Abstract: An optical system (100) comprising: a transmitter module (102) configured to transmit a sequence of optical pulses (300), each optical pulse in the sequence (300) having a different magnitude to each other optical pulse in the sequence (300); a receiver module (104) comprising one or more optical signal detectors, the receiver module (104) configured to receive the sequence of optical pulses (300) transmitted by the transmitter module (102); and one or more processors (110) configured to process the sequence of optical pulses received by the receiver module (104) to select an optical pulse from the received sequence of optical pulses (400) based on one or more predetermined criteria. The one or more predetermined criteria include a criterion that the selected optical pulse does not saturate the one or more optical signal detectors.

Abstract: A coating material (10) for coating an article is described. The coating material (10) comprises a surface (100) having an optical interference coating (110) thereon. The coating material (10) improves protection of the article from incident electromagnetic radiation having a predetermined wavelength. The coating material (10) may retroreflect at least some of the incident electromagnetic radiation, for example towards a source (e.g. a laser) thereof. An article having a coating provided by such a coating material and methods of providing such coating materials are also described.

Abstract: A system for remotely sensing light from within a monitored environment containing one or more retro-reflective optical elements. The system includes an illuminator including a light source and a reflector unit comprising a deformable mirror arranged to receive light from the light source and to reflect the received light. This outputs illumination light from the illuminator for illuminating the optical element(s) within the monitored environment. A detector is arranged to receive light returned by the one or more retro-reflective optical elements in response to the illumination light. The detector determines a wavefront of the returned light and detects a property of the monitored environment according to the returned light. The reflector unit is arranged to deform the deformable mirror according to the determined wavefront such that light from the light source is reflected by the deformable mirror so deformed to output illumination light with a modified wavefront.

Abstract: According to a first aspect of the present invention, there is provided a method for transmitting and/or receiving an optical signal through a fluid, the method comprising: using a pressure wave to cause a change in refractive index in the fluid, the change in refractive index causing a waveguide to be formed; and transmitting and/or receiving the optical signal through the waveguide.

Abstract: A system for remotely sensing light emanating from within a monitored environment. The system comprises one or more retro-reflective optical elements bearing an optically reflective optical coating upon a surface thereof and positionable within the environment to be monitored, and a light source arranged to direct a beam of light at the optical element(s). A detector is arranged to receive from the optical element(s) light returned by the optical coating in response to the beam of light and to detect a property of the monitored environment according to said returned light. The optical element includes a body comprising a focuser part of positive optical power partly surrounded by a reflector part separated therefrom and connected thereto across an open spacing. The optical coating is arranged over an outer surface of the reflector part thereat to receive light which has been at least partially converged by the focuser part for subsequent retro-reflection.

Abstract: A method of forming a filter, comprising the steps of: —selecting at least a first wavelength corresponding to a predetermined laser threat and having a first colour in the visible spectrum; —providing a generally transparent substrate and forming a first notch filter region therein configured to substantially block incident radiation thereon of wavelengths within a first predetermined wavelength band including said first wavelength; —selecting a second wavelength having a second colour in the visible spectrum and forming a colour balancing notch filter region in said substrate configured to block incident radiation thereon of wavelengths within a wavelength band including said second wavelength, thereby to balance or neutralise any colour distortion of said substrate caused by said first notch filter region.

Abstract: There is disclosed a filter for a vehicle window comprising a layer of filter material, the layer of filter material being for substantially preventing the transmission of radiation at a first predetermined visible wavelength band, the first predetermined visible wavelength band covering the wavelength of a predetermined laser threat, whilst substantially allowing visible wavelengths outside of the band to be transmitted, such that the filter can offer a visible light transmission of at least 70%, and a radiation detector, such that radiation at the first predetermined wavelength band can be detected.

Abstract: According to a first aspect of the present invention, there is provided a method for transmitting and/or receiving an optical signal through a fluid, the method comprising: using a pressure wave to cause a change in refractive index in the fluid, the change in refractive index causing a waveguide to be formed; and transmitting and/or receiving the optical signal through the waveguide.

Abstract: A free space optical communication system receiver (500) comprising: a central optical sensor (600); and a plurality of further optical sensors (601-604) disposed around a peripheral edge of the central optical sensor (600). The free space optical communication system receiver (500) may be coupled to means for moving the free space optical communication system receiver (500) relative to an incoming optical signal (510). A controller (508) may be configured to, using measurements of the incident optical signal (510) by the plurality of further optical sensors (601-604), control the means so as to move the free space optical communication system receiver (500) relative to the incident optical signal (510).

Abstract: A method of forming a filter, comprising the steps of:—selecting at least a first wavelength corresponding to a predetermined laser threat and having a first colour in the visible spectrum;—providing a generally transparent substrate and forming a first notch filter region therein configured to substantially block incident radiation thereon of wavelengths within a first predetermined wavelength band including said first wavelength;—selecting a second wavelength having a second colour in the visible spectrum and forming a colour balancing notch filter region in said substrate configured to block incident radiation thereon of wavelengths within a wavelength band including said second wavelength, thereby to balance or neutralise any colour distortion of said substrate caused by said first notch filter region.

