Chinese Journal of Lasers, Vol. 44, Issue 5, 501008 (2017)

Femtosecond Thin-Disk Regenerative Amplifier Under Burst Operation Mode

Abstract

In order to obtain femtosecond laser pulses with high repetition rate, a burst operation mode is introduced into femtosecond thin-disk regenerative amplification system. The cavity length of the regenerative amplifier is designed as 9.3 m, so that the laser pulse which is close to the diffraction limit can be generated. The repetition rate of the laser pulse is 5 times of the electro-optic modulation frequency. Under the condition that the electro-optic modulation frequency is 5 kHz and the absorbed pump power is 98 W, hyperbolic secant pulses with maximum output power of 10.7 W, spectrum full-width-half-maximum (FWHM) of 1.18 nm, pulse width of 777 fs are obtained. The optical-optical conversion efficiency of the regenerative amplifier increases with the increasing of the electro-optic modulation frequency, and the optical-optical conversion efficiency increases from 12.4% at 0.5 kHz to 25.3% at 5 kHz. The laser output stability improves in the range of 18-20 ℃ with the decreasing of chiller temperature, and the output power root-mean-square of the laser system changes from 0.93% at 20 ℃ to 0.52% at 18 ℃. These results have great values for designing the stable femtosecond laser system with high repetition rate and high power.

keywords

• burst operation mode
• diode pumped laser
• laser optics
• regenerative amplifier
• thin-disk laser