Optical spectrometer with variable bandwidth

摘要

With a spectrometer (1) a light beam (5) passes through a variable diaphragm (11) before reaching a refraction grating (12). The reflected beam is then directed by a lens (7) to an optical fibre (10). The smaller the diaphragm stop the fewer grating lines are illuminated and the grating resolution reduced. This enables the output bandwidth to be varied. The refraction grating is a rotatable plane or concave grating.