Fig. 1. Schematic diagram of Yb³⁺-ion electron energy level transition

Fig. 2. Yb∶YCOB crystal transmittance spectrum

Fig. 3. Mode matching efficiency versus input power under different pump modes

Fig. 4. Experimental device of 1020 nm pumped Yb∶YCOB crystal yellow laser self-frequency doubling laser

Fig. 5. Experimental device of 976 nm pumped Yb∶YCOB crystal yellow laser self-frequency doubling laser

Fig. 6. CCD detection of yellow laser spot map emitted from 1020 nm laser pumped Yb∶YCOB self-frequency doubling crystal. (a) Spot shape; (b) spot distribution

Fig. 7. CCD detection of yellow laser spot map emitted from 976 nm laser pumped Yb‍∶YCOB self-frequency doubling crystal. (a) Spot shape when input power is same as 976 nm LD pump; (b) spot distribution when input power is same as 976 nm LD pump; (c) spot shape when output power is same as 976 nm LD pump; (d) spot distribution when output power is same as 976 nm LD pump

Fig. 8. Yellow laser spectrum of Yb∶YCOB self-frequency doubling crystal pumped by 1020 nm laser

Fig. 9. Yellow laser spectrum of Yb∶YCOB self-frequency doubling crystal pumped by 976 nm LD