件、光学塑料元件等的胶合用光学胶；光学仪器产品结构用结构胶及非结构胶；光学仪器产品及部件用密封胶等的应用现状及其进展概况     

Dispersion compensation by microstructured optical devices in ultrafast optics

Dispersion compensation is a ubiquitous problem for the generation and application of ultrashort optical pulses. Early approaches to compensate for the spectral group-delay dependence in materials used prism and grating sequences for this purpose, but are limited in bandwidth. Microstructuring dielectric optical materials on the scale of the optical wavelength have developed as an alternative for inducing a desired spectral group-delay dependence. With this approach a nearly arbitrary dependence of group delay vs. wavelength can be compensated for. We will discuss different approaches to microstructured dispersion compensation, namely chirped Bragg gratings, different generations of chirped mirrors, quasi-phase-matching gratings, and arrayed-waveguide gratings. We will outline common limitations and discuss ideas to expand further the utility of these approaches. PACS 42.65 Re; 42.79 Wc; 42.81 Wg     

基于自适应光学补偿的自由空间光通信系统性能研究

自由空间光通信在未来全球通信网中具有潜在的应用价值,然而自由空间光通信的性能易受大气湍流影响,而自适应光学能够解决大气湍流问题.在gamma-gamma分布大气湍流中,用自适应光学技术对自由空间光通信系统进行补偿,进行通信系统误码率的分析,给出了上行链路和下行链路的模拟结果.结果表明:自适应光学误差补偿技术能够很好地提高自由空间光通信的性能,并且低阶自适应光学补偿就能达到很好的校正效果.     

二元光学在光学观测轰炸瞄准中的应用研究

光学观测瞄准是大中型轰炸机主要的对地攻击瞄准方式,其光学系统一般采用望远式光学系统,这就要求光学系统能满足可见光和近红外光两个光谱波段。根据国内大中型轰炸机光学观测瞄准系统的主要缺陷,结合光学观测瞄准的实际,探讨了基于二元光学的光学观测系统的组成结构和瞄准原理,分析了可见光波段混合目镜的光学性能、谐衍射物镜的衍射效率以及近红外光波段光学系统的像质,推导了横偏棱镜调平误差引起的瞄准误差的数学表达式,并对设计的合理性进行了验证。     

Adaptive optics optical coherence tomography for retina imaging

When optical coherence tomography (OCT) is used for human retina imaging, its transverse resolution is limited by the aberrations of human eyes. To overcome this disadvantage, a high resolution imaging system for living human retina, which consists of a time domain OCT system and a 37-elements adaptive optics (AO) system, has been developed. The AO closed loop rate is 20 frames per second, and the OCT has a 6.7-μm axial resolution. In this paper, this system is introduced and the high resolution imaging results for retina are presented.     

Line width analysis of a tunable optical filter based on free-space optics

The line width of a tunable optical filter based on free-space optics was analyzed. The relationship between the line width and the Gaussian beam waist was theoretically derived and experimentally verified. The experimental results meet the theoretical analysis well, which is beneficial for the design of a tunable optical filter based on free-space optics.     

Realization of an optical interferometer based on holographic optics for real-time testing of phase objects

The paper describes a simple and cost effective method for the realization of an optical interferometer based on holographic optics, which use minimal bulk optical components. The optical arrangement in the proposed method involves a very simple alignment procedure and inexpensive holographic recording material is used in the formation of holographic optical elements. The proposed interferometer set-up is quite suitable for performing optical test studies on phase (transparent) objects in real-time. Recording schemes for the formation of holographic optical elements and the related technique for the realization of the interferometer set-up along with the experimental results have been presented.     

基于衍射光学元件的红外弱目标探测系统设计

根据非制冷焦平面阵列（FPA）探测器性能参数以及所需探测红外弱目标的大小与探测距离,计算并设置了系统参数,设计并研制了与之相匹配的长波红外光学系统,实现了对红外弱目标的探测。该红外光学系统基于6°×6°视场角,采用像方远心光路来实现。分析与计算结果表明,采用衍射非球面设计的由两片Ge镜片组成的红外弱目标探测光学系统具有重量轻、系统能量传输效率高和像质优良的优势。与三片球面Ge-AMTIR1-Ge红外光学系统相比,系统质量轻25%,能量传输效率高7%;与常规非球面Ge-Ge透镜系统相比,像质改善50%。比较结果显示,可见衍射非球面光学元件在红外弱目标探测系统中具有较好的应用前景。     

空间相机光学窗口热光学性能的仿真分析

 空间相机光学窗口与周围环境进行热交换,导致窗口的温度发生不均匀变化,包括整体温度水平的变化以及产生径向温差、周向温差和轴向温差。这些温度梯度将影响相机的光学系统质量。针对某相机光学窗口温度分布不均匀的特点,提出利用非顺序光路建立复杂光瞳的方法对光学窗口进行分区,在各子区域上建立温度的径向分布特征,然后将各子区域的变化再统一到整个元件中,进而评判对整个系统的影响。结果表明,新方法合理可行,温度周向不均匀分布会降低光学系统质量,并且不能完全通过离焦来补偿。     

Bounds to the difference between the predictions of stochastic and quantum optics in the optical test of bell inequalities

We summarize the main ideas and problems of stochastic optics, a theory recently proposed by T.W. Marshall and E. Santos, which explains in a local realist way some experiments thought to be non-local, generalizing previous results in order to make it possible to calculate the difference between the quantum mechanical and the stochastic optical predictions for the optical test of Bell's inequalities.     

