DICHROMATED GELATIN REFLECTION GRATINGS INFLUENCE OF SECONDARY GRATINGS

Reflection gratings were recorded in dichromated gelatin by using a no n-symmetrical recording geometry. In addition to the primary grating, secondary gratings were also formed, as is generally known. It is foun d that the secondary gratings assist the structure stability during de velopment in the exposure energy range (50-100)mJ cm-2. The structure containing these secondary gratings is more rigid than those without a nd the reflection grating period is more stable during the development process in this exposure energy range, which is most suitable for the transmission grating formation. Secondary gratings also cause unwante d noise, but the noise level is low and the improved stability outweig hs the extra noise.