Dynamic optical reflector and interrogation system
AssigneeQinetiq Limited
InventorsAndrew Scott, Keith Lewis, Mark McNie, Kevin Brunson, David Jackson, Kevin Ridley
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Abstract
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.
Claims20
A modulator for modulating an optical signal, the modulator comprising a spacing-controllable etalon and a retro-reflector arranged to retro-reflect light received via the etalon back through the etalon.
An optical detector arrangement comprising a plurality of photo-detectors with associated means for restricting the light acceptance angle, the means being so arranged as to allow determination, based on outputs from the photo-detectors, of a direction of incidence of light from a remote source.
An optical interrogator for use with a reflective optical tag, the interrogator comprising a laser source of light at two distinct wavelengths which are reflected by the tag substantially in anti-phase one with the other.
18-20. (canceled)
A reflective tag comprising an etalon and a retro-reflector arranged to retro-reflect light received via the etalon back through the etalon.
Dependencies are inferred from the claim text.