Compact wide field imager for enhanced laser detection

A method for analyzing light comprising:

• a) providing a light path, extending through an aperture, for light from a light source located at an angular direction;
• b) disposing a diffraction element in the light path for the apertured light;
• c) defining a first image plane in the path of diffracted light from the diffraction element, wherein a diffracted light pattern comprises at least two diffraction orders of light from the light source, wherein the diffracted light pattern is indicative of the angular direction and of a spectral content of the light source, and wherein a magnitude of high spatial frequency intensity oscillations within at least one non-zero diffraction order at the first image plane is further indicative of a spectral width of the light source;
• d) capturing the light pattern with an image sensor having an array of pixels, wherein the image sensor pixel array area is at least 10 times larger than the light-transmitting area of the aperture and wherein the pixels are sufficiently small to distinguish at least some of the high spatial frequency intensity oscillations within the at least one non-zero diffraction order;
• e) analyzing the light pattern based on (i) a position and size of the diffraction orders and (ii) the magnitude of the high spatial frequency intensity oscillations within the at least one non-zero diffraction order;
• and
• f) reporting characteristics indicative of spectral content of the light source.

An apparatus for characterization of one or more light sources over a field of view, comprising:

• a) an image relay disposed to relay a first image plane to a second image plane;
• b) an aperture having a light-transmitting area disposed to define the field of view at the first image plane;
• c) a diffraction grating in the path of light through the aperture and configured to form, on the first image plane, for at least one light source, a light pattern having at least two diffraction orders of light from the corresponding light source, wherein the light path to the first image plane is not focused;
• d) an image sensor having an array of pixels configured to provide image data from the light pattern at the second image plane, wherein each pixel area in the array is less than 1% of the aperture light-transmitting area;
• and
• e) a control logic processor in communication with the image sensor and configured to analyze the light pattern of the corresponding light source and to report either or both (i) an angular direction of the light source and (ii) characteristics indicative of a spectral content of the light source.