Fig. 1. Schematic diagram of cascaded frequency-doubling laser generation and UV output powers^[41]

Fig. 2. (a) DeltaConcept: Frequency doubling cavity with Δ- configuration; (b) Movement direction of the prism ^[44]

Fig. 3. (a) Experimental setup; (b) Output power vs input power ^[47]

Fig. 4. (a) Experimental setup; (b) Output power of 266 nm laser; (c) Power stability curve

Fig. 5. (a) Schematic diagram of PDH frequency-locking principle ^[49]; (b) Modulation sideband; (c) Error signal of PDH frequency stabilization^[50]

Fig. 6. (a) Experimental setup of the DUV laser system; (b) 532 nm laser output power and frequency doubling conversion efficiency; (c) 266 nm laser output power and frequency quadrupling efficiency ^[55]