Raytheon Company

Eric C Fest

Jon E Leigh

Page Elizabeth King

Wayne Lee Sunne

Jim Hicks

James P Mills

Ronald L Roncone

Tim P Johnson

Nicholas D Trail

Michael P Schaub

Vijay Murgai

Justan V Forsyth

Rex M Kremer

Jacob A Hanson

Ralph H Shepard, Iii

Page E King

Justan Forsyth

Polarized pixelated filter sub-array is reconfigured to reduce sensitivity to misalignment. The condition number increases more slowly than the standard polarized pixelated filter sub-array as the misalignment increases. In different embodiments, the filter sub-array is configured such that the condition number has a finite bound at &#xbd; pixel misalignment. The angular values of the polarizer filter array are determined to minimize the sensitivity of the condition number of the data reduction matrix to misalignment. This can be achieved by selecting angular values that minimize the expected value of the condition number E(CN) over the range of misalignment.

Polarized pixelated filter array with reduced sensitivity to misalignment for polarimetric imaging

An imaging telescope including a first mirror configured to receive electromagnetic radiation having a first polarization state and to reflect electromagnetic radiation having a second polarization state, the first mirror including a multi-layer dielectric (MLD) coating configured to convert the first polarization state to the second polarization state, and a plurality of reflecting configured to receive the electromagnetic radiation having the second polarization state reflected from the first mirror and to reflect and focus the electromagnetic radiation having the second polarization state onto an image plane of the imaging telescope.

Mirror coating, and method of use, to reduce polarization sensitivity

A method of scattering light includes positioning a Nanocomposite Optical Ceramic (NCOC) diffuser to receive light and scattering the light with the NCOC diffuser. The NCOC diffuser is substantially Lambertian over a waveband range.

Nano diffuser

In flight vehicles subject to extreme aero-thermal heating of the optical window, the optical system is configured to look through an off-axis segment of the optical window and a polarizer is positioned in the optical path between the off-axis segment and the detector. The polarizer comprises at least one filter pixel that imparts a linear polarization of a certain angular value to filter the incident radiation as a function of its polarization. In the case of a sheet polarizer, the entire polarizer is aligned to the plane of incidence. The sheet polarizer preferentially filters the target radiation to increase the SNR at the detector. In the case of a microgrid polarizer, at least one and preferably multiple filter pixels in each sub-array aligned to the plane of incidence. The microgrid polarizer can produce data products including a radiance image, an AoLP image and a DoLP image, only the AoLP image removes the self-emitted window radiance and an gradient caused by non-uniform aero-thermal heating.

Polarization filtering for window self-emission due to aero-thermal heating

A system and method for more accurately generating the surface normal calibration maps &#x3c6;(AoLP) and &#x3b8;(DoLP,&#x3c6;) to compensate for structured scene reflections for 3-D polarimetric imaging. This is accomplished using a microfacet scattering model to develop the functional form of a polarized bidirectional reflectance distribution function (BRDF) of the object surface. The ambient radiance is ray traced to the BRDF to create the calibration maps &#x3c6;(AoLP) and &#x3b8;(DoLP,&#x3c6;), which may be combined into a single calibration map &#x3b8;(DoLP, AoLP). These maps are applied to the AoLP and DoLP images to compute an array of surface normals, which are then mapped to form a 3-D image of the object.

3-D polarimetric imaging using a microfacet scattering model to compensate for structured scene reflections

Optical position encoding mechanisms and methods for use in reimaged optical imaging systems. In one example, a reimaged optical imaging system includes an imaging detector, an optical component, and at least one light source coupled to the optical component and configured to be reimaged onto the imaging detector, wherein a position of an image of the at least one light source at the imaging detector encodes a position of the optical component relative to the imaging detector.

Optical position encoder

An optical component, for example a lens, integrally formed of a nano/nano class nanocomposite optical ceramic (NNCOC) material. The constituent nanograin materials of the NNCOC material are selected to tailor the thermal and optical properties of the lens so as to provide a lens with a substantially constant focal length over an operating temperature range and/or an optical system in which the image position does not change appreciably over the operating temperature range.

Nano-nano-composite optical ceramic lenses

An optical imaging system and method including a movable pixelated filter array, a shutter mechanism to which the pixelated filter array is attached, and a controller configured to implement a data reduction algorithm. The shutter mechanism is configured to move the pixelated filter array into and out of the optical path, and the data reduction algorithm allows the controller to account for axial and/or lateral misalignment of the filter array relative to the imaging detector array or its conjugate. In certain examples, the controller is further configured to use the data reduction algorithms also to perform wavefront sensing, for example to estimate wavefront error.

Movable pixelated filter array

An optical transceiver is provided with a light pipe that intercepts, offsets and redirects a portion of the collimated transmit beam to create a virtual object in the receiver field-of-view to perform the BIT. The light pipe comprises an input face and first reflective surface in the transmitter FOV to intercept a portion of the beam along a first axis and re-direct the beam, a second reflective surface and output face in the receiver FOV that re-directs the portion of the beam along a second axis towards the receiver to create the virtual object in the receiver FOV and an optical channel that guides the redirected portion of the beam from the first reflective surface to the second reflective surface to offset the second axis from the first axis. The same detector used during normal operation of the transceiver is used to perform the BIT, which may include a simple 'on/off' test or a radiometry test. The light pipe may be designed with an acceptance FOV that preserves collimation, which facilitates a measurement of alignment error between the transmit beam and receiver.

Optical transceiver built-in test (BIT)

A polarimeter and method of polarizing incoming light includes an optical assembly, a first adjustable circular retarder that rotates the polarization content of incoming light, a polarization beam splitter that receives light from the adjustable circular retarder and polarizing the light into a first portion of light having a first polarization and a second portion of light having a second polarization. The first portion of light is directed to a focal plane and the second portion of light is directed to the optical assembly. The optical assembly is switchable between a polarizing mode of operation in which the first portion of light is viewable at the focal plane in absence of the second portion of light and an imaging mode of operation in which the first portion of light and the second portion of light are viewable at the focal plane.

Switchable imaging polarimeter and method

The disclosed system and apparatus for a sensor support structure generally includes a substantially reflective support strut having discontinuous protrusions on the support surface presented to the field of view of the sensor. These discontinuous protrusions may be suitably configured such that ambient thermal radiation is generally reflected away from the support strut and divergent from acceptance in the sensor's optical train.

Sensor system and support structure

A receiver including an analyzer and a detector coupled to the output of the analyzer. The analyzer selects a polarized component of a return beam for input to the detector. The analyzer may be linear, circular or elliptical. Coupled with a laser adapted to output a polarized beam, the receiver provides an active optical target detector. An arrangement may be included for compensating for rotation and ellipticity in the returned beam. In one embodiment, the arrangement for compensating for rotation of the orientation of linear polarization in the returned beam includes a Faraday rotator positioned between the transmitter and the analyzer. An arrangement is disclosed for varying the rotation in the returned beam using a Faraday rotator until a maximum transmittance is achieved. In an alternative embodiment, the arrangement for compensating for ellipticity in the returned beam includes an electro-optical modulator positioned between the transmitter and the analyzer. In another alternative embodiment, two electro-optical modulators are included to compensate for any change in the polarization state in the returned beam.

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Tucson, AZ, United States of America

Eric C Fest