Spray Cooling Of High-power Semiconductor Laser Diodes

THE CURRENT DEVELOPMENT OF HIGH PERFORMANCE LASER DIODES TO BE USED IN DEFENSE, SUPER COMPUTERS, TELECOMMUNICATIONS, AND MEDICINE HAS INTRODUCED A NEED FOR A RADICAL CHANGE IN THE APPROACH OF LASER DIODE/OPTICS THERMAL MANAGEMENT. IN LASER DIODE ARRAYS, INTEGRATED CIRCUITS MOUNTED TOGETHER ON A SINGLE SUBSTRATE TO FORM ONE LEVEL PACKAGE ALLOW HIGHER LASER INTENSITIES, VARIED FREQUENCIES AT ENORMOUS SIZE, AND WEIGHT SAVINGS. HOWEVER, WITH THE DENSER PACKAGING AND HIGHER INTENSITIES AND CURRENTS IS INTRODUCED A HIGHER HEAT DISSIPATION. UNDER CONDITIONS OF HIGH-HEAT-FLUX THE TEMPERATURES AND THE THERMAL GRADIENTS CAN BECOME CONSIDERABLE. THIS PROPOSED EFFORT WILL PROVIDE A NOVEL TECHNOLOGY FOR COOLING LASER DIODES DIRECTLY IN THE REGION OF HEAT GENERATION BY SPRAY (DROPLET IMPINGEMENT) COOLING THE BARE DEVICE SURFACE DIRECTLY, (AS OPPOSED TO GLUING A HEAT SINK AND COOLING THE HEAT SINK EXTENDED SURFACES), WITH AN ELECTRICALLY DIELECTRIC COOLANT. BY COATING THE DIODE WITH A LAYER OF THERMALLY CONDUCTIVE, STRUCTURALLY INVINCIBLE, AND ELECTRICALLY DIELECTRIC DIAMOND FILM, THE LASER DIODE ARRAYS CAN BE CONFIGURED IN SINGLE AND MULTILAYER CONFUFURATIONS AND CAN EVEN BE COOLED WITH WATER. A HIGH-HEAT-FLUX LASER DIODE WILL BE TESTED TO DETERMINE THE FEASIBILITY AND ENHANCEMENT IN PERFORMANCE OF SPRAY COOLING.