The invention relates to an intermediate
infrared femtosecond mode-locked
laser which comprises a collimating mirror, a focusing mirror, an input spherical surface mirror, a
laser medium and a spherical surface high-reflection mirror which are sequentially arranged along a direction of a pumping
light beam outputted by a
laser diode, wherein lasers in a five-mirror
laser resonance cavity formed by the input spherical surface mirror, the spherical surface high-reflection mirror, the spherical surface high-reflection focusing mirror, an output
coupling mirror and a
graphene mode-locking element is reflected onto the high-reflection focusing mirror through the input spherical surface mirror, is focused on the
graphene mode-locking element, returns back along the original path by sequentially passing through the spherical surface high-reflection focusing mirror, the input spherical surface mirror, a laser
crystal and the spherical surface high-reflection mirror, is deflected and reflected to a
dispersion compensation prism pair by the spherical surface high-reflection mirror, and is output from the output
coupling mirror through a slit. According to the intermediate
infrared femtosecond mode-locked laser,
graphene growing by adopting a CVD (
Chemical Vapor Deposition) method is transferred to a laser
wavelength high-reflection mirror, and is protected by using
inert gas, and thus stable mode-locked laser pulse output is realized in an intermediate
infrared band. The intermediate infrared
femtosecond mode-locked laser has the advantages of being simple in regulation, low in manufacture cost, and easy to realize single layer (little non-saturated loss).