We have designed a microfabricated planar absolute radiometer based on a vertically aligned carbon nanotube (VACNT) absorber and an electrical power substitution method. The radiometer is designed to operate at room temperature and to be capable of measuring laser powers up to 300 mW from 300 nm to 2300 nm with an expected expanded uncertainty of 0.06% (k = 2). The electrical power substitution capability makes the radiometer absolute and traceable to the international system (SI) of units. The new bolometer is currently under construction and will replace NIST's 50 year old detector standard for free-space CW laser power measurements. We also study the possibility of reducing background temperature sensitivity by optimizing the spectral selectivity of the VACNT forest with a photonic crystal structure.
Counter to conventional methods of measuring laser optical power, radiation pressure-based power meters operate by reflection rather than absorption. This provides an opportunity for in situ, non-destructive total beam power measurement. Compact radiation pressure power meters designed to operate between a few tens and a few thousands of watts consist of a planar millimeter-scale spring-electrode-mirror component that deflects under radiation pressure from an incident beam. Spring constant, resonant frequency, and quality factor of microfabricated springs as well as coatinginduced straining of the spring are the focus of this manuscript. We compare finite element models of the mechanical component with various measurements to inform future designs.