Mode-locked red-emitting VECSELs

Three years after the first realization [1] of the vertical external-cavity surface-emitting laser (VECSEL), passive mode locking by inserting a semiconductor saturable absorber mirror (SESAM) into the cavity was presented [2]. Besides the advantageous properties in continuous wave operation such as a near-diffraction limited beam profile and the possibility of bandgap engineering, SESAM mode-locked semiconductor disk lasers have shown to produce ultrashort pulses with excellent results in the infrared spectral range. With pulse durations down to 100 fs [3], peak powers of up to 4.35 kW [4] and a maximum average output power of 6.4 W from a semiconductor chip including both the gain and the absorber [5], the performance of these compact pulsed laser systems has rapidly advanced in recent decades [6]. Direct emission of a mode-locked VECSEL in the red spectral range has first been reported in 2013 [7] with 5 ps pulses at a wavelength of 675 nm.