Abstract: A method of forming a conformable filter, comprising the steps of: —selecting at least a first wavelength corresponding to a predetermined laser threat; —providing a conformable photosensitive film (320) and exposing said film to radiation from a focused laser source (100) of said first wavelength to create a first filter region therein configured to substantially block incident radiation thereon substantially only of said first wavelength while substantially allowing other visible wavelengths to be transmitted; —selecting a bandwidth corresponding to a first predetermined wavelength band including said first wavelength and exposing said polymeric film (320) to radiation from one or more further laser sources of respective different wavelengths within said first predetermined wavelength band to create a notch filter region therein, including said first filter region, said notch filter region being configured to substantially block incident radiation thereon at a wavelength within said first predetermined wave

Abstract: A method of forming a conformable filter for a vehicle window, comprising the steps of: —selecting at least a first wavelength corresponding to a predetermined laser threat; —providing a conformable photosensitive film and exposing said film to radiation from a focused laser source of said first wavelength to create a first filter region therein configured to substantially block incident radiation thereon substantially only of said first wavelength; —determining if an essential lighting source outside or inside the vehicle includes said first wavelength and, if so, —selecting a bandwidth corresponding to a first predetermined wavelength band including said first wavelength and exposing said polymeric film to radiation from one or more further laser sources of respective different wavelengths within said first predetermined wavelength band to create a notch filter region therein, including said first filter region, said notch filter region being configured to substantially block incident radiation thereon at w

Abstract: There is disclosed a filter for a vehicle window comprising a layer of filter material, the layer of filter material being for substantially preventing the transmission of radiation at a first predetermined visible wavelength band, the first predetermined visible wavelength band covering the wavelength of a predetermined laser threat, whilst substantially allowing visible wavelengths outside of the band to be transmitted, such that the filter can offer a visible light transmission of at least 70%, and a radiation detector, such that radiation at the first predetermined wavelength band can be detected.

Abstract: The following invention relates to an optical device for use in a system that requires optical zoom or focus abilities, particularly for providing pre-set zoom parameters with a very low energy requirement. There is provided an optical magnification device comprising at least one pair of optically aligned deformable reflectors, wherein each reflector pair has at least two configurations, wherein selection of a first and a second configuration of said deformable reflector pairs provides pre-defined magnification states, such that in any configuration one reflector is substantially concave and the other is substantially convex; at least one controller may cause both the reflectors to move between said at least two configurations.

Abstract: There is disclosed a directional multi-band antenna comprising: a primary reflector, at least one secondary reflector, a multi-layer dielectric layer selectively reflective or transmissive of incident radiation according to wavelength, the layer being provided at the surface of either the primary or the secondary reflector, an RF unit comprising a collocated sensor and transmitter, an Optical unit comprising a collocated sensor and transmitter, arranged such that the primary reflector is for passing signals between the secondary reflector and the environment, the secondary reflector is firstly for passing signals between the primary reflector and the RF unit, and secondly for passing signals between the primary reflector and the Optical unit and arranged such that the antenna is operable to transmit or receive, RF or Optical signals, along a common beam axis.

Abstract: There is disclosed A directional multi-band antenna, the antenna comprising: —an optical unit comprising an optical sensor; —an RF unit comprising an RF sensor; —a substantially planar optical lens, the optical lens comprising surface relief elements for beam forming, the lens being arranged to focus optical signal beams, incident along a first optical axis, onto the optical sensor, the optical lens being substantially transparent to RF signals, —an RF beam forming device arranged to receive RF signals incident along the first optical axis and focus such RF signals onto the RF sensor.

Abstract: The following invention relates to an improved LCD Backlight, particularly to an improved arrangement of the optical scattering dots within the light guiding plate. The light guiding plate comprises a lower surface which is formed with a plurality of optical scattering dots, which scatter and reflect the light beams to convert the light beams into a uniform surface light source, characterised wherein the surface area of each optical dot decreases as a function of its distance from at least one of the three edges comprising the LED lights.

Abstract: A beamsplitter is disclosed for splitting an input beam of radiation which is incident upon the beamsplitter into at least one first and second output beam of radiation which propagate from the beamsplitter.

Abstract: There is disclosed a directional multi-band antenna comprising a substrate structure, a plurality of RF units arranged at the substrate structure to provide an RF phased array, the RF phased array having an angular scan range, an array of optical units arranged at the substrate structure and interspersed amongst the RF units, an array of optical lensing devices supported over the substrate structure, the array of optical lensing devices being substantially RF transmissive and being arranged to correspond with the arrangement of the optical units, such that each optical unit may communicate light signals with an associated optical lensing device so as to communicate light signals along an optical axis within the angular scan range of the RF phased array.

Abstract: There is disclosed a spectral imaging apparatus for processing electromagnetic (EM) radiation, the EM radiation originating from a target scene and comprising a wide range of frequencies, the system comprising: A dispersive element for receiving EM radiation from the target scene and promoting differing amounts of dispersion depending on the frequency of the EM radiation, A deformable lens arranged to receive EM radiation from the dispersive element, An imaging sensor for detecting EM radiation across the wide range of frequencies, and arranged to receive EM radiation from the deformable lens, Wherein the deformable lens is operable to adopt any one of a plurality of focal conditions, each focal condition tending to focus a different range of the EM radiation at the imaging sensor, each focal condition thereby defining a component band for the EM radiation.