Mode-locked laser using a saturable absorber in a cavity

Claim 1

A mode-locked laser for generating short pulses of optical energy comprising: (a) a laser operating at a first optical frequency and having an amplifier and a first optical resonator which first optical resonator occupies a first spatial volume, (b) a second optical resonator which occupies a second spatial volume, (c) said first and second spatial volumes consisting, at least in part, of a common spatial volume that is common to both the first and second spatial volumes, (d) a saturable absorber located within the common spatial volume so as to absorb electromagnetic energy at the first optical frequency, emit electromagnetic energy into the second optical resonator by lasing action at a second optical frequency, and be acted upon by the electromagnetic fields in the second optical resonator so as to effectively reduce the recovery time of the saturable absorber, thus allowing the saturable absorber to mode-lock the laser at a range of wavelength where proper mode-locking is not feasible using the saturable absorber in the absence of the second optical resonator, (e) said second optical resonator being resonant at the second optical frequency at which the saturable absorber emits electromagnetic energy by lasing action.