Optical shutters for a compact femtosecond Yb:KYW laser

• Published in: Laser physics 2020-02, Vol.30 (2), p.25001
• Main Authors: Rubtsova, N N, Kovalyov, A A, Ledovskikh, D V, Preobrazhenskii, V V, Putyato, M A, Semyagin, B R, Kuznetsov, S A, Pivtsov, V S, Semenko, A V
• Format: Article
• Language: English
• Subjects: design of specific laser systems; mode locking; nondestructive optical testing; optical properties of nanoscale materials; quantum wells
• ISSN: 1054-660X; 1555-6611
• DOI: 10.1088/1555-6611/ab5946

A stable passive mode-locking regime for a Yb3+ :KY(WO4)2 laser with optical pumping by a continuous diode laser was obtained using two types of optical shutter with a saturable absorber based on coupled GaAs/In0.25Ga0.75As/GaAs quantum wells. The shutters differed in their reflecting part: the first type was a semiconductor mirror and the second type was a dielectric one. The typical parameters of the mode-locking regime were as follows: a pulse duration of about 200 fs for both types of shutter, an average power of 2.54 W for the all-semiconductor shutter (SESAM) and 0.92 W for the dielectric mirror with a saturable absorber (DSAM). The efficiency relative to the incident pump power was 57% for the SESAM and 19% for the DSAM. The maximum pulse repetition rate was 982 MHz. The measured recovery time was about 2 ps for both saturable absorbers. The mirror damage threshold estimate for the SESAM was at least 8.87 mJ cm−2.