Fig. 1. Schematic of walk-off angle compensation

Fig. 2. Schematic of principal axis coordinate system before and after crystal rotation of 180° along optical axis

Fig. 3. Schematic of experimental setup

Fig. 4. Harmonic wave pulse energy versus temperature when LBO crystal used for compensating equivalent phase mismatch

Fig. 5. Harmonic wave pulse energy versus temperature when air dispersion used for compensating equivalent phase mismatch