具有非对称高斯反射率相位共轭光腔的基模

由高斯光束泵浦的四波混频相位共轭反射镜(PCM)具有横向高斯分布的反射率.这种分布是空间非对称的.本文给出这种PCM(包括自泵浦情况)的光束变换矩阵,把它用于自泵浦相位共轭光腔的分析;得出腔内振荡是椭圆高斯光束的结论.     

Sensitivity of dielectric resonators to environmental conditions

The effects of the variation of different physical parameters in a simple, shielded dielectric resonator structure is studied. The study uses an approximate analytical expression for the resonance frequency stability of dielectric resonators. The results are of special importance in applications where the dielectric resonators are subjected to varying environmental conditions.     

A theoretical and experimental investigation of the modes of optical resonators with phase-conjugate mirrors

We present an analysis of resonator properties for a cavity bounded by a phase conjugate mirror, which is generated by a degenerate four-wave nonlinear optical interaction. Using a ray matrix formalism to describe the conjugate mirror, resonator stability conditions are derived. Longitudinal and transverse mode characteristics are discussed. Results are compared with an experiment where laser oscillation was observed at 6943 Å using carbon disulfide as the nonlinear interacting medium comprising the phase conjugate mirror.     

腔内扰动对虚共焦腔模式的影响及Zernike像差拟合

为实现高功率或高能激光器输出良好的光束质量和能量,分析了腔内像差扰动对非稳腔模式的影响,采用数值迭代法理论计算了腔内倾斜扰动对无源虚共焦非稳腔输出模式强度和相位分布的影响,并采用Zernike模式法对光束相位进行了像差拟合分解,得到了前35阶像差系数,通过进一步计算得到点扩散函数和环围能量曲线等,从而全面了解输出光束质量.结果表明,对小菲涅耳数虚共焦型非稳腔,腔内倾斜扰动不仅带来输出光强分布的不均匀性,且对相位分布有明显的影响,使相位中的一些高阶Zernike像差如A_3,A_7和A_(10)等增大.计算结果对研究高能激光器腔内像差校正有一定参考意义.     

High-temperature superconductor resonators and phase shifters

High-T_c resonators and hybrid digital phase shifters have been designed, fabricated, and tested. The YBa₂Cu₃O_7-δ (YBCO) films used were off-axis sputtered onto 0.5-mm-thick [100] LaAlO₃ substrates and have surface impedances at 10 GHz as low as 20 μΩ at 4.2 K and 300 μΩ at 77 K. The dielectric constant of the LaAlO₃ substrates was measured using straight-line and ring resonator techniques. The superconductor straight-line resonator, which uses silver as its ground plane, has a moderately high Q factor and has an electromagnetic feedthrough level below -65 dB up to 10 GHz. The authors also report the first demonstration of a semiconductor/superconductor microwave digital phase shifter. YBCO film was used to form the circuit, with semiconductor p-i-n diodes serving as switches. A 4-b superconductor phase-shifter design is also presented along with simulation results that indicate maximum total insertion loss (which occurs with all bits forward-biased) at 77 K to be 1.1 dB at 10 GHz     

相位共轭光腔的基本物理性质

用一面由四波混频非线性相互作用产生的相位共轭镜(PCM)和另一面真镜(RM)组成的相位共轭光腔(PCR),将会得到十分优良的性质。 为了描写PCM的运转特性,Yariv等和Siegman等定义了该元件光线变换矩阵的第一形式(M_(PCMI));并已由此得出PCR若干有用的性质。但,M_(PCMI)并没有包含相位共轭运算,ABCD定律不再适用,需要人为地加置共轭,给腔模的分析带来很大的困难。 本文定义了PCM变换矩阵的第二形式(M_(PCMH))。所有的变换(包括共轭运算)均包含在M_(PCMH)的矩阵元中,普通的ABCD定律仍然适用,从而非常简洁地导出了PCR的基模。进一步运用M_(PCMH),得到了基模的微扰稳定性、高价模和非简并模。     

相位共轭镜和相位共轭腔

本文使用矩阵光学方法,分析了下述论题:1.相位共轭镜的两类变换矩阵及其物理意义;2.相位共轭腔与常规稳定腔的比较;3.相位共轭腔的模参数;4.有频移的相位共轭腔;5.相位共轭腔的稳定性,并提出了一些问题加以讨论。     

腔内扰动对虚共焦腔模式的影响及Zernike像差拟合

为实现高功率或高能激光器输出良好的光束质量和能量,分析了腔内像差扰动对非稳腔模式的影响,采用数值迭代法理论计算了腔内倾斜扰动对无源虚共焦非稳腔输出模式强度和相位分布的影响,并采用Zernike模式法对光束相位进行了像差拟合分解,得到了前35阶像差系数,通过进一步计算得到点扩散函数和环围能量曲线等,从而全面了解输出光束质量.结果表明,对小菲涅耳数虚共焦型非稳腔,腔内倾斜扰动不仅带来输出光强分布的不均匀性,且对相位分布有明显的影响,使相位中的一些高阶Zernike像差如A3,A7和A10等增大.计算结果对研究高能激光器腔内像差校正有一定参考意义.     

