A method, system and an apparatus for estimating a property of a fluid in a wellbore are disclosed. In one aspect, the fluid may be exposed to light and light reflected by or passed through the fluid may be separated into a plurality of channels by a plurality of photonic crystals, each providing light corresponding to particular center wavelength. In another aspect, the light may be passed through a plurality of photonic crystals to provide light centered about one or more wavelengths. The fluid then may be exposed to the light output from the photonic crystals. Light detected from the fluid corresponding to each center wavelength is processed to estimate the parameter of interest.