Ways to reduce the sensitivity of narrowband light filters to the angle of inclusion of radiation

The paper discusses the influence of the angle of incidence of radiation on the main characteristics of narrow-band interference light filters. It is shown that the most sensitive to an increase in the angle of incidence are filters with a minimum half-width. The paper considers a method for correcting the design of the light filter, which makes it possible to reduce the sensitivity of the light filter to the angle of incidence of radiation. An increase in the stability of the position of the transmission maximum in the wavelength scale is achieved by introducing a layer of a material into the structure of the light filter that is not used in the formation of the mirrors included in its composition. An increase in the refractive index of the separating layer by 21% leads to the stability of the position of the passband at the level of 0.99$\lambda_{\mathrm{max}}$ in the angle scale by 11%; and with an increase in the refractive index by 10%, the position stability increases by 8% for narrow-band filters consisting of a 31st layer.