The temporal and spectral development of picosecond pulses from a high-power active-passive mode-locked Nd:YAG oscillator-amplifier system1 are described. Spectral measurements with a high-resolution spectrograph are performed simultaneously with temporal measurements using an ultrafast streak camera. Near transform-limited pulses (25 psec, 0.8 cm−1, FWHM) are generated in the early part of the mode-locked pulse train. For pulses selected near the maximum of the pulse train the spectral and temporal widths broaden. As previously reported for mode-locked Nd:glass2–4 and Nd:YAG1,5 lasers, an irregular spectral structure is observed due to self-phase modulation and spectral hole burning.
© 1984 Optical Society of AmericaPDF Article