Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J4/00—Measuring polarisation of light
  • G01J4/04—Polarimeters using electric detection means
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/03—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect
  • G02F1/055—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect the active material being a ceramic
  • G02F1/0551—Constructional details
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F2203/00—Function characteristic
  • G02F2203/12—Function characteristic spatial light modulator
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F2203/00—Function characteristic
  • G02F2203/50—Phase-only modulation

Definitions

• a standard device programmable waveguide and fixed analyzer then sequentially performs the n combinations of analyzes required.
• the programmable waveguide function is performed by mechanical rotation of a wave plate or by means of a polarization controller based on liquid crystals (P.CIémenceau, S. Breugnot, L. Collot, "Apparatus for Polarimetric Imaging, Patent 2,769,980 (1997)).
• P.CIémenceau, S. Breugnot, L. Collot "Apparatus for Polarimetric Imaging, Patent 2,769,980 (1997).
• response time 10 to 100ms for the nematic liquid crystals
• the response time of the component is also significantly important in the case where the system must be mounted on a mobile platform (drone type, with travel speeds of the order of 50km / h).
• the focal length f of the first lens corresponds to the following equation: where O h m is the angular acceptance of the programmable waveplate and at the surface defined by the intersection of the half-angle cone at the vertex ⁇
• the polarimetric imaging system comprises at least:
• these materials have a broad transmission band (transparent from 500 nm to 7000 nm (G. Haertiing, CE Land, "Hot-pressed (Pb, La) (Zr, Ti) O 3 ferroelectric ceramics for electrooptic applications", J.
• FIG. 10 illustrates a detailed view of the programmable waveguide array in the third variant of a polarimetric imaging system according to the invention.
• the first variant of a polarimetric imaging system comprises an objective 32, a programmable waveguide 33, a detection means 35 and a polarizer 34 located between said programmable waveguide and said detection means 35.
• the polarizer projects the polarization along its (fixed) axis.
• the combination of the waveguide and polarizer allows projection of the polarization along any axis.
• the system measures the state of polarization of the light backscattered by an object 31, illuminated by a light source.
• the programmable wave plate 33 comprises in particular a block of a material with an isotropic electro-optical tensor, and comprising a set of at least three electrodes. An exemplary embodiment of such a programmable waveguide is illustrated in FIG. 4.
• the programmable waveguide 33 is in the form of a block of parallelepipedic electro-optical material 45 on whose edges there are four electrodes E, referenced 44, 41, 42 and 43 in FIG.
• the electrodes 61, 62, 63 and 64 are formed by through holes, substantially cylindrical and metallized, pierced in the thickness of the material with an isotropic electro-optical tensor.
• the electrodes 61, 62, 63 and 64 are made in the volume of the material to optimize on the one hand the overlap between the optical wave and the applied electric field and, on the other hand, the homogeneity of the applied electric field. This has the effect of optimizing the effectiveness of the component.
• the pixels of the matrix are collectively controlled, a possible variation of pixel pixel characteristics that can be corrected to the calibration processing.
• the generated electric fields are opposite for two adjacent pixels. This does not influence the operation of the device since the electro-optical effect used is quadratic, therefore independent of the polarity of the electric field. It is also possible to envisage an individual addressing of each pixel.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Nonlinear Science (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Crystallography & Structural Chemistry (AREA)
• Optics & Photonics (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)

Applications Claiming Priority (2)

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• 2006
  • 2006-10-20 FR FR0609230A patent/FR2907547B1/fr not_active Expired - Fee Related
• 2007
  • 2007-10-16 US US12/445,991 patent/US20100039646A1/en not_active Abandoned
  • 2007-10-16 WO PCT/EP2007/061014 patent/WO2008046820A1/fr not_active Ceased
  • 2007-10-16 EP EP07821380A patent/EP2092282A1/de not_active Withdrawn

Non-Patent Citations (1)

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