Abstract: A multi-telescope imaging system includes a first telescope and a second telescope, each telescope having an input line of sight, a ray path that is incident upon a focal surface imaging location at a non-normal angle of incidence, and a shutter lying on the ray path. A single common sensor lies at the focal surface imaging location, such that the first-telescope ray path and the second-telescope ray path are alternatingly incident upon the same focal surface imaging location of the sensor. A shutter controller alternatingly opens and closes the two shutters, so that the sensor alternatingly views the scenes imaged by the two telescopes.

Abstract: A two-channel spectrometer has a shared objective and a pair of slits at a common image plane. Each of the slits receives a portion of the output beam of the shared objective and is optimized for transmitting different wavelengths. A shared double-pass reflective triplet receives the output beams of the slits. The output of the reflective triplet is incident upon a beamsplitter, which sends a collimated first reflective triplet output of a first wavelength to a first dispersive element, and a collimated second reflective triplet output of a second wavelength to a second dispersive element. The outputs of the dispersive elements are directed back to the beamsplitter and the reflective triplet to imaging detectors located at two different locations of the common image plane.

Abstract: An imaging device includes a refractive imager lying in an optical path, and optionally a telescope that directs the optical path to the refractive imager. The refractive imager includes a first lens group that forms an intermediate image of a scene on the optical path, wherein the first lens group includes a first-lens-group positive-power lens, and a first-lens-group negative-power lens. A second lens group relays the intermediate image to a final image surface on the optical path, wherein the second lens group includes a second-lens-group positive-power lens, and a second-lens-group negative-power lens. A third lens group may be selectively inserted into the optical path between the first lens group and the second lens group and selectively removed from the optical path. The third lens group includes a third-lens-group positive-power lens, and a third-lens-group negative-power lens.

Abstract: An all-reflective optical system includes an all-reflective afocal module, an all-reflective imaging module and an all-reflective switching structure being operated to direct a light beam through the afocal module and the imaging module. A first position of the switching structure directs the light beam to enter the first optical end of the afocal module and exit the second optical end of the afocal module, and thereafter to enter the input optical end of the imaging module. A second position of the switching structure directs the light beam to enter the second optical end of the afocal module and exit the first optical end of the afocal module, and thereafter to enter the input optical end of the imaging module. A third position of the switching structure directs the light beam to enter the input optical end of the imaging module so that the light beam completely bypasses the afocal module.

Abstract: An imaging spectrometer includes an all-reflective objective module that receives an image input and produces an objective module output at an exit slit, and an all-reflective collimating-and-imaging module that receives the objective module output as an objective-end input and produces a collimating-end output, wherein the collimating-and-imaging module comprises a reflective triplet. A dispersive element receives the collimating-end output and produces a dispersive-end input into the collimating-and-imaging module that is reflected through the collimating-and-imaging module to produce a spectral-image-end output. An imaging detector receives the spectral-image-end output of the collimating-and-imaging module. The objective module may be a three-mirror anastigmat having an integral corrector mirror therein, or an all-reflective, relayed optical system comprising a set of five powered mirrors whose powers sum to substantially zero.

Abstract: A wide field of view imaging system (100). The novel system (100) includes a rotating mirror (18) having two reflective surfaces each surface, respectively, reflecting light from a scene to first and second sensors (10, 12) positioned to receive light from the mirror (18), wherein the first and second sensors (10, 12) each occupy a different portion of the volume surrounding the mirror (18). In the illustrative embodiment, the mirror (18) is a flat, double-sided mirror rotating at a constant velocity about an axis parallel with the surface of the mirror (18). The first and second sensors (10, 12) are all-reflective optical systems, with the first sensor (10) opposite the second sensor (12). In the preferred embodiment, the invention further includes third and fourth opposing sensors (14, 16) clocked 90° from the first and second sensors (10, 12).

Abstract: An infrared imaging optical system includes a front lens group having negative optical power, wherein the front lens group comprises a front lens having a refractive index of from about 2.0 to about 3.0; an intermediate lens group that receives an infrared light beam from the front lens group, wherein the intermediate lens group comprises an intermediate lens having a refractive index of from about 1.35 to about 2.0; and a rear lens group having positive optical power, wherein the rear lens group receives the infrared light beam from the intermediate lens group, wherein the rear lens group comprises a rear lens having a refractive index of from about 2.0 to about 3.0, and wherein at least two of the front lens, the intermediate lens, and the rear lens have at least one aspheric surface thereon. The infrared imaging optical system further includes an infrared detector that receives the infrared light beam from the rear lens group. There is a pupil located between the rear lens group and the detector.

