Pattern manipulation via on-chip phase modulation between orbital angular momentum beams

Abstract

An integrated approach to thermal modulation of relative phase between two optical vortices with opposite chirality has been demonstrated on a silicon-on-insulator substrate. The device consists of a silicon-integrated optical vortex emitter and a phase controlled 3 dB coupler. The relative phase between two optical vortices can be actively modulated on chip by applying a voltage on the integrated heater. The phase shift is shown to be linearly proportional to applied electrical power, and the rotation angle of the interference pattern is observed to be inversely proportional to topological charge. This scheme can be used in lab-on-chip, communications and sensing applications. It can be intentionally implemented with other modulation elements to achieve more complicated applications.

Generation of photonic orbital angular momentum superposition states using vortex beam emitters with superimposed gratings

“…It should be noted that the number of the superimposed OAM states will be limited by the fabrication resolution of electron beam lithography, although in theory there is no upper limit. Compared to the previous works [10,11], the integrated device demonstrated in this manuscript is more compact as it does not require the assistance of other integrated components, like 3dB couplers or MZIs. Moreover, the current device have the potential of generating superposition states of more than 2 dimensions by simply putting more gratings, while the previous devices can only generate 2 dimensional superposition states.…”

“…The electrical detuning also enabled on-off keying OAM modes at record rates of ~15 μs [9]. An functional PIC composed of an OAM emitter and a 3dB coupler that can be used to generate and manipulate OAM superposition states was also reported [10], in which the input light simultaneously excited the clockwise and anticlockwise WGMs in the micro-ring resonator and thereby generated two OAM states with equal but opposite topological charge. The relative phase between the two OAM states could be actively modulated by a phase shifter integrated with the input waveguide.…”

Tailoring OAM spectrum of high-order harmonic generation driven by two mixed Laguerre–Gaussian beams with nonzero radial nodes

“…With a wide OAM spectrum, the vortex beam can be used in the ultrasensitive angular measurement, [25] the generation of arbitrary su-perpositions of atomic rotational states in a Bose-Einstein condensate, [26] the measurement of object parameters, [27] the performance of rotations and reflections on images, [28] and so on. To generate OAM spectra in the infrared (IR) and visible spectral ranges, there are several methods available including computer-generated holograms on the spatial light modulators, [29] specially designed metasurfaces, [30] integrated angular momentum gratings, [31,32] and coherent mixing of pre-generated vortex beams. [33] However, using optical elements is difficult to generate and tailor the OAM spectrum of light in the extreme ultraviolet (XUV) or soft x-rays.…”

Metasurfaces for Amplitude-Tunable Superposition of Plasmonic Orbital Angular Momentum States

“…In addition, a variety of relative amplitudes of two vortex beams are involved in superposition and can serve as a carrier of information in wireless communications [21]. Various tools have been established to produce superposed OAM models, such as q plates [22], cylindrical lenses [23], spiral phase plates [24], computergenerated holograms [16], spatial light modulators [25], and inhomogeneous birefringent elements [26]. Recently, multifunctional metasurfaces have provided an alternative strategy for manipulating the superposition of vortex beams, leading to the development of miniaturization and multifunctional metasurface devices.…”