Compact wavelength detection system incorporating a guided-mode resonance filter

The authors demonstrate a compact system for the detection of the peak wavelength value emitted by a light source. The system is composed of only two components, a graded-wavelength guided-mode resonance filter placed before a charge-coupled device sensor array. The filter provides a spatially resolved transmission minimum, the position of which is controlled by the wavelength of the incoming light. The sensor array collects the spatially resolved transmitted intensity and the wavelength is determined by recording the position of the transmission minimum along its length. Using this technique, wavelength changes as small as 0.011 nm can be detected.