Spectral properties of a two-dimensional resonant metal-dielectric photonic crystal

We have studied the transmission spectra of resonant two-dimensional photonic crystals of two types, one of which consists of nanocomposite cylinders that form a square lattice in vacuum and the other of which consists of cylindrical holes that form a square lattice in nanocomposite matrix. The nanocomposite consists of metallic nanospheres that are dispersed in a transparent matrix and is characterized by an effective resonant dielectric permittivity. We show that, depending on the position of the resonant frequency of the nanocomposite with respect to the boundaries of the band gap, there arises either an additional transmission band in the transmission spectrum in the band gap or an additional band gap in the continuous spectrum of the photonic crystal. As the structural and geometric parameters of the system change, both the additional transmission band and the additional band gap are considerably modified. We analyze particular features of the spatial distribution of the electromagnetic field intensity in crystals. The considered effects can be used to extend the possibilities of creating new photonic crystals with specified properties.     

Spectral characteristics for a fiber grating external cavity laser

A numerical investigation has been carried out on the influence of the antireflection (AR) coating of laser, the coupling efficiency of laser and fiber (), and the reflectivity of fiber grating (R _g) on the side-mode suppression ratio (SMSR) of the fiber grating external cavity laser (FGECL). The FGECL was fabricated by the assembly of the multimode Fabry–Perot (FP) laser chip and fiber grating. The results showed that the FGECL with a lower AR coating, higher and R _g exhibited a better SMSR. A comparison of the SMSR dependence on the and R _g showed that SMSR increased more rapidly with increasing than SMSR for R _g. These spectral characteristic studies of the SMSR dependence on the device parameters of the AR coating, , and R _g may provide useful device designs for the practical fabrication of a FGECL for use in dense wavelength division multiplexing (DWDM) applications.     

Effect of a dielectric film on the characteristics of an open Fabry-Perot resonator cavity

It is demonstrated that placing a thin dielectric film inside the cavity of an open Fabry-Perot resonator, at an angle to its axis, will remove the polarizational degeneracy of the principal TEM_q00 oscillation modes. Upon excitation of such a resonator cavity by a plane wave, the reflected electromagnetic field is in general elliptically polarized. The shape of the resonance curve depends on the thickness of that film, on its orientation inside the cavity, on the conditions under which the cavity has been excited, and on the conditions under which the reflected signal appears in the receiver. Changing the polarization plane of the incident plane wave does not result in a smooth variation of the resonator Q factor.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 21, No. 11, pp. 1648–1652, November, 1978.     

Motion of dissipative solitons in a laser cavity with a smooth transverse inhomogeneity

The effect of the inhomogeneity gradient in a large-aperture class A laser with a saturable absorber on the transverse motion of dissipative solitons and their clusters in the laser cavity is analytically and numerically studied. A soliton with a nonzero topological charge is found to move rectilinearly in the steady-state regime but in a direction that differs from the direction of the cavity length gradient, which is connected with a nontrivial internal structure of the soliton. The steady-state motion of soliton clusters can be curvilinear, including translational and rotational motions of their center.     

具有突变结构开放腔的矩阵分析

利用模式展开与场匹配原理，建立了突变波导的散射矩阵(S参数矩阵)，在此基础上分析研究了具有突变结构的波导开放式谐振腔，并由矩阵级联建立了开放腔总的S参数矩阵.通过Matlab编制计算程序对具有多级突变结构的开放式输出腔进行了数值计算和分析，并通过与实验数据和软件模拟的结果比较对该方法得到的数据结果进行了验证. 关键词： 回旋管 开放式谐振腔 突变结构 S参数矩阵     

C波段磁绝缘线振荡器开放腔高频特性分析

建立了C波段磁绝缘线振荡器开放腔模型,通过监测宽带激励源的响应计算出开放腔的谐振频率和有载品质因数。用时域有限差分法计算了不同的径向位置一个周期内的径向电场随纵向距离的变化。计算表明：0~4.1 cm区电场很小但不为零;4.1~11.5 cm区域电场呈现驻波特性;在11.5~20 cm区域电场分布比较复杂,表现两个性质,一是驻波场过渡到行波场,二是从周期性加载圆柱谐振腔的TM00模过渡到同轴线的TEM模;在20~36.85 cm区域电场每经过1/4周期向右传播1/4波长,表现出行波特性。由此根据该计算结果将开放腔中的场从左到右分成4个区：截止区、驻波区、过渡区和行波区。最后根据定义计算了开放腔的固有品质因数和有载品质因数。     

C波段磁绝缘线振荡器开放腔高频特性分析

 建立了C波段磁绝缘线振荡器开放腔模型,通过监测宽带激励源的响应计算出开放腔的谐振频率和有载品质因数。用时域有限差分法计算了不同的径向位置一个周期内的径向电场随纵向距离的变化。计算表明：0~4.1 cm区电场很小但不为零;4.1~11.5 cm区域电场呈现驻波特性;在11.5~20 cm区域电场分布比较复杂,表现两个性质,一是驻波场过渡到行波场,二是从周期性加载圆柱谐振腔的TM00模过渡到同轴线的TEM模;在20~36.85 cm区域电场每经过1/4周期向右传播1/4波长,表现出行波特性。由此根据该计算结果将开放腔中的场从左到右分成4个区：截止区、驻波区、过渡区和行波区。最后根据定义计算了开放腔的固有品质因数和有载品质因数。     

