ИСТИНА

In our work we investigate both theoretically and experimentally the spectral and spatial properties of bright squeezed vacuum light and suggest methods to control and manipulate its characteristic features, photon correlations and mode content using a developed SU(1,1) nonlinear interferometer scheme based on two nonlinear crystals separated by a certain medium. The scheme has turned out to be a versatile source of OAM modes populated by large numbers of photons. Variation of the number of OAM modes is demonstrated by changing the distance between the crystals or the pump power. The reconstruction of the spatial Schmidt modes shapes and weights from the covariance measurement on single-shot spectra is reported. Methods of selective amplification of different radial modes are developed. In addition, Methods of production of mostly single frequency mode radiation or selective generation of extremely narrow two-color squeezed vacuum light are suggested theoretically and demonstrated experimentally. A very good agreement between our theoretical results and experimental data is demonstrated.