ИСТИНА

The main objective of the work relates to investigation of mode structure of the thermal light beam. We apply recently developed technique for selecting Schmidt modes in angular spectrum of biphoton field [1] to quasi-thermal light. Usual Hanbury Brown and Twiss scheme is used for revealing intensity correlations of the quasi-thermal source (rotating ground disk). After proper preparation of the thermal light beam by means of appropriate lenses and appertures we introduce the spatial light modulator (SLM) followed by single-mode fiber in one arm of intensity interferometer followed by single-mode fiber. The other channel of the interferometer is supplied with single-mode fiber which might be scanned in the transverse direction(s). Switching by SLM between different Hermite-Gauss modes we check the angular correlation function in the fourth order in the field. The preliminary results show that there is no correlations ( ) between orthogonal Hermite-Gauss modes while choosing the same modes the corresponding meaning reaches its maximal value . [1] S. S. Straupe, D. P. Ivanov, A. A. Kalinkin, I. B. Bobrov, S.P.Kulik, Angular Schmidt modes in spontaneous parametric down-conversion. Phys. Rev. A, 83(6), 060302(R) (2011).