MECHANISMS OF FORMATION OF HIGH-FREQUENCY RELIEF HOLOGRAPHIC GRATINGS ON DICHROMATED GELATIN EXPOSED TO SHORT-WAVE UV RADIATION
N. M. Ganzherli1, S. N. Gulyaev2, I. A. Maurer1, A. V. Arkhipov2
1Ioffe Institute of Physics and Technology, St. Petersburg, Russia
2St. Petersburg Polytechnic University of Peter the Great, St. Petersburg, Russia
Keywords: структурирование, деструкция, голографические дифракционные решётки, поверхностный рельеф, коротковолновое УФ-излучение, бихромированный желатин, изопропанол, structuring, destruction, holographic diffraction gratings, surface relief, shortwave UV radiation, dichromated gelatin, isopropanol
Abstract
In this paper, we consider two types of alternative treatment of gelatin in layers dichromated gelatin (DCG) layers: structuring using selective light tanning by He-Cd laser light (λ = 440 nm) and destruction by irradiating the layers with short-wave UV radiation (λ < 270 nm). It is shown that UV irradiation of samples plays a decisive role in the formation of high-frequency relief-phase gratings with a diffraction efficiency of more than 50% on DCG layers less than 2 mkm thick. It is noted that the use of traditional methods of treating DCG layers leads to smoothing of the relief due to surface tension forces at high spatial frequencies. In addition, a significant expansion of the region of recorded spatial frequencies (up to 1500 mm-1) for recording relief holographic gratings was achieved by using an advanced method of processing gelatin based on a reduction of water treatment time, and using isopropanol baths for rapid dehydration of the layer
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