Method of Generating Spatial Bell States

Invention relates to controlling intensity, colour, phase, polarisation or direction of light. In the method, the angular spectrum of the generated optical two-photon radiation is varied according to the spatial profile of variation of intensity of laser pumping. The key feature of the method is the use of laser pumping in high spatial modes in rigid focusing mode. The method is based on adaptive adjustment of the phase front of laser pumping using an active spatial light phase modulator. This adjusted front, owing to phase synchronism conditions in the nonlinear crystal, generates a biphoton amplitude shape corresponding to a spatial Bell state.