A spectral radiation detector employs at least one lenslet with a circular blazed grating for diffraction of radiation at a wavelength at nth order to a focal plane A detector is mounted at the focal plane receiving radiation passing through the at least one lenslet for detection at a predetermined order. At least one order filter associated with the at least one lenslet passes radiation at wavelengths corresponding to the predetermined order. In additional embodiments a polarizing filter is associated with the lenslet for additional discrimination of the radiation.