Tandem dispersive range monochromator

摘要

Aspects of a tandem dispersive range monochromator are described herein. In one embodiment, the monochromator includes a light source that provides broadband light, a tandem diffraction grating including a first diffraction grating and a second diffraction grating, a grating drive motor that rotates the tandem diffraction grating to provide dispersed wavelengths of light, a detector that detects a portion of the dispersed wavelengths of light, and processing circuitry that controls a grating drive motor to regulate an angular velocity of the tandem grating based on an angular orientation of the tandem diffraction grating. By using a tandem diffraction grating having different dispersive surfaces, measurements of relatively high precision and quality may be taken throughout a wider spectral range. In another aspect, the processing circuitry controls a sample drive motor to vary an angle of incidence of the dispersed wavelengths of light onto a sample for evaluation.

主权项

1. A monochromator, comprising:
a light source that provides broadband light; a tandem diffraction grating including a first diffraction grating, a second diffraction grating, and a mounting assembly having a rotatable shaft to rotate the tandem diffraction grating; a grating drive motor that rotates the tandem diffraction grating about a pivot point of the rotatable shaft to provide dispersed wavelengths of light by diffraction of the broadband light; an exit slit that passes at least a portion of the dispersed wavelengths of light onto a sample tray that holds a sample for evaluation; a detector that detects a reflection of the portion of the dispersed wavelengths of light off the sample; and processing circuitry that controls the grating drive motor to regulate a first angular velocity of the tandem diffraction grating over a first range of motion for the first diffraction grating and a second angular velocity of the tandem diffraction grating over a second range of motion for the second diffraction grating based on an angular orientation of the tandem diffraction grating and an offset distance between the pivot point of the rotatable shaft and at least one of the first diffraction grating or the second diffraction grating.