https://doi.org/10.15407/iopt.2020.55.179

Optoelectron. Semicond. Tech. 55, 179-185 (2020)

H.V. Dorozinska,G.V. Dorozinsky, V.P. Sobol, V.V. Vovk, G.M. Androsjuk, V.P. Maslov, N.V. Kachur

INFLUENCE MATERIAL OF PRISM ON THE SENSITIVITY OF SPR SENSORS

Theoretical analysis of the influence of the sensor prism material on the basis of the phenomenon of

surface plasmon resonance (SPR) on its sensitivity and temperature stability of the measurement result is carried out.

The analysis was performed for the infrared wavelength range of excitation surface plasmon radiation (980... 1550 nm)

using materials for prisms with different refractive indices, namely: glass ceramics Zerodur (n D = 1,5423), optical

glasses N-FK51A (n D = 1, 4865) and N-BK7 (n D = 1,5167) with low refractive index, single crystal material CaF 2

(n D = 1.4339), as well as flints N-SF2 (n D = 1,6475) and N-SF11 (n D = 1,7845). The temperature stability of the

measurement result was determined for the temperature range from 20 °C to 70 °C, which corresponds to the operating

temperature range of most refractometers and commercial SPR sensors. The coefficient of temperature shift of the

minimum reflection characteristic for the investigated materials was calculated as the ratio of the magnitude of the

angular shift ∆θ to the corresponding change of temperature ∆Т, which caused this shift. The results of the study

showed that for all materials, regardless of the refractive index value, the temperature effect decreases with increasing

wavelength of radiation. For the material with a lower refractive index (CaF 2 ), the temperature coefficient was 2 times

higher than for flint glass (N-SF11). According to the results of the analysis, it was found that the sensitivity of the SPR

sensor increases threefold from 52.83 deg./RIU to 173.16 deg./RIU when the refractive index of the prism changes from

n D = 1.79 to n D = 1.43. It was also found that increasing the wavelength of the radiation increased both the sensitivity of

the SPR sensor and temperature stability regardless of the prism material. The results of the study can be used both to

develop new SPR sensors and to optimize the modes of operation of existing ones, in particular the choice of optimal

sensitivity at a given range of measurement of the refractive index of the test substance.

Keywords: surface plasmon resonance, prism, sensor, sensitivity.