Abstract: An acousto-optic tunable filter, for laser tuning, comprises an acoustic transducer connected to one face of an anisotropic crystal or Bragg cell which is cut at such an angle relative to its optic axis that an acoustic wave projected into the crystal normal to the face causes wavelength-specific diffraction of an incident optic wave (from a laser amplifying element) which nearly, but not completely, satisfies the parallel-tangents phase matching condition, thus preserving a substantial angular field of view, the angle also being such that the diffraction is polarization-insensitive.