Abstract

Coherent laser radar systems operating in the 2 μm spectral range have recently been demonstrated to work very well. For example, horizontal wind measurements to > 20 km and hard-target measurements to ranges of about 150 km have been shown with our fielded system. To date 2 μm systems have been based around flashlamp pumped Cr,Tm,Ho:YAG. In this material Cr is used to absorb pump light, energy is transferred to Tm, following which cross-relaxation and energy transfer populates the lasant Ho ions. In recent years it has also been demonstrated that Tm can be pumped by laser diodes and that direct laser action in Tm near 2.0 μm can be extremely efficient.

© 1991 Optical Society of America