菱体型相位延迟器对入射角灵敏性的研究

为了清楚地了解菱体型消色差λ/4相位延迟器对入射角i变化的灵敏性随折射率n变化的规律,利用全反射相变公式详细推导出器件对入射角i变化的灵敏性与折射率n的关系式,并做出了理论曲线。可见,随着折射率n的增加,器件对入射角i的变化更加灵敏。结果表明,设计器件时应尽量避免选择高折射率材料。在分析相位延迟量的测量误差时,这个应用也是很有价值的。     

弱高斯光阑近似和相位共轭腔

本文证明了在弱高斯光阑近似下,相位共轭腔中不存在确定模,只有当非弱高斯光阑处于腔中或相位共轭镜之前,相位共轭腔才具有确定的模。     

含虚元件相位共轭腔的热稳定性

本文介绍了一种CO2激光测距机用智能化计数逻辑及控制电路,该电路也可用于一般脉冲式激光测距机。     

Orthogonality properties of transverse eigenmodes of phase conjugate optical resonators

The orthogonality properties of the transverse eigenmodes of optical resonators which have phase conjugate mirrors at both ends are derived. As in conventional resonators and also resonators with only one phase conjugate mirror, it is shown that the transverse eigenmodes are essentially biorthogonal, a relation which is satisfied between the set of modes propagating in one direction around the resonator and the adjoint set of modes propagating in the reverse direction.     

Modes, phase shifts, and losses of flat-roof open resonators

The integral equation of a "flat-roof resonator" is solved by the Fox and Li method of iteration in a number of particular cases. Mode patterns, phase shifts, and power losses are derived. A good overall agreement is found with the approximate theory previously developed by Toraldo di Francia. Some experimental tests carried out on a microwave model give a further confirmation of the theoretical predictions.     

Effects of small-scale phase perturbations on laser oscillator beam quality

A simplified analysis is presented for predicting the effects of small-scale intracavity phase perturbations or scattering centers on the power output and beam quality of high-power laser oscillators. The small-scale perturbations are viewed as scattering energy from the unperturbed lowest order transverse mode of the cavity into numerous higher order transverse modes. These modes are, unfortunately, then regeneratively amplified within the laser cavity. This produces only a small change in the effective output coupling and the total power output from the perturbed laser cavity, but causes a serious deterioration in the far-field brightness and on-axis intensity of the output beam.     

利用阵元相位和位置扰动形成零陷的技术

论文提出了一种利用阵元相位和位置扰动相结合形成零陷的方法,该方法假设阵元相位扰动和位置扰动都很小,因而能够利用线性化处理的方法形成零陷,相对于非线性处理方法,计算量大大降低.仿真表明单独使用阵元位置扰动或者相位扰动都不能够形成深度零陷,而采用论文提出的零陷技术,能够在多个干扰源方向形成深度零陷,而不影响主瓣,其零陷性能优于位置扰动非线性化处理方法.在此基础上,为了进一步减少需要控制的阵元数,提高系统鲁棒性,论文仿真分析了阵元位置选择性扰动和相位扰动相结合的零陷性能.仿真表明采用该方法,其性能优于文[4]中选择性非线性处理方法的性能.     

Application of a phase-conjugate Brillouin mirror to generation ofhigh-quality variable-duration KrF pulses

Phase conjugation by Brillouin scattering in SF₆ gas has been implemented on a two-pass KrF amplifier to provide near-diffraction-limited output pulses having a very low background level of amplified spontaneous emission. The pulse duration is variable between 1 and 10 ns by simply attenuating the input pulse. These pulses have also been used for the generation of much shorter duration pulses by truncated Brillouin scattering at the surface of cyclohexane     

弱高斯光阑近似和相位共轭腔的基本性质

对弱高斯光阑近似的物理意义和相位共轭腔(PCR)的基本性质作了详细讨论,使用传播矩阵方法推导出了PCR补偿腔内畸变的条件。PCR具有本质上不同于常规腔的特点。     

相位共轭激光器的能量反馈与双稳态

通过数值求解稳态下的PCL输运方程，研究了三种形式的能量反馈型PCL的特性。     

Applying the Babinet principle to asymmetric resonators

Complementary asymmetric split resonators (CASRs), which feature a sharp passband response are proposed. The design is derived by applying the Babinet principle to asymmetric split resonators (ASRs). The complementary nature of the CASR and the ASR structures is discussed in detail with regard to the transmission and reflection response as well as to the electric and magnetic field distributions.     

Application of inhomogeneous dielectric loading to coaxial resonators

A technique for improving the Q factor of air-filled coaxial resonators by inhomogeneous dielectric loading is reported.