AbstractWe report on increasing the pulse length and repetition rate of p-type germanium lasers through miniaturization, increased electric field uniformity, and improved cooling. We have recently demonstrated that it is possible to improve the electric field uniformity necessary for an efficient laser and at the same time decrease the electrical input power by using a geometry with d/L>>1, where d is the distance between electrical contacts and L is the length in the direction of the Hall field. In order to achieve good heat sinking along with a large d/L ratio, we have developed a new, planar contact geometry. Attaching an undoped, high-resistivity, single-crystal Si heat sink to the base of the Ge planar contact laser increases the duty cycle by a factor of 5.5. In order to further decrease the input power by decreasing the volume of laser crystals in the planar contact geometry, we show as a proof-of-concept the use of polished strontium titanate single crystals as electrically insulating far-infrared mirrors based on restrahl band reflection. The physical phenomena underlying these improvements in this novel geometry will be discussed.
