鉭酸鋰非線性光子晶體與鎳擴散波導之黃光雷射產生研究

Abstract

本論文以非線性晶體鉭酸鋰及鈮酸鋰為材料，藉由在晶體中研製出週期性極化反轉結構，產生一光柵動量，並且製作鎳擴散波導，使1122nm紅外光因準相位匹配而倍頻輸出黃光。 我以高壓致極化反轉的方式，分別於鈮酸鋰和鉭酸鋰上，製作單週期的結構。並在已反轉的結構上，利用高溫擴散的方式，製作了鎳擴散通道和平面波導，利用顯微鏡觀察的方式，得知大致的擴散深度，鈮酸鋰鎳擴散波導為8μm，鉭酸鋰為3.5μm。 光學量測的部分，我分別以研磨端面法和影像法量測了鈮酸鋰和鉭酸鋰鎳擴散波導的光損耗值，得知鈮酸鋰的通道波導光損耗約為3dB/cm，而鉭酸鋰的平面波導光損耗約為11dB/cm，而倍頻黃光的量測上，入射光為寬頻紅外光時，黃光頻譜半高寬約為1nm，溫度頻寬為10oC，而入射光能量2mW時，可以產生5μW的能量。

The thesis discusses the fabrication issues and optical measurement of periodically poled structure with nickel-diffused waveguide on congruent lithium niobate(CLN) and congruent lithium tantalite(CLT) to let a 1122nm infrared laser convert into a 561nm yellow laser by using the quasi-phase-matched second-harmonic-generation (QPM-SHG) technique. The periodically reversed LN and LT samples are fabricated by high voltage poling method. After metal deposition and proper heat treatment, the nickel-diffused waveguide was formed. The diffusion layer can be observed by microscope. Under transmission light and tuning the polarization, we can get a rough number of the depth. The depth of nickel diffused channel waveguide on lithium niobate is about 8μm, and the depth of nickel diffused planar waveguide on lithium tantalate is about 3.5μm. For optical loss measurement, we measure the loss of nickel diffused waveguide on both substrates by cut-back method and imaging method. The loss of Ni-diffused channel waveguide on LN is about 3dB/cm and the loss of Ni-diffused planar waveguide on LT is about 11dB/cm. Moreover, the SHG characteristics for a single-peiod 0.5mm congruent lithium tantalite with Ni-diffused channel waveguide shows acceptance temperature bandwidth 10 oC with ouput power is 5μW .