Abstract: A low-cost optics, broadband, astigmatism-corrected practical spectrometer. An off-the-shelf cylindrical lens is used to remove astigmatism over the full bandwidth, providing better than 0.1 nm spectral resolution and more than 50% throughput over a bandwidth of 400 nm centered at 800 nm. The spectrometer includes a first spherical mirror disposed along an optical path in an off-axis (tilted) orientation; a diffraction grating disposed along the optical axis in a location optically downstream from the first mirror; a second spherical mirror disposed along the optical path in an off-axis orientation in a location optically downstream from the diffraction grating; a cylindrical optic disposed in the optical path; and a detector disposed in the optical path in a location optically downstream from the second spherical mirror.

Abstract: A low-cost optics, broadband, astigmatism-corrected practical spectrometer. An off-the-shelf cylindrical lens is used to remove astigmatism over the full bandwidth, providing better than 0.1 nm spectral resolution and more than 50% through-put over a bandwidth of 400 nm centered at 800 nm. The spectrometer includes a first spherical mirror disposed along an optical path in an off-axis (tilted) orientation; a diffraction grating disposed along the optical axis in a location optically downstream from the first mirror; a second spherical mirror disposed along the optical path in an off-axis orientation in a location optically down-stream from the diffraction grating; a cylindrical optic disposed in the optical path; and a detector disposed in the optical path in a location optically downstream from the second spherical mirror.

Abstract: An optical system suitable for use in an optical instrument such as a handheld optical probe, the optical system including a scanning element and an objective, the objective including a variable focus lens that can be electronically controlled to change the focal length of the optical system. In some embodiments, the optical system can axially and laterally scan a subject material by sequentially focusing at an axial depth using the variable focus lens and laterally scanning the material at that depth using the scanning element.

Abstract: An optical system suitable for use in an optical instrument such as a handheld optical probe, the optical system including a scanning element and an objective, the objective including a variable focus lens that can be electronically controlled to change the focal length of the optical system. In some embodiments, the optical system can axially and laterally scan a subject material by sequentially focusing at an axial depth using the variable focus lens and laterally scanning the material at that depth using the scanning element.

Abstract: Apparatus and method are disclosed for obtaining from a two dimensional field of view containing numerous unresolved sources of irradiation of various unknown wavelengths, the wavelengths incident on objects in the field using significantly fewer pixels than required if a conventional imaging spectrometer were employed. A reflective telescope (10, 12) includes a concave reflective grating (14) after the secondary mirror (12). Undiffracted radiation from the grating forms an image on a first detector array (16). Diffracted radiation forms an image on a second detector array (18). The zero order images provide spatial identification of the objects and a set of wavelength independent reference locations from which the relative displacement of the diffracted radiation provides spectral information.