PROSPECTS AND TRENDS IN THE DEVELOPMENT OF DEVICES AND METHODS BASED ON THE PHENOMENON OF SURFACE PLASMON RESONANCE IN THE INFRARED RANGE (REVIEW)

Abstract

On the phenomenon of surface plasmon resonance (SPR) and its use for the study of gaseous and liquid substances, more and more papers are published in professional journals. These studies are used in clinical diagnostics, food industry, environmental monitoring. The advantages of SPR sensors include quick results, a small amount of analyte, the possibility of real-time measurement of such reactions as antigen-antibody, protein-protein, enzyme-substrate or inhibitor, protein-DNA, receptor-drug, protein-polysaccharide , virus protein and reactions of external stimulation of a living cell. The high sensitivity of the method is due to the properties of its resonant nature of plasmon-polariton oscillation. SPR devices are used in laboratory conditions and there is a potential possibility of further reduction of overall dimensions for use in field conditions. The use of SPR in the IR region of the spectrum has a number of advantages, namely: the laser light penetrates deeper into the sample, it becomes possible to study substances that are not transparent in the visible region, but transparent in the infrared, which allows working with larger research objects, provides a narrower characteristic of the SPR, which allows to more accurately determine the angle of the minimum of the SPR, and also requires the application of a thinner layer of gold on the glass chip, which reduces the cost of the analysis. The review analyzed literary sources and determined prospects for the development of devices and methods based on IR SPR, considered prospective materials of the sensitive element and prisms of the total internal reflection device according to the Kretchman scheme. It was determined that, in addition to precious metals (gold and silver), conductive metal oxides ITO, ZnO, CdO:Dy have the prospect of being used as materials for manufacturing the sensitive element of the sensor. Their compliance with the requirements for materials for maintaining the SPR was analyzed. It is shown that CdO:Dy has the greatest potential due to sufficient mobility and density of charge carriers. But in practice, the most common use is gold and silver, for which it is necessary to determine the optimal thicknesses for the IR range of SPR. Total internal reflection prisms (hereafter prisms) in SPR devices according to the Kretchman scheme are usually made of glass, but for the IR range it is advisable to consider other materials that are less sensitive to the temperature effect of the IR laser. The paper analyzes the dependence of the plasmon resonance parameters on the prism material. The possibility of using not only different brands of traditional glass, but also glass ceramics with practically zero coefficient of thermal expansion, semiconductor silicon and chalcogenide glass for the manufacture of prisms is shown.