Новий високотривкий матеріал для інтерференційного покриття інфрачервоного діапазону спектру

Abstract

IR interference optics are currently widely used in night vision devices in aviation, in particular, helicopters and unmanned aerial vehicles (UAVs) and homing systems in long-range missiles, etc. One of the requirements for optical elements of systems operating in the near infrared region of the spectrum (1–6 microns) is the requirement to transmit radiation in the working region of the spectrum and block radiation from adjacent non-working spectral regions. Such systems consist of single- or multi-layer thin-film coatings on substrates transparent in the IR range of the spectrum, for example, silicon, germanium, indium antimonide. In this case, we are talking about cut-off optical filters that block visible or short-wave (up to 1 microns) IR radiation and at the same time transmit IR radiation in the range of 1–6 microns. Such systems are effective for use in optics («IR flashlight») and masking hot gas emissions from engine nozzles.

The article shows the importance and relevance of using the germanium – germanium dioxide – boron oxide composite for depositing thin-film coatings of germanium monoxide by thermal (resistive version) evaporation in vacuum and condensation on substrates made of various materials. To stabilize the state of germanium (II), the introduction of boron oxide additive has been proposed and justified. A mixture of germanium with germanium dioxide and boric acid is first subjected to high-temperature treatment. Thin-film coatings obtained from the specified composite have high mechanical strength and climatic stability, are transparent in a wide spectral range – from 0,8 to 11 microns and have a refractive index of about 2,2 and are practically indistinguishable from the germanium monoxide – boron oxide composite. The use of the composite developed in the work in real optical elements (optical element of a photodetector, cut-off filter) showed its prospects as a highly durable material for interference optics in the infrared range of the spectrum.

A new design of a cut-off optical filter using a material with a low refractive index based on germanium monoxide stabilized by the addition of boron oxide has been proposed. The filter is distinguished by high technological and operational parameters and durability during storage. Its prospects for use in aircraft to increase their survivability have been shown.