Diffraction-free, self-reconstructing Bessel beam generation using thermal nonlinear optical effect

Abstract

We propose a method to generate a Bessel beam using cross-phase modulation based on the thermal nonlinear optical effect. The thermal nonlinear medium is shown to have the ability to vary a Gaussian beam (probe beam) into a hollow beam when the medium is illuminated with a counter-propagating Gaussian beam (pump beam). It is demonstrated that this method has no restriction to the probe beam wavelength. Moreover, the generated Bessel beam exhibits superior non-diffraction properties during propagation and self-healing after encountering an obstruction on the beam path. The parameters of the beam can be easily adjusted by both the pump beam power and the sample concentration. The merits of variable parameters, no requirement for input beam wavelengths, simple setup, and low-cost would make this method significant in a variety of applications, especially in those areas where the parameters of the Bessel beam need to be easily adjusted without changing the setup.

Enhancement of the phase conjugation degenerate four-wave mixing using the Bessel beam

“…The Bessel beam can be obtained in the focusing range of the hollow beam. The Bessel beam generation using such a method based on the cross-phase modulation based on the thermal nonlinear effect has been well characterized in our recent published paper [23]. The probe beam can be switched between a Gaussian and a hollow beam simply by blocking the intense beam E in or not.…”

“…The output E w from the cuvette with ethanol is reflected by PBS4, collimated by a telescope system (Lens2 and Lens3), and then employed as the probe field E p ω; k p . The output E w from the cuvette with ethanol can be switched between Gaussian beam and hollow beam by setting the beam E in off or on [23]. By focusing the hollow beam (Lens5), we can obtain a Bessel beam in the focusing range [27].…”

“…where n 0 is the linear refractive index, I in is the intensity of the intense beam, and n 2 is the nonlinear refractive coefficient caused by thermal nonlinear effect, expressed as [23]…”

“…In this work, we use a Bessel beam as the probe beam and study the enhancement of DFWM in hot atomic Rb vapor. The Bessel beam is generated by focusing the hollow beam generated using cross-phase modulation based on the thermal nonlinear optical effect [23]. Compared with commonly used hollow beam generation methods (including axicon lenses [24] and spatial light modulators [25]), the method employed in this work has the advantages of tunable size and no limitation of the input power.…”

On nabla discrete fractional calculus operator for a modified Bessel equation

“…Semiclassical dynamics of dilute thermal atom clouds located in 3-D optical lattices generated by stationary optical Bessel beams were characterized [20]. A method to generate a Bessel beam using cross-phase modulation based on the thermal non-linear optical effect was introduced [21]. The expansions of the modified Bessel functions were used to obtain the temperature field [22].…”