Optical spectroscopy utilizing planar spectral filters

An optical spectrometer and/or a method of optical spectroscopy is described herein. One exemplary spectrometer includes a planar spectral filter, a dispersion system, and a detector array having at least two dimensions. The planar spectral filter filters incident light to generate a plurality of wavelength dependent spatial patterns. The dispersion system disperses the spatial patterns along at least one dimension in a wavelength dependent fashion onto the detector array. As a result, spatial patterns corresponding to different wavelengths are centered at different locations on the detector array. The dispersed spatial patterns superimpose at the detector array in an offset but overlapping relationship, creating an asymmetric image that facilitates the spectral analysis of a wide range of light sources, including diffuse or spectrally complex light sources.