Optical Skyrmions have many important properties that make them ideal units for high-density data applications, including the ability to carry digital information through a discrete topological number and the independence of spatially varying polarization to other dimensions. More importantly, the topological nature of the optical Skyrmion heuristically suggests a strong degree of robustness to perturbations, which is crucial for reliably carrying information in noisy environments. However, the study of the topological robustness of optical Skyrmions is still in its infancy. Here, we quantify this robustness precisely by proving that the topological nature of the Skyrmion arises from its structure on the boundary and, by duality, is resilient to spatially varying perturbations provided they respect the relevant boundary conditions of the unperturbed Skyrmion. We then present experimental evidence validating this robustness in the context of paraxial Skyrmion beams against complex polarization aberrations. Our work provides a framework for handling various perturbations of Skyrmion fields and offers guarantees of robustness in a general sense. This, in turn, has implications for applications of the Skyrmion where their topological nature is exploited explicitly, and, in particular, provides an underpinning for the use of optical Skyrmions in communications and computing.

Direct laser writing is demonstrated by two‐photon polymerization of multi‐element diffractive optical components that can be switched on and off with an applied voltage. By exploiting the 3D capabilities of the laser microfabrication technique, multiple diffractive optical elements are written into a single liquid crystal (LC) layer. The switching behavior of the diffractive optical elements is controlled by simply changing the write‐voltage of the anisotropic polymer structures during fabrication. Initially, 2D diffraction gratings are written at different depths within the LC layer. Each element is then activated by applying a voltage of sufficient amplitude that causes the second diffractive optical element to become inactive. This is then followed by a demonstration of multi‐element computer generated holograms that are written at different depths within the LC layer. By altering the magnitude of the applied voltage, different images/patterns can be observed in the replay field using a simple electrode configuration. These compact and transmissive LC optical components could excel in applications where a degree of switchability is required but a highly pixelated fully programmable device is excessive.

The decline of Moore’s law coupled with the rise of artificial intelligence has recently motivated research into photonic computing as a high-bandwidth, low-power strategy to accelerate digital electronics. However, many modern-day photonic computing strategies are analogue, making them susceptible to noise and intrinsically difficult to scale. Optical skyrmions offer a route to overcome these limitations through digitization in the form of a discrete topological number that can be assigned to the analogue optical field. Apart from an intrinsic robustness against perturbations, optical skyrmions represent a new medium that has yet to be fully exploited for photonic computing, namely, spatially varying polarization. Here we propose and experimentally demonstrate a method for performing perturbation-resilient integer arithmetic with optical skyrmions and passive optical components, achieving discrete mathematical operations directly using optical skyrmions without external energy input.

Tuneable retarder arrays, such as spatially patterned liquid crystal devices, have given rise to impressive photonic functionality, fuelling diverse applications ranging from microscopy and holography to encryption and communications. Presently these solutions are limited by the controllable degrees of freedom of structured matter, hindering applications that demand photonic systems with high flexibility and reconfigurable topologies. Here we demonstrate a compound modulator that implements a synthetic tuneable arbitrary retarder array as virtual pixels derived by cascading low functionality tuneable devices, realising full dynamic control of its arbitrary elliptical axis geometry, retardance value, and induced phase. Our approach offers unprecedented functionality that is user-defined and possesses high flexibility, allowing our modulator to act as a new beam generator, analyser, and corrector, opening an exciting path to tuneable topologies of light and matter.

Electromagnetic filtering is essential for the coherent control, operation and readout of superconducting quantum circuits at milliKelvin temperatures. The suppression of spurious modes around transition frequencies of a few GHz is well understood and mainly achieved by on-chip and package considerations. Noise photons of higher frequencies – beyond the pair-breaking energies – cause decoherence and require spectral engineering before reaching the packaged quantum chip. The external wires that pass into the refrigerator and go down to the quantum circuit provide a direct path for these photons. This article contains quantitative analysis and experimental data for the noise photon flux through coaxial, filtered wiring. The attenuation of the coaxial cable at room temperature and the noise photon flux estimates for typical wiring configurations are provided. Compact cryogenic microwave low-pass filters with CR-110 and Esorb-230 absorptive dielectric fillings are presented along with experimental data at room and cryogenic temperatures up to 70 GHz. Filter cut-off frequencies between 1 to 10 GHz are set by the filter length, and the roll-off is material dependent. The relative dielectric permittivity and magnetic permeability for the Esorb-230 material in the pair-breaking frequency range of 75 to 110 GHz are measured, and the filter properties in this frequency range are calculated. The estimated dramatic suppression of the noise photon flux due to the filter proves its usefulness for experiments with superconducting quantum systems.

With the growing use of optical polarization in applications ranging from communications to medical diagnoses, adaptive correction of complex vectorial aberrations in optical systems has become an increasingly important area of research. However, research to date has focused primarily on phase and retardance aberrations, whereas another major source of aberration—diattenuation—remains largely unexplored. Unlike the others, diattenuation affects intensity in addition to phase and polarization, limiting the intrinsic correction capability of adaptive systems. In this work, we propose the use of optical skyrmions to probe diattenuation-aberrated systems and provide metrics that characterize the performance of vectorial adaptive optics (V-AO), with theoretical and experimental validations. Based on the probed results, we demonstrate V-AO correction under real-world aberrations for complex media imaging and analyze correction strategies to optimize measurements in aberrated polarimetric systems. This work paves the way for high-dimensional aberration correction, introduces a previously unidentified use of optical skyrmions, and provides insights that will aid the development of vectorial measurement systems.