A downhole laser measurement system useful for evaluating the chemical or elemental composition of geologic formations or formation fluids or interrogating a fiber optic sensor includes a pressure housing, wherein the pressure housing further includes a laser disposed in communication with a laser temperature control chamber; a laser light feedthrough; and an optical sensor array. An associated method of using a laser measurement system in a downhole well bore includes disposing a laser measurement system downhole in a well bore; using the laser to create a laser light, and then outputting the light to an optical sensor array.