Abstract

Interferometric autocorrelation widths as low as 30.4 fs FWHM and average outputs from 0.5 W to 2 W are observed at ~800 nm. Deconvolution of pulse duration is accomplished by Fourier transforming the measured pulse spectrum (FWHM = 35 nm) and numerically autocorrelating the result. The measured autocorrelation agrees with this transform limit, which corresponds to a 20.0 fs FWHM pulse. A ray tracing analysis of cavity dispersion is used to predict the optimum placement, orientation, design, and composition of intracavity prisms that minimize cubic phase error. Prisms composed of Schott glass LaK31 are used and result in 60% less cubic phase error than SF10 and 30% less than LaFN28. High output powers are achieved by increasing the pump power (10 W to 18 W) and simultaneously modifying intracavity focusing to compensate for increased thermal and Kerr lensing in the laser rod. Mode-locked operation is initiated, and cw breakthrough is suppressed by a high modulation depth (≥20%), regeneratively driven, non-resonant, intracavity AOM. At highest powers, streak camera measurements indicate the presence of stable, closely spaced (~10 ps), double pulsing in the cavity. Plans for use with an existing 100 mJ Ti:sapphire amplifier will also be discussed.

© 1992 Optical Society of America