Noncorrosive microcoolers with matched CTE
At Photonics West 2005 a new technology was described for building a new, non corrosive micro cooling heat sink for diode lasers made of stainless steel with the procedure of three dimensional laser melting. Due to the thermal conductivity, which is 20 times worse than the conductivity of copper, first test leads to the result, that it is not possible to compensate the worst thermal conductivity by an optimized inner structure, regarding wall thicknesses and flow rate. So the solution was searching a different material, with a better thermal conductivity to achieve a thermal over all resistance that is usable for the cooling of high power laser diodes. Searching that material leads to a special nickel alloy in the field of nuclear industry. The new generation of micro coolers are named TEX series. All TEX Series coolers were made out of a special nickel alloy, specially developed as a corrosion protection material. Therefore, the TEX coolers have excellent corrosion resistance. In addition, due to the manner and way of using three dimensional laser melting, the surface of the inner structure was hardened. The hardening HV1 is 380, so that there is no danger regarding erosion or a combination of erosion and corrosion. Metallization and soldering the semi conductor also had been tested. The commonly used structure with Nickel and Gold is possible as well as the metallization only with gold. With both variations the semi conductor can be soldered and the connection to the cooler surface is very strong.