Compact mid-IR laser

A mid-IR (MIR) laser device comprising:

• a quantum cascade laser that generates light output;
• a switch electrically connected to the quantum cascade laser and operative to turn the quantum cascade laser on and to turn the quantum cascade laser off in a pulsing fashion;
• an optical lens that collimates the light output from the quantum cascade laser, the optical lens having a numerical aperture that is greater than approximately 0.6, a diameter of less than approximately 5 millimeters, and a focal length of less than approximately 5 millimeters, and the optical lens being made of a material selected from the group consisting of Ge, ZnSe, ZnS Si, CaF, BaF, and chalcogenide glass;
• a thermo electric cooling (TEC) device, the TEC device having a top surface;
• a monolithic heat spreader secured to the TEC device, the heat spreader retaining the quantum cascade laser and the optical lens, the heat spreader having a thermal conductivity of at least approximately 220 W/mK, the heat spreader serving to distribute heat to the TEC device from the quantum cascade laser and also serving as an optical platform to fixedly position the quantum cascade laser and the optical lens relative to one another, the heat spreader including a bottom surface that is mounted to the top surface of the TEC device, and wherein the bottom surface of the heat spreader is approximately the same size as the top surface of the TEC device so that heat is distributed over the entire top surface of the TEC device;
• a high thermal conductivity sub-mount positioned between the quantum cascade laser and the heat spreader, the sub-mount having a thermal conductivity of between approximately 500-2000 W/mK;
• and
• a housing that encloses the quantum cascade laser, the optical lens, the TEC device, the switch, the sub-mount, and the heat spreader;
• the housing having dimensions of less than approximately 20 centimeters by 20 centimeters by 20 centimeters;
• wherein the operation of the quantum cascade laser generates at least approximately ten watts of heat output, and wherein the TEC device can control the temperature of the quantum cascade laser to be approximately room temperature.

A method for generating light output, the method comprising the steps of:

• directing power to a quantum cascade laser to generate light output;
• collimating the light output from the quantum cascade laser with an optical lens, the optical lens having a numerical aperture that is greater than approximately 0.6, a diameter of less than approximately 5 millimeters, and a focal length of less than approximately 5 millimeters, and the optical lens being made of a material selected from the group consisting of Ge, ZnSe, ZnS Si, CaF, BaF, and chalcogenide glass;
• removing heat from the quantum cascade laser with a thermo electric cooling (TEC) device;
• and
• retaining the quantum cascade laser and the optical lens with a monolithic heat spreader that also serves as an optical platform to fixedly position the quantum cascade laser and the optical lens relative to one another, the heat spreader being secured to the TEC device, the heat spreader having a thermal conductivity of at least approximately 220 W/mK.