On-chip generation of the reconfigurable orbital angular momentum with high order

Abstract

In this manuscript, the generation of an optical vortex beam with high order and reconfigurable orbital angular momentum (OAM) is studied. Multi-waveguide holographic gratings (MWHG) are deployed to generate OAM beams with high order. The generation of the OAM beam with an order l from +4 to +8 is demonstrated by numerical simulations, and the generated OAM order is manipulable and configurable by incident phase. The working bandwidths of the MWHG for different OAM orders are at the level of 40 nm. This work could provide valuable references for practical implementation of OAM in integrated optics.

Recent Advances in Generation and Detection of Orbital Angular Momentum Optical Beams—A Review

“…Figure 10c shows a SEM image of the first-order SPP that will be inserted into the circular aperture in the Cr/Au layer of the MEMS DBR. Notwithstanding that most of the proposed methods are experimentally verified, telecom applications are demonstrated only for ring resonators with annular grating [61,148,150], fixed SPPs [65,159,160], and lately for a pixel-array structure [154]. The output OAM beam from most out-of-plane generation methods is satisfactory in terms of mode purity; nevertheless, free-space propagation necessitates the use of a lens to concentrate the signal and couple it into the optical fiber, which reduces the final device's reliability and scale.…”

“…In [ 148 ] optical OV beam with a well-defined and continuously tunable OAM state is generated using the silicon bus WG that forms an open circle. A multi-WG surface holographic gratings composed of four WGs perpendicular to each other with holographic gratings etched on their surfaces is proposed in [ 61 ] for high-order OAM generation up to l = +8. In [ 152 , 153 ], the free space OV beam and the in-plane guiding wave can be transferred to each other by placing a holographic grating on top of a dielectric WG.…”

“… Methods to generate light with OAM: ( a ) Shift in the OAM order by illuminating a 3D element with the laser light of different wavelengths [ 58 ]; ( b ) OAM generator via CGH [ 59 ]; ( c ) Schematic of the OV beam generator from MS [ 60 ]; and ( d ) The schematic illustration of the OV beam generator on the embedded multi-WG [ 61 ]. …”

“…Figure 2 demonstrates four different methods used for the creation of light with OAM which are widely used among the researchers [ 58 , 59 , 60 , 61 ]. Another device, comprising a mutable amplitude splitter (VAS) and an OAM emitter, has recently been suggested, in which the comparative amplitude of the two OAM states with inverse chirality can be tuned [ 62 ].…”

Multi-grating design for integrated single-atom trapping, manipulation, and readout

“…A lot of effort has been dedicated to the quantum information processing based on cold atoms [4][5][6] and photons [7,8]. Recently, the photonic integrated chips have been widely applied in the quantum information science and show great potentials in extending the photonic quantum information processors to tens of qubits [9][10][11][12]. In contrast, most previous investigations of cold atoms are implemented with conventional optical setup, which is cumbersome, sensitive to environment perturbations, and costly.…”