Trevon Badloe

Tunable optical devices powered by metasurfaces provide a new path for functional planar optics. In particular, lenses with tunable focal lengths can play a key role in various fields with applications in imaging, displays, and augmented and virtual reality devices. Here, the authors demonstrate an electrically controllable bifocal metalens at visible wavelengths by incorporating a metasurface designed to focus light at two different focal lengths, with liquid crystals to actively manipulate the

Taking inspiration from beautiful colors in nature, structural colors produced from nanostructured metasurfaces have shown great promise as a platform for bright, highly saturated, and high-resolution colors. Both plasmonic and dielectric materials have been employed to produce static colors that fulfil the required criteria for high-performance color printing, however, for practical applications in dynamic situations, a form of tunability is desirable. Combinations of the additive color palette

The imaging of microscopic biological samples faces numerous difficulties due to their small feature sizes and low-amplitude contrast. Metalenses have shown great promise in bioimaging as they have access to the complete complex information, which, alongside their extremely small and compact footprint and potential to integrate multiple functionalities into a single device, allow for miniaturized microscopy with exceptional features. Here, we design and experimentally realize a dual-mode metalen

In the field of nanophotonics, metasurfaces have come to the forefront in real‐world applications, owing to their accessible exotic optical properties that can be readily designed and fabricated using currently available techniques. The subwavelength dimensions and lightweight characteristics of metasurfaces are attractive qualities for the miniaturization of optical devices and are already exploited in devices that can rival, and sometimes even outperform, conventional bulky optics. Over the pa

The explosion in the amount of information that is being processed is prompting the need for new computing systems beyond existing electronic computers. Photonic computing is emerging as an attractive alternative due to performing calculations at the speed of light, the change for massive parallelism, and also extremely low energy consumption. We review the physical implementation of basic optical calculations, such as differentiation and integration, using metamaterials, and introduce the reali

In the past decade, the realisation of negative index materials has initiated extensive research into metamaterials. Perfect absorbers and reflectors are of particular interest as their usefulness is endless in a range of different fields and devices. Since it was originally shown that a device can achieve unity absorption of electromagnetic waves, it has become a hot area of research to develop perfect absorbers based on polarisation independence and incident angle independence, at a range of f

By learning the optimal policy with a double deep Q-learning network (DDQN), we design ultra-broadband, biomimetic, perfect absorbers with various materials, based the structure of a moth's eye. All absorbers achieve over 90% average absorption from 400 to 1600 nm. By training a DDQN with moth-eye structures made up of chromium, we transfer the learned knowledge to other, similar materials to quickly and efficiently find the optimal parameters from the ∼1 billion possible options. The knowledge

Two biomimetic, moth-eye structure, perfect absorbers in the visible and near infrared regions are introduced and investigated. The moth-eye structure is made up of vanadium oxide (VO₂), which is a phase change material that changes from an insulator state to a metallic state at around 85 °C. The VO₂ structure sits on top of a sapphire (Al₂O₃) dielectric spacer layer, above a gold (Au) back reflector. Two perfect absorbers are designed, one with perfec

Abstract As the quest for active photonic devices continues, materials with exotic and exploitable properties have become paramount to enable new advancements. In recent years, phase‐change materials (PCMs) have emerged as an exciting option that open new gateways for both fundamental physics and material science research, while also being applicable to actively tunable photonic devices. One PCM in particular, vanadium dioxide (VO 2 ), has gained a lot of attention due to its interesting reversi