Patent ID: 7535617

Claim:
An acousto-optical tunable filter (AOTF) device comprising birefringnent crystal cells in a non-collinear double AO crystal cell design, each cell has a transducer attached, the transducer in turn is configurably attached to a radio-frequency (RF) acoustic signal source to enable AO tunable filtering within each cell device at a desired tuned-frequency of operation, the transducers are positioned so as to provide an in-line single diffracted beam from un-polarized incident radiation coming through a combination two beam forming lenses, between the two crystal cells, an optical aperture member is attached to the cell device so as to let only collimated diffracted radiation pass through the first crystal and an un-diffracted beam is blocked by the optical aperture whereby this diffracted radiation with polarization normal to a given plane goes through a second diffraction when passing through the second AO crystal cell whose orientation is opposite of the first crystal, and the second crystal cell diffracts the radiation such that polarization of the doubly diffracted beam is normal to the given plane and perpendicular to a direction of radiation propagation and egress from the device.