Visible/long-wave infrared dichroic beamsplitter

Visible/long-wave infrared (LWIR) beamsplitter optical elements are designed, fabricated, and tested to enable implementation of a single common-aperture dual-spectral-mode imaging sensor system. The coating design is compatible with both germanium and low-cost electronic-grade silicon wafer substrates. Multispectral transmission and reflection efficiencies averaging over 90% are measured over both the visible to near IR (NIR) and the LWIR spectral regions, in agreement with theoretical models. The coating design uses commercial-off-the-shelf (COTS) coating materials known to exhibit excellent mechanical and environmental stability for performance reliability and extended operational lifetime. (c) 2005 Society of Photo-Optical Instrumentation Engineers.