Because this issue journal is dedicated to Gelatin, here we present a few applications of gelatin in the field of optics. Optics is the science that studies the production, propagation, interaction and detection of light. Various materials sensitive to light (photosensitive) are used for detection of light, such as photomultipliers, CCDs, crystals, two dimensional (2D) materials and more. Among the 2D materials, the most popular for several centuries has been gelatin based photographic emulsion, which records spatial distributions of light. More recently (1970), films made of Gelatin with Dichromate (DCG) and dyes have been used. We describe some characteristics and applications of these two photosensitive materials. We also describe examples where gelatin is used as a Relative Humidity (RH) sensor and in the fabrication of optical elements based on gelatin. This article is intended for researchers outside the optics community.

Subject of study. Registration processes of highly effective relief-phase holographic structures on gelatin-containing photosensitive media at high spatial frequencies are studied. Aim of study. The goal is to develop advanced technologies for processing recording media based on the destructive effect of short-wave ultraviolet radiation on gelatin. Method. A significantly shortened time procedure for etching gelatin irradiated with ultraviolet radiation to suppress the influence of surface tension forces smoothing the surface relief of the structure at high spatial frequencies is included while processing photosensitive layers. Water and glacial acetic acid solutions in isopropyl alcohol were used as etchants. Main results. The samples of relief-phase holographic gratings demonstrate high diffraction efficiency in the range of spatial frequencies of 1200−1600mm⁻¹ up to 67% for dichromated gelatin (PFG-04 photographic plates, OJSC Slavich Company) and 42% for silver halide emulsion (PFG-01 photographic plates, OJSC Slavich Company) and have low angular selectivity. High diffraction efficiency values were obtained in the wide range of thicknesses (0.7–26 µm) of the recording media used. Practical significance. The proposed improved methods of processing gelatin-containing photosensitive layers contribute to increasing the range of recorded spatial frequencies during the formation of relief-phase holographic structures, thereby expanding the scope of application of silver halide photoemulsions and dichromated gelatin in holography.

The possibility of creating effective relief holographic gratings with a high spatial frequency of 1500 mm⁻¹ on the layers of dichromated gelatin (DCG) using the destructive effect of short-wave UV radiation on gelatin is shown for the first time.

A new variant of manufacturing high-frequency holographic gratings with a spatial frequency up to 1500 mm^–1 on layers of dichromated gelatin (DCG), in the processing technology of which water procedures are completely excluded, is proposed. The method is based on the use of glacial acetic acid after the photodestruction of layers by exposure to short-wave UV radiation instead of the standard method of processing holographic structures registered by coherent He–Cd laser radiation. In the course of the experiments, relief-phase holographic gratings with high diffraction efficiency up to 64% were obtained, regardless of the thickness of the DCG layers.

The application of two types of alternative action on gelatin in the layers of dichromated gelatin (DCG) was considered: structuring with the use of select

A new variant of manufacturing high-frequency holographic gratings with a spatial frequency up to 1200 mm^–1 on silver halide photographic material for holography PFG-01 is proposed, the processing technology of which is tanning bleaching in bleach containing dichromates and etching in water or in solutions of glacial acetic acid in isopropyl alcohol. The key point is the destructive effect on gelatin of short-wave UV radiation with a wavelength of less than 270 nm. During the experiments, relief-phase holographic gratings with high diffraction efficiency up to a value of 42% were obtained.