A detector assembly for imaging a scene over a predetermined temperature
range and a predetermined wavelength range including a central wavelength
includes an imaging-sensor array, a plurality of focusing elements and a
plurality of optical filtering elements. The imaging-sensor array
includes a plurality of detector-array sections and the focusing elements
are arranged with respect to the detector array such that each focusing
element is capable of focusing upon a corresponding one of the
detector-array sections an image of the scene correlating to the image of
the scene that each of the other focusing elements is capable of focusing
upon the detector-array section corresponding thereto. Each focusing
element and the detector-array section corresponding thereto defines an
associated optical path. Disposed within each optical path is an optical
filtering element such that electromagnetic energy that passes through
that filtering element impinges upon the detector-array section optically
correlated with that filtering element. Each filtering element is
configured to transmit, at a filter-specific maximum intensity, the
central wavelength at a temperature disparate from the temperature at
which each of the other filtering elements is configured to transmit the
central wavelength. The transmittance as a function of temperature for
each filtering element at least partially overlaps the transmittance as a
function of temperature of at least one other filtering element among the
plurality of filtering elements, thereby extending the operative
temperature range of the detector assembly.