Qinetiq Limited

The Secretary of State for Defence in Her Britannic Majesty's Government

Barr & Stroud Limited

The Secretary of State for Defence in Her Brittanic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland

Keith Loder Lewis

Mark Edward McNie

Christopher William Slinger

Kevin Michael Brunson

Andrew Maxwell Scott

Gilbert William Smith

Ian Charles Sage

Ian Robert Mason

James A Savage

Ewan M Waddell

Richard Simon Blacker

Christopher J Kelly

Kevin Dennis Ridley

David J Jackson

Douglas Alan Levenets

Kevin Roy Welford

Desmond Robert Gibson

Christopher William Qinetiq Limited Slinger

A retro-reflective identification tag capable of modulating an optical signal whereby to support bi-directional communication with an associated remote optical interrogation device. The tag comprises a MOEMS modulating layer over a retro-reflective substrate, giving the tag a wide angle of effective operation. The tag modulator may optionally be switched on only responsive to detection of a precursor beam from the interrogation system in order to save power. The interrogation device may make use of multiple optical wavelengths for communicating with the tag.

Dynamic optical reflector and interrogation system

In coded aperture imaging knowledge of the coded array pattern and its positional relation to the detector array is needed in order to be able to reconstruct the scene image. Usually a theoretical model of the coded array is used and the actual array needs to be aligned accurately with respect to the detector. The present invention uses a coded aperture imager to image a reference object in the scene and uses the intensity pattern on the detector array to determine the decoding pattern corresponding to the coded aperture array. The reference object may be a point source in which case the pattern on the detector array may be used directly as the decoding pattern or it may be used to correct a theoretical pattern for any misalignment.

Coded aperture imaging using successive imaging of a reference object at different positions

A micro-opto-electro-mechanical systems (MOEMS) electro optical modulator () having an electrically tuneable optical resonator comprising an asymmetric Fabry-Perot etalon incorporating a mirror () resiliency biased with respect to a substrate () and moveable in relation thereto in response to a voltage applied there-between. The optical modulator () is capable of modulating electromagnetic radiation having a plurality of wavelengths. The modulator is adapted to modulate the transmission of short wave infrared radiation (SWIR), medium wave infrared radiation (MWIR) and long wave infrared radiation (LWIR) and the reflection of visible radiation. A spatial optical modulator having a plurality of said MOEMS optical modulators (). A method of addressing said spatial optical modulator.

Optical modulator

This invention relates to coded aperture imaging apparatus and methods. In one aspect a coded aperture imager has at least one detector array and a reconfigurable coded aperture mask means. A reconfigurable coded aperture mask means can display various coded aperture masks to provide imaging across different fields of view and/or with different resolution without requiring any moving parts or bulky optical components. More than one detector array can be used to provide large area imaging without requiring seamless tiling and this represents another aspect of the invention. The present invention also relates to the use of coded aperture imaging in the visible, ultraviolet or infrared wavebands. The use of coded aperture imaging for imaging through a curved optical element is taught as the image decoding can automatically remove any aberrations introduced by the curved element.

Coded aperture imaging system having adjustable imaging performance with a reconfigurable coded aperture mask

An optical interference filter () is provided by a substrate () in which is formed a plurality of parallel slots so as to define layers (slots and substrate laminae) of alternating refractive index. As shown, the filter comprises a central Fabry-Perot resonator slot cavity () between two mirror groups () of alternating slots and substrate laminae, and is coupled to optical fibers () accommodated in V-grooves () on either side. For tuning, one mirror group () may be movable in the direction of arrow (A), or, where the central resonator is provided by substrate material, by altering its temperature. One or more further Fabry-Perot filters may be formed in the substrate and coupled to the filter (). The invention encompasses non-resonating filters.

Optical filters

Optical filters ( ) designed in pairs, which are essentially colourless in their individual general appearance designed to take on a strong coloration when viewed together in transmission, said filters being particularly, useful for identification of counterfeit articles. The optical filters ( ) utilize resonantly-coupled Fabry-Perot etalons of, an asymmetric design. The filters ( ) are configured such that one of the Fabry-Perot cavities within the filter incorporates an additional multiple quarter wave thickness layer ( ), said additional layer having a contrasting refractive index to that of the cavity spacer.

Multilayer optical filters

A tunable filter in particular for use in the visible or near infrared wavelength region, comprising a nano dispersed composite material contained within a resonant cavity structure comprising dielectric mirrors (,), where the material is polarizable by means of an applied electric field. In particular, the polarizable material may be a nano phase polymer dispersed liquid crystal (PDLC) material where the diameter of liquid crystal droplets (,) within the material (,) is less than 0.1 &mgr;m, and for use in the visible wavelength region is typically between 10 nm and 50 nm. The filter also comprises structure for applying a variable electric field across the faces of the material. The transmission-wavelength characteristic of the filter is such that maxima and minima are shifted in wavelength by varying the electric field.

Tunable nano-phase polymer dispersed liquid crystal filter

Anti counterfeit apparatus

An optical component having a protective layer provided on a surface thereof, the protective layer preventing the component from being damaged by high velocity impacts from small particles or water droplets. The protective coating comprises a layer of gallium phosphide deposited onto the component surface using plasma assisted chemical vapour deposition (PACVD), an intermediate layer of PACVD boron phosphide, and an outer layer of PACVD diamond-like-carbon.

Protective coatings for optical components

Infrared transmitting optical components having a wide variety of substrates (e.g. ZnS, ZnSe, Ge, Si, SiO.sub.2) are disclosed all with an optical coating of boron phosphide (BP). The boron phosphide may be a single layer coating or one layer of a multilayer coating in which case it is preferably the penultimate layer. Coated components are provided which are very low in absorption, which are operable at high temperatures with minimal transmission loss, and which are transmitting in two IR wavebands. The boron phosphide layer is deposited by plasma-assisted chemical vapor deposition at a temperature in the range 300.degree.-500.degree. C. preferably using feedstock gases which are hydrogen-fee. Boron phosphide coatings of up to 40 .mu.m in thickness have been achieved.

Infra-red transmitting optical components and optical coatings therefor

A coating having low absorbance of laser energy is provided on optical components substrates by molecular beam epitaxial growth techniques. The growth conditions prevent contamination of substrate and coating with water and carbonaceous gases. The method of coating has the following steps:

Growing community of inventors

Malvern, United Kingdom

Keith Loder Lewis