Quasi-Phase-Matching Second Harmonic Generation Green Laser with Large Temperature Bandwidth On PPMgO:LiNbO3
Date Issued
2010
Date
2010
Author(s)
Liou, Jiun-Wei
Abstract
This thesis reports the fabrication of periodically poled magne-sium-oxide-doped congruent lithium niobate (PPMgLN), to convert the 1064nm infrared laser into 532nm green light by using the technique of quasi-phase matching second harmonic generation(QPM-SHG).
We improved the fabrication technique on electric poling method of congruent lithium niobate. This method leads to the realization of periodically poled QPM structures on 0.5mm and 1mm thick MgO:LiNbO3 substrates. The smallest periods achieved in this work are (i) 6.91um for the 1st - order 、(ii) chirped-gratings for the 1st-order QPM device. For the 1mm thick substrate , the smallest periods we can make are (i) 6.96um for the 1st-order quasi-1D、(ii)13.8um for the 2nd–order QPM device.
For the characterization we measured SHG on PPMgLN with 5mm crystal length when pumped by a pulsed 1064nm laser of 159 MW/cm2 (180mW) with 5ns pulse width of 60um beam waist. The device exhibits 80mW green light output with conversion efficiency attain 46% . Second, the design of chirped grating structure with 5mm long are tested by a pulsed 1064 nm laser of 195 MW/cm2 (350mW) with beam radius 75um. The device exhibits 63mW green light output with the conversion efficiency 20%, and the acceptance temperature bandwidth is about 50 degree. In the same length, the acceptance temperature bandwidth for the segment-chirped design exceeds that of single period by a factor of 10, whereas the conversion efficiency is reduced only by a factor of 2.3 .
Subjects
Quasi-phase matching
MgO:LN
temperature bandwidth
Type
thesis
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