Abstract

The Ti:sapphire laser has already proved itself to be the laser of choice for near infrared cw laser applications. In a standard folded-astigmatically compensated cavity, however, the pump power threshold is as high as 4 W making a medium-to-large frame argon or lamp-pumped dye laser necessary as the pumping source. To make the Ti:sapphire laser more reliable and accessible for both laboratory and commercial applications, it will be necessary to eliminate the need for such a large pumping laser by reducing the threshold pumping power. Astigmatically compensated laser cavities allow one to balance the intracavity astigmatism by the folded focusing optics, however, the spot in the focal region can be quite large and astigmatic. To reduce the threshold power the focal spot size needs to be reduced as much as possible. For this reason we designed a linear cavity which uses intracavity lenses to focus the light and an antireflection coated Ti:sapphire rod which is slightly wedged. In this manner the spot size is reduced significantly since all the astigmatism generating components have been eliminated. The cavity has been demonstrated and the pumping threshold power was decreased by a factor of 5–800 mW compared to the folded cavity design.

© 1989 Optical Society of America