濾波繞射元件的製作及量測

Abstract

本論文是以繞射理論為基礎，利用繞射光學元件本身之特殊色散效果來設計濾波繞射元件，使其能達到窄波段濾波與聚焦的功能，以矽做為基片，並以最佳化演算法進行純相位光學繞射元件的設計。 把所設計的元件，分為八階量化，使其可以利用半導體製程技術，去製作濾波繞射元件，並利用ZYGO去檢視其製作品質。 最後把量測所需要利用到的各種不同光源，以實驗室現有的YAG脈衝雷射利用OPO系統，形成不同近紅外波長光源，利用此光源建立的光學系統量測其繞射效率，把光源換作ASE(1520nm~1570nm)以紅外CCD來分析其光學性質。

In this thesis, based on diffraction theory we developed a diffractive optical element (DOE), which combines the functions of a narrow-band filter and a focal lens. This DOE was made on the silicon substrate, which transmits and focuses the light on the axial point with the wavelength bandwidth of 6 nm, centered at the 1.533μm wavelength. This pure phase type diffractive optical element was designed and optimized with an iterative method. In order to fabricate this DOE with the VLSI semiconductor technique, the surface structure of DOE was quantized by eight levels. The surface profile was measured by ZYGO. The filtering efficiency and the optical properties of the DOE were measured by two systems. One used optical parameter oscillator (OPO), pumped by a YAG pulsed laser, as near infrared light source (1.2μm-1.8μm), and an energy meter as detector. Another used an ASE (1.52μm-1.57μm) light source and a near infrared CCD camera to analyze the optical properties of the DOE.