Study of Broadband Quasi-Phase-Matching Nonlinear Process for Green and Blue Generation
Date Issued
2010
Date
2010
Author(s)
Wen, Chien-Su
Abstract
The research topics of this thesis focus on quasi-phase-matching (QPM) frequency conversion using periodically poled lithium tentalate (PPLT) and periodically poled MgO-doped lithium niobate (PPMgO:LN). This thesis is mainly organized into two parts: (a) Structure design of PPMgO:LN with broadbandly accepted temperature bandwidth for second harmonic generation (SHG) and its experiment to verify the SHG conversion efficiency and the temperature bandwidth. (b) Design of PPLT for singly resonant optical parametric oscillator (SROPO) and using green pump laser for blue and white light generation.
For the QPM SHG experiment with single pass configuration, 5mm long PPMgO:LN with ten QPM periodicities was pumped by a Nd:YVO4 Q-switched 1064nm laser. The accepted temperature bandwidth was found to be 49°C, and the conversion efficiency exceeded 20%. Compared with a 5mm PPMgO:CLN with single QPM periodicity, the accepted temperature bandwidth increases from 5.?°C to 49°C and the maximum conversion efficiency decreases from 6?% to 27%.
For the up-conversion blue generation, with the design of multi-QPM periodicities for the cascaded OPO-SHG process, the slope efficiency for the 465nm blue generation, as pumped by a pulsed green laser, reacheed 16%. The linewidth of 465nm blue was broadened to be 0.78nm. By changing the duty cycle of the poling area in PPCLT, the slope efficiency of up-conversion 435nm blue generation increased to 21%.
For the white generation experiment, we used a 25mm long PPCLT where OPO-SHG cascaeded process generates blue and OPO generates red. When the power of green pump reachesd 370mW, we observed simultaneous generation of 465nm blue laser with 25mW power and 630mW with 45mW. If proper power of residual 532nm green laser was selected, then white laser with 100mW power and chromaticity coordinate located in (0.3333, 0.3333) could be realized.
Subjects
quasi-phase matching
optical parametric oscillator
white laser
Type
thesis
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