Quasi-Phase-Matching Second Harmonic Generation Green Laser in Periodically-Poled MgO:LiNbO3

This thesis is organized into three parts：(a) The theory of quasi-phase-matching (QPM) and second harmonic generation (SHG), (b) The fabrication techniques of periodically poled magnesium-oxide-doped congruent lithium niobate(MgO:LiNbO3), (c) Optical measurement and characteristic analysis of periodically-poled MgO:LiNbO3 laser chips for producing second harmonic generation (SHG) of green laser. irst, the theory of QPM and nonlinear optical generation will be introduced. In the second part, the fabrication technique improvements are based on electric poling method of congruent lithium niobate. This method leads to the realization of periodically poled QPM structures of 0.5 mm thick MgO:LiNbO3 substrates. The smallest periods achieved in this work are (i) 6.75 um for the 1st 2D、(ii) 13.8 um for the 2nd 1D and (iii) 6.9 um for the 1st quasi-1D QPM device. These chips are suitable for producing SHG green laser. Finally, a green laser made of 0.8 mm long periodically poled MgO:CLN are tested by a pulsed 1064 nm laser of 100 MW/cm^2. The device exhibits a broad temperature acceptance width of 30 ℃ and SHG efficiency of 10.6 %, which yield 26.4 mW green at 250 mW 1064 nm pump.