A module design of rearrangeable nonblocking double omega optical network using binary optics elements

Omega network plays an important role in all optical communication and optical interconnection networks. In this paper, a novel technology, which binary optics element (micro-blazed grating array) can realize perfect shuffle transform including inverse perfect shuffle and left perfect shuffle, is proposed. Moreover, by a cascade of inverse perfect shuffle and left perfect shuffle, a multistage rearrangeable nonblocking omega network can be constructed. Simultaneously, the bipartition graph algorithm (BGA) is adopted to ascertain the state of node switch in each node stage (straight or crossover connection). At last, a module of the rearrangeable nonblocking omega network which is integrated with polarizing beam-splitter, half-wave plate, micro-blazed grating array, is presented. It can accomplish the functions of 8-channel signal beams’ sorting and switching without routing conflict and blocking, and has advantages of being compact in structure, easy to integrate, efficient in performance etc. Finally, both the theoretical analysis and the experimental result show that this module proposed here may be helpful in free-space optical interconnection network and optical information processing.     

Geometric optics approach to optical fibre excitation by partially coherent sources

A general partially coherent source field on the end of an optical fibre has been represented by a characteristic angular spectrum of independent plane waves. The launching of both trapped and tunnelling (leaky) power is investigated for both step and graded-index fibres by considering the effect of one component of the angular spectrum, using geometric optics acceptance theory. The effect of the degree of coherence on the pulse response of the fibres is briefly discussed.     

Spectral domain optical coherence tomography imaging with an integrated optics spectrometer

We designed and fabricated an arrayed-waveguide grating (AWG) in silicon oxynitride as a spectrometer for spectral domain optical coherence tomography (SD-OCT). The AWG has a footprint of only 3.0 cm × 2.5 cm, operates at a center wavelength of 1300 nm, and has 78 nm free spectral range. OCT measurements are performed that demonstrate imaging up to a maximum depth of 1 mm with an axial resolution of 19 μm, both in agreement with the AWG design parameters. Using the AWG spectrometer combined with a fiber-based SD-OCT system, we demonstrate cross-sectional OCT imaging of a multilayered scattering phantom.     

New silicon-based fibre assemblies for applications in integrated optics and optical MEMS

Nearly closed rhombus-shaped channels in micromachined silicon with very high accuracy for fibre array assemblies are presented. The fabrication and the assembly of fibres are described. The achieved accuracy is comparable with conventional V-groove assemblies. Additionally, rhombus-shaped channels allow new applications such as monitor pigtails with integrated photodiodes or buried fibre supplies in optical MEMS. Received: 22 May 2001 / Revised version: 7 September 2001 / Published online: 30 October 2001     

Fiber Fourier optics

The Fourier transform of a coherent optical image can be evaluated physically by use of a single lens plus free-space propagation, thereby providing the basis for the field of Fourier optics. I point out that one can similarly evaluate the discrete Fourier transform of a sampled or pixelated optical array physically by passing the discrete array amplitudes through a network of single-mode fibers or optical waveguides. A passive optical network that evaluates the fast Fourier transform of a coherent array can be fabricated by use of (N/2)log(2)[N] optical 3-dB couplers plus small added phase shifts. Implementing such networks in fiber or integrated optical form could provide the basis for a possible technology of fiber Fourier optics.     

Origin of giant optical nonlinearity in charge-transfer-mott insulators: a new paradigm for nonlinear optics

Neither pure Mott insulators nor pure charge-transfer insulators have ever been considered as a possible candidate for nonlinear optical (NLO) materials since individually neither the strong correlation (U) nor the large charge transfer (Delta) is favorable to the NLO response. However, in their composites, charge-transfer-Mott insulators, jointly Delta and U can enhance the hyperpolarizability (gamma) by guiding the ground states into the antiferromagnetic phase and the excited states into the charge-transfer phase. These Delta and U that maximize gamma form a unique golden Delta-U line, on which the recently observed giant nonlinear optical effect is just a single point, whose physical origin is that the system is driven into a phase-separated region for the ground and excited states. This novel mechanism may suggest a conceptually new paradigm to explore an even larger optical nonlinearity.