Spectrograph with tilted detector window

摘要

The spectrograph has a concave holographic grating (4) for diffracting light beam transmitted by an inlet slot (3) and for generating a diffracted light beam and a spectrum in an image plane. A detector (5) e.g. charge coupled device type detector, detects the diffracted light beam, and has an inclined detector window (11) through which the diffracted beam is transmitted, where a part of the diffracted beam generates reflection on the window. An inclination unit having the window inclines the slot to avoid parasite spectrum, where the unit is constituted of a selective filter.