Abstract: A system and method for simultaneous imaging of both infrared and millimeter wave radiation. The novel optical system (10) includes a primary mirror (20), a Mangin secondary mirror (30) positioned to receive energy reflected from the primary mirror (20), and an immersion lens (40) for focusing energy received from the Mangin mirror (30). In the illustrative embodiment, the primary mirror (20) and Mangin mirror (30) are arranged in a Cassegrain configuration. Central to this invention is the use of a negative power refractive Mangin mirror (30) as the Cassegrain secondary mirror, so that the field curvature of the secondary mirror (30) and immersion lens (40) can be made to cancel. The immersion lens (40) effectively decreases the wavelength of the millimeter wave radiation, allowing a smaller detector to collect the same amount of radiation as would a larger detector in air.

Abstract: An all-reflective, relayed optical system is arranged along a beam path. The optical system includes a first mirror having positive optical power, and a second mirror having a negative optical power, wherein the second mirror receives the beam path reflected from the first mirror and wherein an intermediate image is formed after the beam path reflects from the second mirror. The optical system further includes a third mirror having positive optical power, wherein the intermediate image on the beam path is reflected from the third mirror; a fourth mirror having a negative optical power, wherein the beam path reflected by the third mirror is reflected by the fourth mirror, and a fifth mirror having positive optical power, wherein the beam path reflected by the fourth mirror is reflected by the fifth mirror to an image location.

Abstract: An imaging spectrometer includes an all-reflective objective module that receives an image input and produces an objective module output at an exit slit, and an all-reflective collimating-and-imaging module that receives the objective module output as an objective-end input and produces a collimating-end output, wherein the collimating-and-imaging module comprises a reflective triplet. A dispersive element receives the collimating-end output and produces a dispersive-end input into the collimating-and-imaging module that is reflected through the collimating-and-imaging module to produce a spectral-image-end output. An imaging detector receives the spectral-image-end output of the collimating-and-imaging module. The objective module may be a three-mirror anastigmat having an integral corrector mirror therein, or an all-reflective, relayed optical system comprising a set of five powered mirrors whose powers sum to substantially zero.

Abstract: A system and method for focusing infrared detectors operable at cryogenic temperatures. The invention includes a sensor (10) for detecting electromagnetic energy comprising a first detector (14) operable over a first temperature range and a predetermined number of auxiliary detectors (12) operable over a second temperature range, wherein the auxiliary detectors (12) are adjacent to and in the same optical plane as the first detector (14). In the illustrative embodiment, the energy is infrared or visible light, the first temperature range is a range of cryogenic temperatures, and the second temperature range is a range of ambient temperatures. The first detector (14) is a focal plane array and the auxiliary detectors (12) are uncooled detector arrays. In the preferred embodiment, the focal plane array (14) and the uncooled detectors (12) are disposed on a common substrate.

Abstract: A laser beam pointing and positioning system includes first and second rotatable diffraction gratings. Each grating deviates a laser beam by a predetermined angle of deviation. The relative rotational position of the gratings is controlled to change the beam steering angle and direction of a laser beam. A maximum beam steering angle of twice the angle of deviation may be achieved in any direction. The diffraction gratings may be etched on transmissive substrates of optical glass, sapphire, silicon (Si), Zinc Selenide (ZnSe), Zinc Sulfide (ZnS), or Germanium (Ge). The substrates may be positioned within rotary elements coupled respectively to electromechanical positional control elements to rotate the gratings.

Abstract: An optical system comprises a three-mirror anastigmat including a primary mirror, a secondary mirror, and a tertiary mirror positioned to reflect a beam path. An intermediate image is formed on the beam path at an intermediate-image location between the secondary mirror and the tertiary mirror. A negative-optical-power field mirror is positioned in the beam path at a field-mirror location subsequent to the intermediate-image location along the beam path. The field mirror reflects the intermediate image to the tertiary mirror.

