利用單晶摻釹釔鋁石榴石晶體實現拍頻可調式正交偏振雙頻的自鎖模雷射

Abstract

為實現正交偏振之雙頻自鎖模雷射，本實驗以半導體雷射端面激發的架構，使用雙面鍍膜的摻釹釔鋁石榴石(Nd：YAG)單晶(monolithic)晶體，並透過機械應力和熱應力的影響，促使等向性晶體產生出雙折射性，造成頻率分裂的現象，產生正交偏振雷射光。並且在時域上觀察到兩正交偏振的拍頻(beating)現象，實驗中透過改變外加應力或者冷卻溫度，可以有效地達到調整拍頻的目的。

To achieve an orthogonally polarized dual-frequency self-mode-locked laser, a diode-end-pumped monolithic Nd:YAG crystal is utilized. According to the influence of mechanical stress and thermal stress, property of the birefringence in the isotropic gain medium can be observed and will spilt the laser frequency into two orthogonal eigenstates. The beat frequency between two orthogonally polarized mode-locked states is experimentally obtained and measured. It is experimentally verified that the beat frequency can be tuned by the external force and the cooling temperature on the Nd:YAG crystal.