Search

We prepared a double-crystal LiTaO3 (LT) electro-optic (EO) Q-switch and investigated its overall Q-switching performances. The LT EO Q-switch is fabricated from two x-cut LT crystals to utilize the maximum effective EO coefficient. The static and dynamic quarter-wave voltage were measured to be 1200 V and 950 V respectively, which are both considerably lower than those of other commercial EO Q-switches. Besides, the LT Q-switch can operate at a wide temperature range with high temperature stability. The dynamic-to-static ratios at sub-freezing temperatures were up to 80 percent of that at room temperature. Furthermore, the piezoelectric ringing in the LT Q-switch was found to be comparable to that of RTP Q-switches, and it had been successfully operated at a repetition rate of 1 kHz with stable Q-switched laser output. The only disadvantage is the low extinction ratio which is mainly caused by the optical inhomogeneity and can be improved by improving the optical quality of LT crystals. The double-crystal LT EO Q-switches are particularly attractive for Q-switched lasers because of their excellent comprehensive performances. [ABSTRACT FROM AUTHOR]

We analyze the transverse electro-optic (EO) effect in an arbitrary direction in LiNbO3 (LN) and LiTaO3 (LT) crystals based on the Fresnel index ellipsoid theory. A set of analytical formulas for calculating the birefringence in any direction in a crystal of the lowest symmetry is first deduced. The maximum magnitudes of the transverse EO effect appear along the directions that are turned out from the optic axis on the angles θm (φ = 30°, 150° or 270°) or 180°− θm (φ = 90°, 210° or 330°), the angles θm of congruent LN and LT crystals are 36° and 59.5°, respectively. For experimental verification, the (yzw)θm cut congruent LN and LT crystals were prepared. The half-wave voltage (HWV) of the (yzw)36° cut LN crystals is half that of the x-cut LN crystals and is only 30% that of the z-cut LN crystals, and the HWV of the (yzw)59.5° cut LT crystals is 7% higher than that of the x-cut LT crystals, the experimental results agree well with the theoretical analysis. The crystals with the optimized cell geometries are more practical because of the low HWV and lower sensitivity of birefringence to temperature. [ABSTRACT FROM AUTHOR]