Dispersive element of the compact spectrometer based on photonic crystal with a modulated photonic bandgap

A compact dispersive element based on a photonic crystal with a modulated period has been experimentally demonstrated. The position of the photonic band gap of this crystal gradually shifts with depth towards long waves, so different spectral components are reflected from different depths of the structure. At inclined incidence, this provides a significant Goos-H¨anchen shift and its strong spectral dependence and contributes to the spatial separation of the spectral components.