Laguerre-Gaussian modes generated vector beam via nonlinear magneto-optical rotation

Abstract

Laguerre-Gaussian (LG) beams contain a helical phase front with a doughnut-like intensity profile. We use the LG beam to introduce a rather simple method for generation of a vector beam (VB), a beam with spatially-dependent polarization in the beam cross section, via the nonlinear magneto-optical rotation (NMOR). We consider the NMOR of the polarization of a linearly polarized probe field passing through an inverted Y-type four-level quantum system interacting with a LG control field and a static magnetic field. It is shown that the polarization of the transmitted field is spatially distributed by the orbital angular momentum (OAM) of the LG control field, leading to generation of the VB with azimuthally symmetric polarization distribution. We show that the polarization and intensity distributions of the VB spatially vary by changing the OAMs of the LG control field. Moreover, the radial index of the LG control field has a major role in more spatially polarization distributing of the VB. It is shown that the intensity of the generated VBs in different points of the beam cross section can be controlled by the OAM as well as the radial index of the LG control field. However, the VB with highly spatially distributed can be generated for higher values of the radial index of LG control field. The analytical calculations determine the contribution of the different nonlinear (cross-Kerr effect) phenomena on the generation of the VB. We show that the VB is mainly generated via birefringence induced by the applied fields. Finally, we use asymmetric LG (aLG) beams for making the VBs with asymmetric polarization distribution. It is shown that by applying aLG beams, the azimuthal symmetry of the polarization distribution breaks and the asymmetric polarization distribution can be controlled by OAM and radial index of the aLG control field. The obtained results may find more interesting applications in fiber/free space optical communication to enhance the capacity of the information transmission.

Interaction of four level closed loop atomic systems in the presence of two vector beams

“…A recent numerical study shows that LG modes can enhance microwave electric field sensing capability [13]. Ghaderi et al [14] studied theoretically the generation of vector beams from LG modes of light through nonlinear magneto-optical rotation.…”

A Fourier-invariant squared Laguerre-Gaussian vortex beam

“…Так, например, в одной из своих работ авторы этой статьи предложили семейство асимметричных лазерных пучков ЛГ [35], а в работе [36] другая научная группа представила метод генерации таких пучков высокой мощности. Авторы работы [37], используя моды ЛГ, продемонстрировали возможность генерации векторного пучка с пространственно-зависимой поляризацией в поперечном сечении посредством нелинейного магнитооптического вращения. Новый класс составных вихревых пучков, получаемый путем коаксиального наложения пучков ЛГ с одинаковыми параметрами (расстояние и радиус) перетяжки, был представлен в [38].…”

Product of Two Laguerre–Gaussian Beams

“…A family of asymmetric LG laser beams has been discussed [17], and a technique for generating high-power asymmetric LG beams has been proposed [18]. Using the LG beams, a vector beam with space dependent transverse polarization has been generated by a method of nonlinear magneto-optic rotation [19]. A new class of composite vortex beams generated by coaxially superimposing LG beams Photonics 2022, 9, 496 2 of 9 with identical waist location and parameters has been proposed [20].…”