Propagation of transverse photonic orbital angular momentum through few-mode fiber

Spatiotemporal optical vortex(STOV)pulses can carry transverse orbital angular momentum(OAM)that is perpendicular to the direction of pulse propagation.For a STOV pulse,its spatiotemporal profile can be significantly distorted due to unbalanced dispersive and diffractive phases.This may limit its use in many research applications,where a long interaction length and a tight confinement of the pulse are needed.The first demonstration of STOV pulse propagation through a few-mode optical fiber is presented.Both numerical and experimental analysis on the propagation of STOV pulse through a commercially available SMF-28 standard telecommunication fiber is performed.The spatiotemporal phase feature of the pulse can be well kept after the pulse propagates a few-meter length through the fiber even with bending.Further propagation of the pulse will result in a breakup of its spatiotemporal spiral phase structure due to an excessive amount of modal group delay dispersion.The stable and robust transmission of transverse photonic OAM through optical fiber may open new opportunities for transverse photonic OAM studies in telecommunications,OAM lasers,and nonlinear fiber-optical research.

Efficiency enhancement for the orbital angular momentum photon quantum interface via single photon frequency upconversion

As the application of orbital angular momentum(OAM) of photon quantum in quantum communication, the OAM photon quantum interface for the transmission wavelength from the telecom communication quantum information storage in visible regime is required. Here we demonstrate the efficiency enhancement for the OAM photon quantum interface based on the frequency upconversion from telecom wavelength to visible regime by sum-frequency generation. The infrared photons at 1 558 nm carrying different OAM values could be converted to the visible regime at 622.2 nm with the optimal efficiency via adjusting the pump beam waist radius and intensity.

Spatiotemporal optical vortex wavepackets with phase singularities embedded in multiple domains[Invited]

Spatiotemporal optical vortex(STOV)wavepacket carrying transverse photonic orbital angular momentum(OAM)has been extensively studied in the past few years.In this Letter,we propose and study a novel STOV wavepacket with multiple phase singularities embedded in different space–time domains using analytical and numerical approaches.By tuning different parameters used for designing the wavepacket,it is possible to engineer both the magnitude and orientation of the photonic OAM in space–time.The vectorially controllable OAM will pave new avenues and facilitate applications such as novel optical communication,studying complicated quantum systems,and spin-and-OAM interactions.