共查询到20条相似文献,搜索用时 15 毫秒
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It is shown that propagation in an unstable resonator can be expressed in a form similar to that applicable to a plane-mirror
resonator, but with the magnification appearing as a scaling parameter. 相似文献
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正支共焦非稳腔在出光过程中易受环境扰动而造成腔长失调,易受热积累影响而使腔镜变形,从而使输出光束产生离焦像差和部分其它像差。为了实现对离焦像差的校正,针对不同的产生原因,提出了2种离焦像差特性分析方法:一为腔镜相对位置失调引起的离焦像差特性理论分析方法,它是另一种分析方法的基础;二为腔镜变形引起的等效腔长变化导致的离焦像差特性分析方法,它是实际激光器中的主要分析方法。得到了离焦像差与腔长的特性关系和离焦像差与腔镜变形量之间的特性关系。研究表明:腔长改变和腔镜变形对离焦像差的影响本质是一样的,都是改变了谐振腔的共焦点位置;腔长改变或腔镜矢高变化与离焦像差都成近似的线性关系。实验验证了离焦像差特性分析方法的有效性,最后指出离焦像差特性可作为激光器中离焦像差动态补偿的有效依据。 相似文献
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The thermal lensing properties of stable and unstable resonators are compared and rules are given for the design of optimized unstable resonators containing a focusing rod. Experimental verification with a high-power Nd: YAG system proved that for unstable resonators the restricting relationship between beam quality and output power no longer holds. Careful resonator design enables high output power to be extracted with unstable resonators without destroying the output couplers. 相似文献
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The thermal lensing properties of stable and unstable resonators are compared and rules are given for the design of optimized unstable resonators containing a focusing rod. Experimental verification with a high-power Nd: YAG system proved that for unstable resonators the restricting relationship between beam quality and output power no longer holds. Careful resonator design enables high output power to be extracted with unstable resonators without destroying the output couplers. 相似文献
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In order to compensate for thermal lensing in Nd : YAG rod active media, placed in unstable resonators with a super-Gaussian reflectivity profile of the output mirror, a deformable thin glass plate was used as the rear mirror. Unstable resonators with a magnification of M = 1.8 and with one and two Nd : YAG rods inside were investigated. By a proper variation of the radius of the thin glass plate, the magnification of the resonator was maintained constant by varying the refractive powers of the rods. For compensated resonators, the output energy of the laser working at 10 Hz repetition rate and pump energies up to 50 J per pulse was close to those obtained for a 1 Hz repetition rate. 相似文献
7.
Yang Z Chak P Bristow AD van Driel HM Iyer R Aitchison JS Smirl AL Sipe JE 《Optics letters》2007,32(7):826-828
Highly efficient second-harmonic generation can be achieved by harnessing resonance effects in microring resonator structures. We propose an angular quasi-phase-matching scheme based on the position dependence of polarization inside the ring resonator. 相似文献
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Feth N Linden S Klein MW Decker M Niesler FB Zeng Y Hoyer W Liu J Koch SW Moloney JV Wegener M 《Optics letters》2008,33(17):1975-1977
We present experiments on second-harmonic generation from arrays of magnetic split-ring resonators and arrays of complementary split-ring resonators. In both cases, the fundamental resonance is excited by the incident femtosecond laser pulses under normal incidence, leading to comparably strong second-harmonic signals. These findings are discussed in terms of Babinet's principle and in terms of a recently developed microscopic classical theory that leads to good agreement regarding the relative and the absolute nonlinear signal strengths. The hydrodynamic convective contribution is found to be the dominant source of second-harmonic generation--in contrast to a previous assignment [Science 313, 502 (2006)]. 相似文献
10.
We obtained high-quality lowest-loss-mode lasing in quasi-stadium laser diodes having unstable resonators that consisted of two curved end mirrors and two straight sidewall mirrors. The laser diodes were fabricated by applying a reactive ion etching technique to a metal-organic chemical-vapor deposition-grown graded-index separate-confinement heterostructure single-quantum-well GaAs/AlGaAs structure. The electrode contact area of the laser diodes was formed along unstable periodic orbits, along which the optical beams are localized. Highly directional fan-out beams corresponding to the numerically obtained lowest loss mode were emitted from the end mirrors under CW operation at room temperature. 相似文献
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Colins公式将几何光学和波动光学联系在一起,能以简单的形式描述相干光在复杂光学系统中的传输,但忽略了光学系统中一些光学元件的衍射损耗。当Colins公式用于激光谐振腔的本征模式计算时,其适用程度与被忽略腔镜的有效菲涅尔数有关。本文用数值方法求解了两组谐振腔本征积分方程,一组应用Colins公司推导,另一组用菲涅尔-惠更斯衍射积分推导,结果表明:对稳定腔Colins公式基本适用;对非稳腔,当被忽略腔镜的有效菲涅尔数>1时,原则上可以用,当被忽略腔镜的有效菲涅尔数<1时不适用;对有源非稳腔基本适用。 相似文献
13.
R. M. Hofstra M. J. Zwegers F. A. van Goor W. J. Witteman 《Optics Communications》1998,150(1-6):163-169
The divergence of a long pulse, low gain XeCl excimer laser has been improved using confocal positive branch unstable resonators with variable reflectivity mirrors as outcouplers. With variable reflectivity unstable resonators, nearly diffraction limited beams are obtained. Variable reflectivity resonators lead to high brightness beams (9.1
10
W/(cm
sr)). Different reflection profiles were studied with respect to their influence on the beam quality and the energy extraction. 相似文献
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E. K. Gorton 《Optics & Laser Technology》1983,15(5):274-275
A problem which arises when one considers continuously coupled unstable resonators is that the beam divergence due to geometrical effects is usually large. This note describes a simple remedy which can be applied in most cases. 相似文献
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We investigate the thermo-optic effects on second harmonic generation (SHG) in AlGaAs/AlO(x) microring (MR) waveguides. We show that SHG can be utilized to enhance the thermal sensitivity of MRs. This sensitivity makes this structure appropriate for thermal modulation and switching of optical signals or temperature sensing. 相似文献
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A novel mechanism is proposed for the generation of self-similar structure over a limited range of length scales. Our mechanism, which we call the monitor-outside-a-monitor effect, comprises repeated magnification and addition of small-scale structure. We invoke this mechanism to explain recent observations of fractal structure in the eigenmodes of unstable optical resonators [G. P. Karman et al., Nature (London) 402, 138 (1999)]. 相似文献