The controversial term “nondiffracting beam” was introduced into optics by Durnin in 1987. Discussions related to that term revived interest in problems of the light diffraction and resulted in an appearance of the new research direction of the classical optics, dealing with the localized transfer of electromagnetic energy. In this paper, the physical concept of the nondiffracting propagation is presented and the basic properties of the nondiffracting beams are reviewed. Attention is also focused to the experimental realization and to applications of the nondiffracting beams.

Nondiffracting optical beams: physical properties, experiments, and applications

“Non-diffracting” beams do not spread as they propagate. This property is useful in many areas. Here, the theory, generation, properties, and applications of various “non-diffracting” beams, including the Bessel beam, Mathieu beam, and Airy beam is reviewed. Applications include imaging, micromanipulation, nonlinear optics, and optical transfection.

Light beats the spread: ``non-diffracting'' beams

We study the horizontal transport of ultracold atoms over macroscopic distances of up to 20 cm with a moving 1D optical lattice. By using an optical Bessel beam to form the optical lattice, we can achieve nearly homogeneous trapping conditions over the full transport length, which is crucial in order to hold the atoms against gravity for such a wide range. Fast transport velocities of up to 6 m s−1 (corresponding to about 1100 photon recoils) and accelerations of up to 2600 m s−2 are reached. Even at high velocities the momentum of the atoms is precisely defined with an uncertainty of less than one photon recoil. This allows for construction of an atom catapult with high kinetic energy resolution, which might have applications in novel collision experiments.

https://www.uni-ulm.de/fileadmin/website_uni_ulm/nawi.inst.235/Forschung/Diplomarbeiten/Diploma_Thesis_Stefan_Schmid_2006.pdf

Long distance transport of ultracold atoms using a 1D optical lattice

A beam that resembles a Bessel beam on two scales is generated using a tunable acoustic gradient index of refraction (TAG) lens. The minor scale of the TAG-generated Bessel beam is nondiffracting and self-healing. The major scale of the beam diffracts while still forming a Bessel pattern due to the specific geometry of the TAG lens. The acoustic and optical theory behind the TAG lens is outlined, and the experimental beam itself is presented. The major and minor rings are explained, and the TAG beam is compared with both axicon-generated and conventionally focused Gaussian beams.

Multiscale Bessel beams generated by a tunable acoustic gradient index of refraction lens.

Self-action of Bessel beam in nonlinear medium

We show that the transmission of a periodic grating with circular symmetry can be composed of the sum of the transmissions of positive and negative axicons of different orders. The properties of the light beams generated by the gratings can be understood from the well-known properties of the light beam of an axicon, which is approximately a Bessel beam of zeroth order. The method is applied to a circular binary phase grating, which is investigated both theoretically and experimentally in the spatial domain and the Fourier domain. A simple and accurate method for determining the focal length of a lens with use of Bessel light beams is presented.

Properties of Bessel beams generated by periodic gratings of circular symmetry

Stimulated Raman scattering in H 2 gas was studied with a Bessel pump beam, which was generated with a binary phase grating. The first Stokes light was emitted along the surface of a cone, the angle of which was equal to the cone angle of the Bessel pump beam multiplied by the ratio of the wavelengths of the Stokes and pump beams. High conversion efficiency into the first Stokes light of as much as 60% was achieved, indicating that the complete Bessel J0 mode of the pump beam is involved in the stimulated scattering process.

L. Niggl

Papers

Properties of Bessel beams generated by periodic gratings of circular symmetry

Efficient conical emission of stimulated Raman Stokes light generated by a Bessel pump beam.

Gain-guided modes in stimulated scattering processes with diffraction-free pump beams

Nonplanar phase-matching of stimulated anti-Stokes Raman scattering pumped by a Bessel beam

Gain guiding in stimulated scattering processes with hollow Bessel pump beams