Photoconductor-Thermoplastic Devices For Holographic Nondestructive Testing

Abstract

Although photoconductor-thermoplastic devices have been considered for holographic applications in the past, they suffered from limited recording bandwidth and poor noise characteristics; as a consequence, they were confined to recording holograms of relatively small objects. In this paper techniques for improving the spatial bandwidth to 1500 lines/mm are described. Furthermore, the frost formation mechanism was investigated, and means for suppressing the frost were determined, thereby leading to improved signal-to-noise ratios. These results, together with high exposure sensitivity (50 ergs/cm2) and the improvement in sample fabrication, have led to an operable device which may be incorporated into most holographic nondestructive systems.