Affiliation:
1. Adam Mickiewicz University
Abstract
Mode-locking in Cr:ZnS/Se lasers typically rely on Kerr-lensing (KLM)
or a semiconductor saturable absorber mirror (SESAM). The former
allows generation of shorter pulses, but, unlike the latter, does not
support self-starting mode-locking. Here, we combine the advantages of
these two techniques and demonstrate the SESAM-assisted KLM Cr:ZnS
laser. Our self-starting oscillator generates up to 1 W of average
power with 54 fs pulses at a central wavelength of 2360 nm. We
identify a general limitation for further pulse shortening in SESAM
mode-locked Cr:ZnS/Se lasers, which is related to the finite operation
bandwidth of the semiconductor absorbers. In our experiment, we fully
exploit the potential of commercially available GaSb SESAMs and fill
their entire reflection bands. Furthermore, we compare the performance
of a SESAM-assisted KLM laser with a pure KLM oscillator producing
broadband, yet not self-starting, 33 fs pulses with 780 mW power. We
also show that the choice of saturable absorbers has a negligible
impact on the laser intensity noise, which is exceptionally low with
sub-0.005% integrated noise.
Funder
Narodowa Agencja Wymiany
Akademickiej
Narodowe Centrum Nauki
Max-Planck-Gesellschaft