Tunable laser optics: Applications to optics and quantum optics

Optics originally developed for tunable organic dye lasers have found applications in other areas of optics, laser optics, and quantum optics. Here, the salient aspects of the physics related to the cavity linewidth equation and the effects of intracavity beam expansion and intracavity dispersion on this equation are reviewed. Additionally, the generalized multiple-prism dispersion equation is applied to direct-vision prisms, also known as Amici prisms, to calculate dispersion configurations of practical interest. Then, the higher derivatives of the multiple-prism dispersion equation applicable to laser pulse compression are considered. From this perspective, a new compact and generalized equation for higher-order phase derivatives is introduced for the first time. Furthermore, it is shown how the N-slit interferometric equation, derived from quantum principles using Dirac's notation, gives rise to generalized versions of the diffraction grating equation and the law of refraction. The nexus between the N-slit interferometric equation and the cavity linewidth equation is also illustrated. Finally, various optical and quantum optical applications that have benefited from these developments are highlighted.     

基于超构表面的非线性光学与量子光学

近年来,超构表面在经典光场调控领域受到了广泛的关注,获得了优异的成果。同时,超构表面在非线性光学和量子光学方面的应用也引起了人们越来越多的兴趣。文中分别介绍了非线性超构表面和量子超构表面的基本原理和应用,总结了近几年的相关报道,包括谐波产生和增强,谐波产生和对称性的关系,非线性相位调控和全息成像,以及基于超构表面的纠缠光子对产生,测量和调控。最后,对超构表面在这两个领域的进一步应用和前景进行了展望。     

集成光学

一、概述 70年代初，低损耗光纤的出现开拓了光通讯实用化的前景，对于可靠的通讯系统，紧凑的光学器件以及对它们的集成是非常需要的。显然，集成光学的目的就是要使光学器件系统小型化、集成化。至于集成到什么样的规模，人们的想像肯定会受到微电子学成功的鼓舞。     

Digital optics

The authors discuss digital optics, a technology for processing, transport, and storage of optical digital information. Digital optics offers both the high temporal bandwidth of fiber communications and the high connectivity and information density of optical imaging. The energy dissipation per bit of communicated information, as well as the chip area dedicated to interconnections, can be significantly lower in optics than in high-speed electronics. This motivates the introduction of parallel optical interconnections through free space in communication-intensive areas of digital information processing such as switching in telecommunications and within multiprocessors. Digital optical circuits can be constructed by cascading two-dimensional planar arrays of optical logic gates interconnected in free space. The state of the art and the trends in digital optical information processing systems for optical logic, optoelectronic interfaces, and optical free-space interconnection systems are reviewed     

Nonlinear optics

Recent advances in the field of nonlinear optical phenomena are reviewed with particular empphasis placed on such topics as parametric oscillation self-focusing and trapping of laser beams, and stimulated Raman, Rayleigh, and Brillouin scattering. The optical frequency radiation is treated classically in terms of the amplitudes and phases of the electromagnetic fields. The interactions of light waves in a mterial are then formulated in terms of Maxwell's equations and the electric dipole approximation. In this method, non-linear susceptibility tensors are introdueed which relate the induced dipole moment to a power series expansion in field strengths. The tensor nature and the frequency dependence of the nonlinearity coefficients are considered. The various experimental, observations are described and interpreted in terms of this formalism.     

Long-wave optics

The basis of the near-complete analytical methodology that now exists for the design of long-wave optical systems is set out. The Gaussian beam-mode treatment of free-space propagation is extended to cover the transformations produced by conic-section reflectors or lenses, and both the propagation steps and the lens transformations are incorporated into a matrix formulation readily applicable to networks of such reflectors or lenses. In the process the theorems of Fourier optics are demonstrated and the vectorial properties of the beam-fields are kept explicit. It is shown how recent formulations of partial coherence have made it possible to include partially coherent beams in the same methodology. For the design of high-performance systems, the inclusion of higher-order mode dispersion must be fully understood, the vector properties must be recoverable, and the paraxiality on which the methodology rests must be critically assessed. The authors emphasize these aspects and present a single systematic formulation embracing all the elements     

Skin optics

Quantitative dosimetry in the treatment of skin disorders with (laser) light requires information on propagation of light in the skin related to the optical properties of the individual skin layers. This involves the solution of the integro-differential equation of radiative transfer in a model representing skin geometry, as well as experimental methods to determine the optical properties of each skin layer. These activities are unified under the name skin optics. This paper first reviews the current status of tissue optics, distinguishing between the cases of: dominant absorption, dominant scattering, and scattering about equal to absorption. Then, previously published data as well as some current unpublished data on (human) stratum corneum, epidermis and dermis, have been collected and/or (re)analyzed in terms of absorption coefficient, scattering coefficient, and anisotropy factor of scattering. The results are that the individual skin layers show strongly forward scattering (anisotropy factors between 0.7 and 0.9). The absorption and scattering data show that for all wavelengths considered scattering is much more important than absorption. Under such circumstances, solutions to the transport equation for a multilayer skin model and finite beam laser irradiation are currently not yet available. Hence, any quantitative dosimetry for skin treated with (laser) light is currently lacking.     

