四色白光與低散斑雷射光源之研究

Abstract

本論文利用準相位匹配理論，研究非線性光學之頻率轉換。我們於厚度0.75mm的鉭酸鋰晶體製作出週期性極化反轉結構，達到準相位匹配而進行頻率轉換。 鉭酸鋰晶體結構設計分為兩部份的頻率轉換結構之串聯，其晶體總長度為20mm，其操作溫度為140度。第一部分為OPO結構，長為10mm，由532nm綠光作為泵浦光入射，經過晶體後進行頻率轉換，產生訊號光為1300nm與閒置光為900nm。第二部分為三組倍頻轉換與和頻轉換結構之並聯結構，長為10mm，各別為1300nm倍頻轉換成650nm紅光、900nm倍頻轉換成450nm藍光、1300nm與1064nm和頻轉換成585nm黃光。 由光學量測分析後，本實驗所輸出之白光的CIE 座標為(0.3626,0.3547,0.2827)，色溫為4835K。

This thesis is a study based on quasi-phase-matching frequency conversion in nonlinear optics. We fabricate periodically poled structures on 0.75mm thick congruent lithium tantalite(CLT) substrates to realize the condition of quasi-phase-matching (QPM) for frequency conversion. There are two QPM patterns cascadedon the CLT substrate of the structure on LT substrate at a crystal length of 20mm. The fist part in the above device is a 10mm-long PPLT structure for the optical parametric oscillation (OPO). It converts a 532nm pump green laser into a signal 1300nm wavelength and a idler 900nm wavelength. The second part contains the PPLT parallel three sets of structures of 10 mm length for the second-harmonic generation(SHG) and sum-frequency generation(SFG). It is designed for converting the 1300nm and 900nm wavelength into 650nm and 450nm SHG separately. And others, it is for combinig the 1300nm and the 1064nm into 585nm by the SFG process. After optical measurement, the CIE coordinates of the white laser is (0.3626,0.3547,0.2827). And, The correlated color temperature (CCT) is 4835K.