摘要
近年來對雷射越來越普及應用,讓如何保護敏感的偵測器或人眼成為一個重要的研究方向,就現階段而言普遍使用非線性吸收材料來設計被動式光學限制器,被動式的光學限制器的好處在系統對入射能量的反應快,而且基於 ( )七能級模型的非線性吸收材料能提供很強的激發態吸收,有效的抑制入射能量,達到光功率限制的功能.
除了對材料的選擇,對於光學限制器還有另一個重要的設計方向,即限制器的幾何設計,不管是 的架構或雙聚焦的設計,他們設計的意義為在主要的材料前再放一個保護性質的材料,保護光學限制器不受高能量的雷射破壞而失去作用,並提高所能承受的能量門檻及光學限制器的 ( ).
由於有些 材料有很高的 比率,對於非線性吸收有很強的效應,實驗上我們使用了 和 作為驗證在 的理論下的光學限制器可行性,並說明整個實驗的流程.另外對於限制器還有一個重要的需求即整個系統的成像表現,有好的成像是讓接收者為人眼的光學限制器的設計重點.因為對於人眼而言光學限制器除了對能量抑制表現好外,成像是否清晰也是重點,尤其當限制器是應用在軍事用途上時.
最後在成像的原理上,希望能把光學限制器的像差減至最小,尤其在球差和像散上,改善整個系統的像差不僅能滿足我們成像品質的要求,理論上也能提高限制器在抑制能量上的表現,因此我們模擬了五種不同類型的設計方式來和原先直進式做比較,設計重點除了在成像比較外,還把整個系統長度縮短,以期在長度和成像品質上能優於直進式的系統.

Abstract
Due to the increasing demand of the high-power laser applications, devices protecting detectors or human eyes, optical limiters, become an important research direction in the recent years. Nonlinear absorbing materials are attractive in designing this type passive optics limiters. The advantage of the optics limiter in the passive form is the speedy response to the incidence energy. Designs based on the nonlinear absorbing material can offer very strong excited-state absorption, and effectively restrain incidence energy.
Besides the choice of nonlinear materials, there is another important issue in designing optics limiters, geometry. Different geometric arrangements, such as tandem structure and graded-density structure, have been proposed to achieve better limiting performance. The main purpose of those designs is creating a second protection for the chief absorption element. A dual-focus limiting design has demonstrated the best limiting performance with the price of increasing length. In this thesis we propose different designs to shorten the length as well as improving the imaging quality of this optical system.
Spherical aberration and astigmatism are the primary aberrations in this situation. We simulate five different kinds of folded designs to shorten the total length of the original design. We are able to come up with a design that preserves the performance and make the whole system more compact. It can be useful in military applications.

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