Abstract: A multi-layer anti-reflection coating for simultaneously coupling electromagnetic radiation of two different wavelengths, &lgr;1 and &lgr;2, where &lgr;1 is greater than &lgr;2, from a first region into a second region is provided. The first region has an index of refraction that is smaller than that of the second region. The anti-reflection coating comprises three layers: (a) a first layer and a third layer that are essentially invisible to &lgr;1 and serve to reduce Fresnel losses for &lgr;2 and (b) a second layer sandwiched between the first and third layers that serves to reduce Fresnel losses for &lgr;1. The thickness and the index of refraction are calculated for each layer.

Abstract: An imaging spectrometer includes an all-reflective objective module that receives an image input and produces an objective module output at an exit slit, and an all-reflective collimating-and-imaging module that receives the objective module output as an objective-end input and produces a collimating-end output, wherein the collimating-and-imaging module comprises a reflective triplet. A dispersive element receives the collimating-end output and produces a dispersive-end input into the collimating-and-imaging module that is reflected through the collimating-and-imaging module to produce a spectral-image-end output. An imaging detector that receives the spectral-image-end output of the collimating-and-imaging module. The objective module may be a three-mirror anastigmat having an integral corrector mirror therein, or an all-reflective, relayed optical system comprising a set of five powered mirrors whose powers sum to substantially zero.

Abstract: A system and method for focusing infrared detectors operable at cryogenic temperatures. The invention includes a sensor (10) for detecting electromagnetic energy comprising a first detector (14) operable over a first temperature range and a predetermined number of auxiliary detectors (12) operable over a second temperature range, wherein the auxiliary detectors (12) are adjacent to and in the same optical plane as the first detector (14). In the illustrative embodiment, the energy is infrared or visible light, the first temperature range is a range of cryogenic temperatures, and the second temperature range is a range of ambient temperatures. The first detector (14) is a focal plane array and the auxiliary detectors (12) are uncooled detector arrays. In the preferred embodiment, the focal plane array (14) and the uncooled detectors (12) are disposed on a common substrate.

Abstract: A system and method for simultaneous imaging of both infrared and millimeter wave radiation. The novel optical system (10) includes a primary mirror (20), a Mangin secondary mirror (30) positioned to receive energy reflected from the primary mirror (20), and an immersion lens (40) for focusing energy received from the Mangin mirror (30). In the illustrative embodiment, the primary mirror (20) and Mangin mirror (30) are arranged in a Cassegrain configuration. Central to this invention is the use of a negative power refractive Mangin mirror (30) as the Cassegrain secondary mirror, so that the field curvature of the secondary mirror (30) and immersion lens (40) can be made to cancel. The immersion lens (40) effectively decreases the wavelength of the millimeter wave radiation, allowing a smaller detector to collect the same amount of radiation as would a larger detector in air.

Abstract: A system (200) for effecting low-order aberration correction of a beam of electromagnetic energy. The inventive system (200) includes a first mechanism (220), including at least one articulated optical element (222), for receiving and correcting the beam; a second mechanism (270) for generating a signal indicative of the aberrations to be corrected; and a third mechanism (226), responsive to the second mechanism (270), for adjusting the position of the optical element (222) to generate an output beam that is at least partially compensated with respect to the aberrations. In the preferred embodiment, the first mechanism (220) is a telescope comprising a fixed primary lens or mirror (224) and an articulated secondary lens or mirror (222). The second mechanism (270) includes a wavefront error sensor for detecting aberrations in the received beam.

Abstract: An optical system comprises a three-mirror anastigmat including a primary mirror, a secondary mirror, and a tertiary mirror positioned to reflect a beam path. An intermediate image is formed on the beam path at an intermediate-image location between the secondary mirror and the tertiary mirror. A negative-optical-power field mirror is positioned in the beam path at a field-mirror location subsequent to the intermediate-image location along the beam path. The field mirror reflects the intermediate image to the tertiary mirror.

Abstract: A laser beam pointing and positioning system includes first and second rotatable diffraction gratings. Each grating deviates a laser beam by a predetermined angle of deviation. The relative rotational position of the gratings is controlled to change the beam steering angle and direction of a laser beam. A maximum beam steering angle of twice the angle of deviation may be achieved in any direction. The diffraction gratings may be etched on transmissive substrates of optical glass, sapphire, silicon (Si), Zinc Selenide (ZnSe), Zinc Sulfide (ZnS), or Germanium (Ge). The substrates may be positioned within rotary elements coupled respectively to electromechanical positional control elements to rotate the gratings.