Fig. 1. Schematic of experimental setup.

Fig. 2. FH output power by a single-pass frequency doubling configuration with KBBF-PCD. The filled circles are experimental data, and the curve is best fit with P_out = E_NLP_in², giving E_NL = 0.06.

Fig. 3. Long-term measurement of the generated FH power at an incident UV power of 400 mW.

Fig. 4. The output signal of lock-in amplifier depends on the optical delay of the fundamental light.

Fig. 5. The 5ω signal measured by changing parameters. (a) The 5ω signal plotted against the power of fundamental light. (b) The 5ω signal versus the crystal-angle.