Electronic transport through an open elliptic cavity

This paper computes the conductance of an open ellipse cavity and discusses the effect of finite leads on conductance. The lead introduces mode coupling with bound states in the cavity which contributes to Fano resonant line shapes in conductance. By examining the resonant states in the cavity, the effects of state mixing and annular probability distribution of wave function due to the presence of leads are found. The results have been compared with the transport properties of other systems. The finite leads result in two effects, i.e. the evanescent mode contribution and additional oscillations, to the conductance.[第一段]     

Spectral and diffraction characteristics of open cavities with gyrotropic (plasma) inclusions

We develop a mathematically rigorous electrodynamic model which describes the spectral characteristics of 2-D open cavities with circular gyrotropic plasma cylinders. As a result, we construct and substantiate a numerical algorithm for calculating the spectrum of natural frequencies of this type of the structure. Oscillatory processes in a 2-D two-mirror cavity with circular plasma cylinders are analyzed in the bands in which hybrid intertype oscillations occur.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 39, No. 9, pp. 1161–1175, September, 1996.     

有源耦合腔激光器锁模特性研究

本文在理论上首次发现有源耦合腔激光器的自启动锁模和时域调制特性,并对其进行了全面的分析和计算.对有源耦合腔激光器的自启动锁模机制和时域调制特性给予详尽的数值计算结果和清晰的物理图象解释,提出在有源耦合腔锁模激光器中可用连续泵浦源代替锁模泵浦源,而且有产生更短的光脉冲可能性.     

Spectral beam combining of a broad-stripe diode laser array in an external cavity

The outputs from an 11-element, linear diode laser array with broad stripes have been beam combined into a single beam with a beam quality of ~20x diffraction limited in the plane of the junction. This beam combining was achieved by use of a common external cavity containing a grating, which simultaneously forces each array element to operate at a different, but controlled, wavelength and forces the beams from all the elements to overlap and propagate in the same direction. The power in the combined beam was 50% of the output from the bare laser array.     

Wavelength tuning characteristics of a fabry-perot semiconductor laser with an external short cavity

Wavelength tuning characteristics of a Fabry-Perot semiconductor laser with an external short cavity are analyzed, in which the oscillation wavelength can be changed by slightly altering the external cavity length. Analysis is based on rate equations for an optical power and carrier density. It is shown that the wavelength tuning range is dominated by a change of carrier density through the effect of carrier-induced refractive index change in the active layer of a laser diode. This depends on effective coupling coefficients of the optical field iteratively reflected back to the laser diode by the external mirror, and on reflection coefficients of an anti-reflection coated laser facet and the external mirror which compose the external cavity. The effective coupling coefficient is also derived using the waveguide theory and Kirchhoff ’s theory. Finally, an unstable condition which may limit a stable wavelength tuning range is shown by results of a linear stability analysis of rate equations.     

170 GHz缓变截面开放式谐振腔传播特性模拟

在数值计算方法的基础上,编程模拟了高次模式TE31,12模在传统及改进型开放式缓变截面谐振腔的传播特性,计算了开放式缓变截面谐振腔的绕射品质因数,研究了改进型缓变截面谐振腔连接段的曲率半径对绕射品质因数的影响。结果表明,连接段曲率半径越大,绕射品质因数值越小。为了证明结论的正确性,利用仿真软件HFSS对另一工作于低次模TE0,1模的改进型缓变截面谐振腔进行仿真计算,并和编程计算结果比较,也得到了同样的结论。     

Observation of resonance trapping in an open microwave cavity

The coupling of a quantum mechanical system to open decay channels has been theoretically studied in numerous works, mainly in the context of nuclear physics but also in atomic, molecular, and mesoscopic physics. Theory predicts that with increasing coupling strength to the channels the resonance widths of all states should first increase but finally decrease again for most of the states. In this Letter, the first direct experimental verification of this effect, known as resonance trapping, is presented. In the experiment a microwave Sinai cavity with an attached waveguide with variable slit width was used.     

170 GHz缓变截面开放式谐振腔传播特性模拟

在数值计算方法的基础上,编程模拟了高次模式TE31,12模在传统及改进型开放式缓变截面谐振腔的传播特性,计算了开放式缓变截面谐振腔的绕射品质因数,研究了改进型缓变截面谐振腔连接段的曲率半径对绕射品质因数的影响。结果表明,连接段曲率半径越大,绕射品质因数值越小。为了证明结论的正确性,利用仿真软件HFSS对另一工作于低次模TE0,1模的改进型缓变截面谐振腔进行仿真计算,并和编程计算结果比较,也得到了同样的结论。     

Spectral characteristics of an annular electrodeless discharge

Results are given for the 4844 Å spark line of Xe in long cylindrical tubes. The mean electron temperature is deduced for a discharge in He, and the effects of He on the intensity of the Ne line at 6328 Å are considered.I am indebted to Yu. V. Troitskii for direction and to N. F. Votrin for assistance.     

Focusing characteristics of a diffraction grating in an open resonator

Radiophysics and Quantum Electronics -