Open AccessHarmonically mode-locked Yb:CALGO laser pumped by a single-mode 12 W laser diode
Author(s) -
Sha Wang,
Yanbiao Wang,
Guoying Feng,
Shouhuan Zhou
Publication year - 2018
Publication title -
optics express
Language(s) - Polish
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.001521
Subject(s) - optics , laser , materials science , fiber laser , active laser medium , injection seeder , fabry–pérot interferometer , mode locking , laser diode , laser pumping , laser power scaling , pulse duration , optoelectronics , physics
We present a SESAM mode locked Yb:CALGO laser with a harmonic repetition rate to the 300th order pumped by a single-mode fiber coupled laser diode. By fine tuning the internal angle between the laser beam and the normal axis through the gain medium, at pump power of 1.2 W, an average output power of 132 mW is achieved with a pulse duration of 777.6 fs and a repetition rate of 22.4 GHz. The amplification effect over several tens of roundtrips induced Fabry-Perot filtering of the anti-reflection (AR) coated gain medium is analyzed. The modulation depth increases and the FWHM of a passband Δυ crystal decreases with increasing roundtrip numbers in the laser crystal. The intra-cavity pulse shaping mechanism with a comb filter caused by the amplified etalon effect of the AR coated laser crystal leads to the overall mode spacing equal to the free spectral range of the gain medium other than the laser cavity and results in the high repetition rate running.