High speed switching between arbitrary spatial light profiles

Abstract

Complex images, inscribed into the spatial profile of a laser beam or even a single photon, offer a highly efficient method of data encoding. Here we present a prototype system which can quickly modulate between arbitrary images. We display an array of holograms, each defined by its phase and intensity profile, on a spatial light modulator. The input beam is then steered by an acousto-optic modulator to one of these holograms, where it is converted into the desired light mode. We demonstrate switching between characters within three separate alphabets at a switching rate of up to10 kHz. This rate is limited by our detection system, and we anticipate that the system is capable of far higher rates. Furthermore our system is not limited in efficiency by channel number, making it ideal for quantum communication applications.

Fast Generation and Detection of Spatial Modes of Light using an Acousto-Optic Modulator

“…A similar approach to the present work has been taken by Radwell et al, demonstrating high-speed switching between arbitrary spatial patterns of light [15]. However, this earlier work only demonstrated mode generation at a speed of 10 kHz, which is potentially attainable with fast DMDs.…”

“…In contrast, we observe switching rates for mode generation of up to 500 kHz, well in excess of any existing SLM or DMD technology. Furthermore, while the modes generated in [15] were only characterized qualitatively through intensity measurements, we verify the phase structure of our generated modes quantitatively using a second hologram. In addition, we show that operating the setup in reverse allows for fast mode measurement, instead of fast mode generation.…”

Topological photonic orbital-angular-momentum switch

“…Conventional spatial light modulator [23] and digital micro-mirror device [24] are limited by the switching rates of ∼kHz. Higher switching rates can be achieved by combing acousto-optic (electro-optic) modulator with SLMs (q-plate) [25,28], or using on-chip resonators [26]. However, the acousto-optic modulator would induce unwanted change in wavelength, and the on-chip switching has a very low efficiency.…”

Quantum Information with Structured Light

“…However, to generate the states in the ANG basis one would need to modulate both the amplitude and phase of the beam, a task that best suits free-space holography. Recently, a method involving static holograms realized on an SLM and an AOM for switching between them achieved a MHz mode-switching rate [108]. Unfortunately, the change in the wavelength caused by the AOM forbids applying this method for QKS since side-channel attacks could be performed based on spectrum.…”