An orthoscopic, apochromatic lens is suitable for deployment such as on aerial platforms provides distortion less than 0.2% over a full field of view of more than 60° with F # less than 6.5 and focal length greater than 3″, and in embodiments greater than 5″. Embodiments are apochromatic from 500 to 950 nm to within 7 microns. Embodiments have an overall length of less than 7″. The lens includes five optical groups with an aperture stop between the second and third groups. The optical groups have one, one, two, one and one optical element each, as ordered from the object to the image plane, and have positive, negative, positive, positive, and negative optical powers, respectively. Embodiments are telephoto. In embodiments the focal length is temperature invariant within 0.0015 inches from 0° C. to 40° C.

Orthoscopic projection lens

A compact orthoscopic lens is corrected for monochromatic and chromatic aberrations over wavelengths from 450 to 2450 nm with an angular FOV of 5.56° vertical and 66° horizontal. The 4.36″ effective focal length lens with f-number of 4 is compact measuring 5.2″ from the first optical surface to the image. The lens includes, in order from object to image, a first optical group having a negative optical power; a second optical group having a positive optical power and a third optical group having a negative optical power. The first optical group consists of two elements, the second optical group consists of three elements, one a doublet, and the third optical group consists of two elements. A physical aperture stop is positioned inside the second optical group. Powers of groups and elements, shapes, refractive indices, Abbe numbers and partial dispersions of glasses are selected so the lens is apochromatic and orthoscopic.

Compact orthoscopic VNIR/SWIR lens

An off-axis optical system having a rectangular aperture stop to control rays of incident electromagnetic radiation passing through the optical system along an optical path is provided. The optical system includes one or more optical surfaces along the optical path, each surface being configured to change a direction of each ray on the surface based on a location of the ray relative to the surface. At least one of the surfaces is conjugate to and has the same shape as the rectangular aperture stop. In one embodiment, each optical surface is shaped to avoid vignetting the rays. In one embodiment, the optical system is a three-mirror anastigmat (TMA) and includes a concave primary mirror to collect and focus the electromagnetic radiation; a curved secondary mirror to reflect the electromagnetic radiation focused by the primary mirror; and a concave tertiary mirror to focus the electromagnetic radiation reflected by the secondary mirror.

Three-mirror anastigmat having rectangular aperture stop

A Compact and Athermal VNIR/SWIR Spectrometer utilizes a slit, a Mangin lens, a pupil lens adjacent to the diffraction grating, corrector lenses, a beam splitter, field lenses and SWIR and VNIR FPAs. In examples, two corrector lenses are used. Some examples do not utilize field lenses and beam splitter, some examples utilize only the SWIR radiation spectrum. By balancing the powers of the optical elements and Abbe numbers of glasses as well as usage of aspheric surfaces combinations, a monochromatic and polychromatic aberrational correction is achieved; by balancing optical elements refractive indices change with temperature an athermalization is achieved. The overall length of the spectrometer does not exceed 4 inches, and in some examples it is 2.5 inches. A wide field of view and a low F number are obtained with an operating wavelength range from approximately 400 to 2350 nm. The spectrometer is particularly suited to airborne applications.

Russo Jr Michael J

Papers

Compact orthoscopic VNIR/SWIR lens

Orthoscopic projection lens

Three-mirror anastigmat having rectangular aperture stop

Compact and athermal VNIR/SWIR spectrometer