Direct Generation Diode-Pumped Mid-IR Laser

Efficient sources operating in the mid-IR region are required for applications such as laser countermeasures and remote sensing. Available mid-IR lasers suited to these applications employ nonlinear frequency conversion techniques; an approach which is inefficient and requires high intensities. Sources based upon direct generation currently are limited to wavelengths below 3 micrometers. Direct generation of 3-5 micrometer radiation using rare-earth ion activated solid-state materials represents a desirable and efficient configuration for laser sources in the mid-IR. In our pursuit of this goal, we have identified two rare-earth doped solid-state materials with the potential for CW operation in the 3-5 micrometer regime. In each case, efficient diode pumped room temperature operation is obtained through the use of a sensitizer-activator pair. The Phase I program consists of a detailed spectroscopic study of the key material parameters which are critical for mid-IR laser operation. Based upon the results of this investigation, a power scalable CW, solid-state, diode-pumped, room temperature laser will be demonstrated. Additionally, design studies will be conducted for scaling to the 2 W average power level.