Abstract

Bessel light beams (BLB) are widely used in nonlinear optics especially for nonlinear harmonic generation. At the same time being specially periodic by there nature BLB cause periodic modulation of optical properties of nonlinear medium and thus create necessary condition for self-diffraction effect. In the paper are presented the results of experimental and theoretical investigation BLB selfdiffraction in heavily doped n-InP in the spectral range below the band edge. The experiments have been performed with axicons with conicity angle of ~0.5° and 3°. In general the diffraction pattern has rather complicated structure with fine features. The example of diffracted light intensity distribution in the far field is shown in the Fig. In all the experiments one can observe an additional diffraction ring at an angle corresponding to the triple axicon conicity angle. The intensity of this ring is higher for the axicon with conicity angle of 3°. It was found also that at certain experimental conditions gaussian like central maximum can appear in diffraction pattern.

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