Interference filter - Polariton-based filter with low angular dispersion

Many optical systems, devices and sensors use the principle of interference - an essential factor in the development and optimization of thin-film devices. The challenge is that thin-film interference inevitably leads to dispersion, i.e., to a change in the wave vector when the system is tilted, and the resonance mode shifts to shorter wavelengths. To eliminate this dependence on angle, an optical resonator is used that contains an absorbing organic material. Inside this resonator, light couples strongly to electronic transitions in the organic material. This kind of film structure can be produced as thin film for use as bandpass filters. 

What sets this invention apart is that, unlike conventional dielectric Fabry-Perot filters, the transmitted wavelength does not depend on the light’s incidence angle. This produces a particularly precise narrow-band characteristic that can be used not only in bandpass filters but also in narrow-band photodetectors.