Abstract: Low-cost composite infrared windows that are transparent to long wave infrared radiation (8-12 microns) that provide sufficient strength and impact resistance for automotive-type environments, and the like. The windows may be used with night vision systems for automobiles, surveillance imaging systems, and other applications requiring low cost, long wave infrared windows. In one embodiment, the composite infrared window is a sandwich comprised of a polyethylene plastic film bonded with an acrylic adhesive to a relatively thin (0.015-0.040 inch) silicon substrate. The thin silicon substrate is mechanically stiff and low cost, and transmits in the 8-12 micron bandpass. The thin (0.001-0.007 inch) plastic film provides an exterior particle impact absorbing layer sufficient to enable the use of the window in automotive applications.