| Summary: | 碩士 === 國立中央大學 === 光電科學與工程學系 === 102 === Yellow-orange pulsed lasers are required for astronomic observation and medical applications. We have succeed design and manufacture aperiodically poled lithium niobate(APPLN) as EO Bragg Q switching in Nd:YVO4 dual wavelength sum frequency generate Orange-Yellow pulse laser.
In this letter, we design APPLN by aperiodic optical superlattice technique and simulated annealing method. Beam spot size of incident light, aperiodically structure area and other reason effect diffraction efficiency. However, the coupled mode theory in APPLN is complicated, so the theory haven’t been publish.
The beam spot size of the incident light is about 300μm, we design two device. The first device which width is 920μm design for incident light and diffraction light, and the second device which width is 560μm design for incident light only. Both length is 3cm and thickness is 500μm.
We can measure different diffraction efficiency with different incident light position. When the incident light input the device’s middle position of the width dimension, we get the highest diffraction efficiency at the first device. Then we put the first device into laser cavity. Under the optimum cavity-length condition, the highest Orange-Yellow pulse laser peak power is 270W, pulse width is 9ns, obtained at 5.8W of absorption pump power.
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