Spatial light modulator spectroscopy

Apparatus comprising:

• a light source directed to a test object;
• a slit receiving light from the test object;
• a spectrum dispersion device receiving light from the slit to provide a spectrum;
• a controller;
• a spatial light modulator including groups of pixels, wherein each group is arranged to transmit only a respective portion of a light spectrum, the respective portion has a respective dominant color, each group is controlled by a respective reset signal, and the spatial light modulator is coupled to receive a selection from the controller and in response to the selection:
• cause a selected one of the groups to transmit its respective portion of the light spectrum;
• and cause an unselected one of the groups to block transmission of its respective portion of the light spectrum;
• and
• a photodetector coupled to:
• receive the respective portion of the light spectrum transmitted by the selected group;
• and output an intensity signal indicating an intensity thereof;
• wherein the respective portions of the light spectrum are distinct from one another, according to their respective dominant colors.