Fabrication and Measurement of Diffractive Elements for Filtering
陸 懋 宏
|關鍵字:||繞射光學元件;濾波繞射元件;diffractive optical element;Diffractive Elements for Filtering|
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.