Abstract
Orbital angular momentum (OAM) beams may create a new paradigm for the future classical and quantum communication systems. A majority of existing OAM beam converters are bulky, slow, and cannot withstand high powers. Here, we design and experimentally demonstrate an ultra-fast, compact chalcogenide-based all-dielectric metasurface beam converter which has the ability to transform a Hermite–Gaussian (HG) beam into a beam carrying an OAM at near infrared wavelength. Depending on the input beam intensity, the topological charge carried by the output OAM beam can be switched between positive and negative. The device provides high transmission efficiency and is fabricated by a standard electron beam lithography. Arsenic trisulfide (As 2 S 3 ) chalcogenide glass (ChG) offers ultra-fast and large third-order nonlinearity as well as a low two-photon absorption coefficient in the near infrared spectral range.
Highlights
Structured light and, in particular, beams carrying orbital angular momentum (OAM) have been shown to enable and expand a plethora of photonic applications from optical trapping and manipulation, to astronomy and light filamentation [1]
We describe a nonlinear metasurface with the capability of switching between two opposite topological charges of OAM beams depending the intensity of the input beam
The input HG beam was transmitted through the metasurface and the resulting phase distribution directly after the metasurface is given by φ = ( N − 1)90◦, where N
Summary
Structured light and, in particular, beams carrying orbital angular momentum (OAM) have been shown to enable and expand a plethora of photonic applications from optical trapping and manipulation, to astronomy and light filamentation [1]. The OAM of light can be used as an alternate degree of freedom for expanding the capacity of communication channels [2–6]. Many of these systems require the development of dynamically reconfigurable and high-power OAM beams. An SPP is only suitable to generate an OAM beam with fixed topological charge for a designed wavelength. SLMs, dynamically controlled by computers, are able to generate tunable OAM beams with high intensities [8] but are limited by their resolution, bulky dimensions, and the switching speed. For nonlinear applications requiring dynamically changing topological charge of light together with high intensities [9], a tunable OAM metasurface-beam converter may enable new opportunities.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
