In-band pumped low thermal effect Yb:YCOB self-frequency-doubled yellow laser

A 570 nm laser was successfully achieved using a Yb:YCa4O(BO3)3 crystal with a 1020 nm in-band pump. The measured RMS of the laser power fluctuation over a period of 90 minutes was only 3.76%, and the measured values for the beam quality factor are Mx2 = 1.46 and My2 = 1.62. This may be due to the fact that in-band pumping at 1020 nm significantly reduces the temperature gradient within the crystal during end-face pumping, which effectively mitigates the significant thermal effect during the pumping process and achieves good mode matching.