From Laboratory to CubeSat - Room Temperature Absolute Bolometers for Laser Power Standards, Solar Spectral Irradiance, and Total Solar Irradiance

Planar micromachined silicon bolometers with carbon nanotube absorbers provide high accuracy, compact, and rugged radiation detection. We are building on the success of our silicon micromachined planar detectors operating at cryogenic temperatures1 to develop similar electrical substitution bolometers that operate at room temperatures. These bolometers currently have applications as both laboratory standards for laser optical power and for solar irradiance monitors in space. Room temperature operation of these detectors for the above applications presents a different set of technical challenges from similar cryogenic detectors. The materials used for temperature measurement are different and inherently noisier, time constants are longer, and practical applications demand a greater dynamic range in power and a larger detector size. We will describe the design and performance of three room temperature devices. The first is a laboratory based room temperature device for precision CW optical power measurements (Next-Gen C). This standard operates from 0.4 to 2 um and over a dynamic range of 50 uW to 100 mW. The second is a bolometer designed for solar spectral irradiance measurement that will be part of the Compact Spectral Irradiance Monitor (CSIM) CubeSat mission, scheduled for launch in the Fall of 2018. The third is a bolometer under development for total solar irradiance measurement as part of the Compact Total Irradiance Monitor (CTIM) instrument development