Study on the Stability of the Latent Image in the MBDCG Hologram

ABSTRACT The stability of the latent image recorded in TMG-MBDCG was studied by means of investigating on the real-timediffraction efficiency. We found that the latent image will decline under low exposure, and such phenomenon can bereduced by heating . The mechanism of such decline is discussed in this paper also.keywords: DCG, MBDCG, latent image, hologram, real-time diffraction efficiency 1. INTRODUCTION Dichromated gelatin ( DCG ) is one of the best holographic recording materials because of its high diffiractionefficiency and low noise. A major shortcoming of this recording material is that it is essentially insensitive to light ofwavelengths much longer than 514 nm . The spectral sensitivity of DCG can be extended to red light wavelengths byadding methylene blue 2 5 The sensitivity of such recording material ( MBDCG ) at633 nm , however , is less thanone-tenth of that of DCG exposed at 488 mm. In order to increase the sensitivity of MBDCG , a lot of trying. has beendone 68 Adding some electron donor in MBDCG is one of the methods .