Accession Number:

ADA231086

Title:

New Materials and New Techniques for Imaging of Long Wavelength IR radiation

Descriptive Note:

Final rept. 1 Oct 1987-31 Mar 1990

Corporate Author:

PENNSYLVANIA STATE UNIV STATE COLLEGE MATERIALS RESEARCH LAB

Personal Author(s):

Report Date:

1990-11-02

Pagination or Media Count:

69.0

Abstract:

Work on this program was directed towards the preliminary verification of the possibility of a completely new type of long wavelength infra-red imaging system. This study proposed to explore the change in polarized reflectance from the pyro-optic surface making use of the exceptional sensitivity of the newer ellipsometric techniques for reflectance studies. Cardinal advantages for the pyro-optic reflectance method are Thermally sensitive film need only be thick enough to support the evanescent wave on reflection, so that pixel volume mass can be exceedingly small. Films can be mounted upon a critically dehydrated gel substrate which is transparent to visible light but affords near perfect thermal isolation. There is no need for contacts to individual pixel elements as in the pyroelectric imagers. Calculations show that for a film 0.1 micron meter thick, mounted on a silica gel substrate the thermal efficiency is such that if the thermometric sensitivity of the film is sufficient to detect a temperature change of 1mK then for a system with f1 optics this could correspond to a temperature difference in the object plane of 0.1K. The studies on this program were in two parts, the first objective was to verify the high values of temperature derivative of refractive index which has been reported in bismuth vanadate BiVO4, molybdenum MoS2 and antimony sulphur iodide SbSI. The second objective was to design and build a compact thermoelectric heater cooler which could be used to impart a known small AC temperature change to explore the detectivity limit for a pyro-optic reflectance system.

Subject Categories:

  • Infrared Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE