We propose to demonstrate the feasibility of an infrared (IR) beam combiner based on variable electrochromic devices. The optical properties of an electrochromic material are dependent on an applied voltage. Therefore the use of electrochromic materials will allow for significant variation of the combining mirrors' reflection and transmission properties without necessitating the swapping of components. The optical properties of six materials will be evaluated in the IR for use in these devices including: electrochromic layers (crystalline WO3, ZnO), an electrolyte (Ta2O5), and storage layers (amorphous WO3, NiO, V2O5). The infrared spectra of each material at varying levels of intercalation will be modeled to simulate optimized electrochromic behavior for IR beam combiners. Deposition of complete electrochromic devices for IR evaluation and validation of simulations will be completed. Finally quantitative evaluation of device performance at reduced temperatures through electrical impedance spectroscopy will be performed to evaluate the switching time of a device in a cryo-vacuum environment
