Krausz, F., Spielmann, C., Brabec, T., Wintner, E., & Schmidt, A. (1990). Subpicosecond pulse generation from a Nd:glass laser using a nonlinear external cavity. Optics Letters, 15(13), 737–739. https://doi.org/10.1364/ol.15.000737
An actively mode-locked, continuous-wave Nd:glass laser pumped by a krypton laser at 0.8 microm has been coupled to a nonlinear external resonator. The 20-psec pulses produced by active mode locking are shortened to less than 1 psec with the nonlinear external cavity feedback. Subpicosecond pulse generation has been achieved at a pump power as low as 500 mW.