Fig. 1. Experimental setup of NCPM 5th HG of a 1053 nm laser. Photos of the thermostat for the 4th HG and 5th HG crystals are also shown in the figure.

Fig. 2. Measured (red squares) and calculated (black curve) temperature tuning characteristics for NCPM 5th HG of the 1053 nm laser.

Fig. 3. Measured angular tuning curves at different working temperatures for 5th HG of the 1053 nm laser.

Fig. 4. (a) Fifth-harmonic efficiency and (c) energy balance measured as a function of input pulse energy and intensity. The near-field pattern of the output 5ω radiation is also shown in inset figure (b).

Fig. 5. Phase-matching factor sinc2(ΔkL/2) as a function of angle and temperature.

Fig. 6. Simulated temperature distributions of a 120mm×120mm×5mm ADP crystal in (a) the traditional scheme and (b) the focusing design. The central temperature is set to be −75.1°C. The color bars indicate the temperature deviation.

Fig. 7. 5th HG efficiency optimization with the focal length of the focusing lens for the upgraded focusing design.

Fig. 8. 5ω near-field distribution (a), (c) before and (b), (d) after compensation. Inset figures (a) and (b) represent the situation of the traditional scheme, figures (c) and (d) represent the situation of the upgraded scheme, and the curves are the corresponding 1D profiles.

Fig. 9. Influence of beam center deviation along the e direction on 5th HG conversion efficiency (curves) and 5ω near-field distribution (insets). The black curve along with figures (a), (b), and (c) represents the situation of the traditional scheme, and the red curve along with figures (d), (e), and (f) represents the situation of the focusing design.