High-density integrated optics

This paper presents two dimensional (2-D) finite difference time domain (FDTD) simulations of low-loss right-angle waveguide bends, T-junctions and crossings, based on high index-contrast waveguides. Such structures are essential for the dense integration of optical components. Excellent performance characteristics are obtained by designing the waveguide intersection regions as low-Q resonant cavities with certain symmetries and small radiation loss. A simple analysis, based on coupled mode theory in time, is used to explain the operation principles and agrees qualitatively with the numerical results     

相位共轭光学

本文介绍了相位共轭光学的基本概念，综述了产生相位共轭波的各种非线性光学技术，并讨论了它们之间的关系。     

Guided wave optics

Phenomena associated with the propagation and manipulation of light in thin-film dielectric waveguides are presently the object of considerable research effort, directed toward possible applications in communications and information processing. The theory of dielectric waveguide modes is reviewed, and the topics of directional coupling, input-output coupling, modulation, and distributed feedback laser sources are treated on the basis of coupled-mode theory. A summary of experimental results for each of the guided-wave optical phenomena covered by the theory is also presented.     

折反式周视红外成像系统光学设计

为增大周视成像系统视场的同时有效降低红外光学系统的复杂度,采用折反式光学结构,通过反射镜及透镜光焦度的合理分配,引入衍射面。分别设计了视场为360°×（-40°～50°）的折反式一次成像非制冷红外周视成像光学系统及视场为360°×（-30°～50°）的折反式二次成像光学系统。其工作波段为8～12 μm,光学系统F数为1.2。该系统可实现360°全方位和一定俯仰角度范围内凝视成像。设计结果表明,该系统的结构简单紧凑,后截距大,成像良好,在空间频率20 1p/mm处的调制传递函数(Modulated Transfer Function, MTF)值大于0.4,能满足应用需求。     

Digital computing with optics

Some of the current uses of optics in digital computing such as storage and networking, and the projected uses of optical interconnects are described. Several architectures that are being explored for optoelectronic computing are also described. These architecture are based on either the speed or the parallelism that is possible with optical systems. One or more of these architectures should prove fruitful within the next five years     

Physical optics inverse diffraction

A general method for solving the inverse diffraction problem is presented. It is based on an identity of Bojarski which states thatgamma(x)andGamma(p)are a Fourier transform pair. Heregamma(x)is the characteristic function of the target (gamma=1inside the target,gamma = 0outside),p = (2omega/c)J,omegais the frequency,Jis a unit vector specifying the aspect, andGamma(P)can be obtained by measurement of the backscattered electromagnetic far field at frequencyomega = (c/2)|P|and aspectJ=|p|^{-1}p. If data is obtained in any subsetDofpspace, the method yields partial or complete information about the target geometry. It is used to rederive earlier results very simply and to obtain a significant new solution, in which the target geometry is completely determined using frequencies only in a practical frequency band and aspects in a narrow cone.     

Measurements in fiber optics

Recent advances in optical-fiber technology dictate that attention must be given to establishing accurate and precise measurement techniques. In this paper measurements currently employed to determine the characteristics of optical fiber waveguides are reviewed. Included in the review are techniques for measuring attenuation, delay distortion, refractive-index profile, fiber diameter, and mechanical strength. Since establishment of accurate measurement procedures cannot be accomplished without some knowledge of the physical mechanisms controlling the parameters to be measured, a brief review of the dominant causes of attenuation and modal delay in fibers is also included.     

Fiber optics without fiber

Low-power infrared beams, which do not harm the eyes, are the means by which free-space optics (FSO) technology transmits data through the air between transceivers, or link heads, mounted on roof-tops or behind windows. It works over distances of several hundred meters to a few kilometers, depending upon atmospheric conditions. The authors believe that FSO could be the ultimate solution for high-speed residential access. Instead of hybrid fiber-coax systems, hybrid fiber-laser systems may turn out to be the best way to deliver high data rates directly to the home