OPTICAL DEVICE AND IMAGING METHOD

摘要

An optical device comprises a body, the body housing a detector, a diffraction grating and a lens for focusing light reflected by the diffraction grating onto the detector. The body is provided with a window, the window for allowing light to pass from outside of the optical device to the diffraction grating. The diffraction grating, in a preferred embodiment, has a variable pitch, to achieve a linear imaging. The lens comprises a low numerical aperture lens, and the detector is aligned at an angle that is non-perpendicular to the optical axis of the imaging lens.