Tunable single frequency MECSEL for Ytterbium cooling (Invited Paper)

We present an intra-cavity frequency doubled membrane external cavity surface emitting laser (MECSEL) at 556nm with >20GHz mode-hop free tuning and >3 W of single transverse mode output power with 20kHz line width. The laser is operated with closed loop dither optimization to prevent mode-hop events during operation and tuning of the center wavelength. The optically pumped MECSEL chip was analyzed with a Shack-Hartmann-Sensor to characterize pump-induced higher order spherical aberrations. These measured aberrations are compared to finite-element model results for the chip. We show that temperature-dependent amplified spontaneous and resonating emission must be considered in the analysis to achieve sufficient agreement with the experimental results. The dynamic response of the temperature profile in the chip upon modulation of the pump power was derived from the model and compared to the emission phase response of the laser.