Infrared optical modulators for missile testing

✍ Scribed by Mark A Richardson; John A Coath

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 285 KB
• Volume: 30
• Category: Article
• ISSN: 0030-3992
• DOI: 10.1016/s0030-3992(98)00035-8

✦ Synopsis

The continued proliferation of imaging infrared (I 2 R) missile systems has created the need for fully representative infrared scene generators. In order to test these I 2 R systems correctly a very large dynamic range is required of the scene generator. This cannot easily be produced by the standard approach of an array of suspended resistor heater elements. This paper therefore describes the fabrication of infrared optical modulators for use in high dynamic range and high frame rate scene generation. Modulation is produced by the heating of a variable re¯ectivity coating. This is achieved by coating a suitable substrate with a thin ®lm of vanadium dioxide (VO 2 ) via a reactive sputtering process. VO 2 undergoes a semiconductor to metal phase transition at approximately 688C and the associated change in re¯ectivity is exploited to create the modulator. The correct stoichiometry of the thin ®lm of VO 2 is critical in producing high frame rate devices. Both transmissive and re¯ective modulators are described.