Abstract

There is much interest in femtosecond spectroscopy of semiconductor heterostrucures in materials which have a bandgap wavelength near 1.5µm. For a long time, the time resolution of these studies was limited to several picoseconds which is characteristic of the synchronously pumped F-center lasers. Recently, stable sources of 100 fsec pulses around 1.5µm have been developed, using F-center lasers. The soliton laser [1] and subsequently the additive-pulse-modelocked laser (APM) [2,3] are capable of producing 100-200 fsec pulses routinely with up to 1.5 nJ of energy. However, for some applications, higher pulse energies are needed. In particular, femtosecond continuum generation requires pulse energies of a few microjoules. The NaCl F-center system [4] is particularly attractive as a gain medium for femtosecond pulses because of its large gain bandwidth (200 nm), and its relatively long gain storage lifetime (200 nsec). We report here, die amplification of picosecond pulses to energies of of .24 µJ using F-centers in NaCl. Pulse energies of several microjoules should be easily obtainable in the future.

© 1990 Optical Society of America