半導體雷射激發式被動鎖模固態雷射之研究

Abstract

近年來關於Nd:YVO4與Nd:GdVO4的相關論文中指出，Nd:GdVO4的晶體特性優於Nd:YVO4，但目前尚未有人用Nd:GdVO4來做連續波鎖模方面的研究；因此在本論文中，我們將研究和比較這兩種增益介質，並以實驗和理論模擬來探討不同增益介質與非線性鏡 (NLM)和半導體飽和吸收鏡(SESAM)鎖模機制的相互關係。本論文以非線性晶體的非線性轉換修正了Stankov的理論，並以半導體飽和吸收鏡的非線性變化討論半導體飽和吸收鏡中調變深度與鎖模機制的關係。而且，我們所建構出的理論已可定性地描述非線性鏡鎖模和半導體飽和吸收鏡鎖模的變化趨勢。

The study of Nd:YVO4 and Nd:GdVO4 lasers pumped by a continuous-wave diode laser has increased in recent years. Even though Nd:GdVO4 has superior crystal properties than Nd:YVO4,its efficiency on the diode-end-pumped cw mode-locked laser has never been investigated. In this paper we study and compare the two different gain mediums, Nd:YVO4 and Nd:GdVO4, on the cw mode-locked laser with both the nonlinear mirror (NLM) and semiconductor saturable absorber mirror (SESAM) mechanisms. These two mode-locked mechanisms as well as the ultra-short pulse generation theory will be investigated and presented with the theoretical simulations and experimental results. Physical criteria for the characteristics of both NLM and SESAM will also be developed in this paper. Taking into account the nonlinear effects of nonlinear crystal and SESAM, we intend to modify Dr. Stankov’s theory in NLM cw mode-locked lasers and present new parameters for generating short pulse in SESAM.