Talbot effect on orbital angular momentum beams: azimuthal intensity repetition-rate multiplication

Abstract

We propose and experimentally demonstrate the azimuthal Talbot effect on orbital angular momentum (OAM) beams. By applying predetermined phases to a number of OAM beams carrying different topological charges, the intensity petal is self-imaged in the azimuthal angle, with arbitrary azimuthal repetition-rate multiplication. The close analogy between temporal and azimuthal Talbot self-imaging is studied. In addition, the effect of amplitude apodization of the OAM spectrum on the resulting intensity pattern, and the azimuthal Talbot effect on Laguerre-Gaussian beams of the same radial indices, are experimentally investigated. All of our experimental images are in excellent agreement with simulation results.

Azimuthal beam shaping in orbital angular momentum basis

“…Based on the Talbot self-imaging effect in azimuth, the azimuthal beam shaper can act as a beam splitter or combiner. The azimuthal Talbot effect suggests that when a beam is modulated with Talbot phase on its OAM mode spectrum, the intensity of the beam would be self-imaged in the azimuth, with arbitrary azimuthal repetition-rate multiplication 17 . As shown in Fig.…”

“…The azimuthal Talbot effect suggests that when a beam is modulated with Talbot phase on its OAM mode spectrum, the intensity of the beam would be self-imaged in the azimuth, with arbitrary azimuthal repetition-rate multiplication. 17 (see Note 1.2 in the Supplementary Material), the beam undergoes self-imaging and is split into two or three beams in azimuth, respectively. The input beam is the same as that in Fig.…”

“…Various methods have been proposed to generate arbitrary OAM mode spectra, and almost all of them are implemented by modulating the optical field at the generation stage 16 – 18 Apart from generation, the ability to externally shape a given OAM field is also highly desired, for example, when routing mode channels in an OAM-based communication system. This requires the manipulation of an optical field in its OAM spectrum; however, only a few demonstrations show the multiplication of the OAM mode orders 19 , 20 or the selective filtering of the OAM modes 21 , 22 .…”

Effects of mitigation of pixel cross-talk in the encoding of complex fields using the double-phase method

“…20 Here, we deal with a particular interferometric method 21 aimed at encoding and retrieving the complex field of coherent laser beams. This method has been widely and successfully employed in several experimental tasks, including but not limited to demonstrating the Talbot selfimaging in the azimuthal angle, 22 generating speckleless holographic displays, 23 trapping magnetic microparticles employing Bessel-Gauss beams, 24 shaping optical vector beams, 25 or experimentally investigating the propagation and focusing characteristics of Airy beams. 26,27 In all of these applications, the implementation of the above-mentioned encoding method 21 was carried out with the help of a commercially available PA-LCoS SLM.…”

Complex spatial shaping of femtosecond pulses with phase-only spatial light modulators

“…Double phase methods has been successfully used for different applications including generation of speckleless holographic displays [111], optical trapping of micro-particles by generating controllable light capsules [112], demonstrate the Talbot self-imaging in the azimuthal angle [113], shaping threedimensional vector beams with arbitrary intensity distribution and controllable polarization [114], and generation of specifically designed Airy beams like elliptical Airy beams [115] or multifocus autofocusing Airy beams [116].…”