Hyperspectral imaging system, monolithic spectrometer and methods for manufacturing the monolithic spectrometer

摘要

A hyperspectral imaging system, a monolithic Offner spectrometer, and two methods for manufacturing the monolithic Offner spectrometer are described herein. In one embodiment, the monolithic Offner spectrometer comprises a transmissive material which has: (1) an entrance surface which has an opaque material applied thereto, where the opaque material has a portion removed therefrom which forms a slit; (2) a first surface which has a first reflective coating applied thereto to form a first mirror; (3) a second surface which has a second reflective coating applied thereto to form a diffraction grating; (4) a third surface which has a third reflective coating applied thereto to form a second mirror; and (5) an exit surface.

主权项

1. A hyperspectral imaging system for imaging a remote object, the hyperspectral imaging system comprising:
a housing; fore optics, attached to the housing, where the fore optics are configured to receive a beam from the remote object; a detector attached to the housing; and a monolithic Offner spectrometer positioned inside the housing, the monolithic Offner spectrometer comprising:
a transmissive material which has:an entrance surface which has an opaque material applied thereto, where the opaque material has an opening therein which forms a slit that is configured for receiving and passing a portion of a beam received from the fore optics;a first surface which has a first reflective coating applied thereto to form a first mirror, where the first mirror is configured for receiving and reflecting the beam that passed through the slit;a second surface which has a second reflective coating applied thereto to form a diffraction grating, where the diffraction grating is configured for receiving, diffracting and reflecting the beam received from the first mirror;a third surface which has a third reflective coating applied thereto to form a second mirror, where the second mirror is configured for receiving and reflecting the diffracted beam received from the diffraction grating; andan exit surface for passing there through the diffracted beam reflected from the second mirror to the detector; where the monolithic Offner spectrometer is configured according to:
dx/dλ=f*dθ/dλ=f*/(2*(d/n)*cos(φ)*cos(θ))where:
dx/dλ is a linear dispersion in a range of 4-200 mm/μm; f is a focal length in a range of 10-300 mm which is measured from the diffraction grating to the focal plane detector; d is the period of the linear gratings in a range of 3-1000 μm; n is an order of diffraction in a range of 1-10; φ is an Ebert angle in a range of 1-30° and is measured from incident to normal; θ is a diffracted angle in a range of 0.2-45° and is measured from normal to diffracted order.