本論文提出以Fabry Perot Etalon做為雷射高斯光束發散角量測之研究，主要是利用高銳度係數之Fabry Perot Etalon對於雷射高斯光束發散角的變化，使得當入射角改變之掃描結果造成第一亮纹中強度e-1所對應兩點角度間距寬窄的改變，並配合曲線擬合的方式將雷射光之發散角度快速的量測出。本系統有著架構十分簡單、體積小、僅需單點量測和解析度高的優點。在雷射已達定溫狀態下，本系統的量測重複性之標準差為0.015 mrad、而系統量測解析度為0.021 mrad。A method for laser Gaussian beam divergence measurement by Fabry Perot etalon is proposed. The scan result by incident angle change correspond full width at half maximum of the first order fringe variation by high coefficient of finesse Fabry Perot etalon. With the curve fitting method, we can measure laser beam divergence quickly.Our system has advantage of simple structure, small size, high resolution and only single point measuring. The experimental results demonstrate that the resolution of the system is 0.021 mrad and the standard deviation of repeatability is 0.015 mrad.
