Circularly polarized light is utilized in various optical techniques and devices. However, using conventional optical systems to generate, analyse and detect circularly polarized light involves multiple optical elements, making it challenging to realize miniature and integrated devices. While a number of ultracompact optical elements for manipulating circularly polarized light have recently been demonstrated, the development of an efficient and highly selective circularly polarized light photodetector remains challenging. Here we report on an ultracompact circularly polarized light detector that combines large engineered chirality, realized using chiral plasmonic metamaterials, with hot electron injection. We demonstrate the detector's ability to distinguish between left and right hand circularly polarized light without the use of additional optical elements. Implementation of this photodetector could lead to enhanced security in fibre and free-space communication, as well as emission, imaging and sensing applications for circularly polarized light using a highly integrated photonic platform.

In the emerging field of thermoplasmonics, Joule heating associated with optically resonant plasmonic structures is exploited to generate nanoscale thermal hotspots.In the present study, new methods for designing and thermally probing thermoplasmonic structures are reported. A general design rationale, based on Babinet's principle, is developed for understanding how the complementary version of ideal electromagnetic antennae can yield efficient nanoscale heat sources with maximized current density. Using this methodology, we show that the diabolo antenna is more suitable for heat generation compared with its more well-known complementary structure, the bow-tie antenna. We also demonstrate that highly localized and enhanced thermal hot spots can be realized by incorporating the diabolo antenna into a plasmonic lens. Using a newly developed thermal microscopy method based on the temperature-dependent photoluminescence lifetime of thin-film thermographic phosphors, we experimentally characterize the thermal response of various antenna and superstructure designs. Data from FDTD simulations and the experimental temperature measurements confirm the validity of the design rationale. The thermal microscopy technique, with its robust sensing method, could overcome some of the drawbacks of current micro/nanoscale temperature measurement schemes.

Circularly polarized light is utilized in various optical techniques and devices. However, using conventional optical systems to generate, analyse and detect circularly polarized light involves multiple optical elements, making it challenging to realize miniature and integrated devices. While a number of ultracompact optical elements for manipulating circularly polarized light have recently been demonstrated, the development of an efficient and highly selective circularly polarized light photodetector remains challenging. Here we report on an ultracompact circularly polarized light detector that combines large engineered chirality, realized using chiral plasmonic metamaterials, with hot electron injection. We demonstrate the detector's ability to distinguish between left and right hand circularly polarized light without the use of additional optical elements. Implementation of this photodetector could lead to enhanced security in fibre and free-space communication, as well as emission, imaging and sensing applications for circularly polarized light using a highly integrated photonic platform.

Precise control of a material's emissivity is critical for thermal-engineering applications. Metamaterials, which derive their optical properties from sub-wavelength structures, have emerged as a promising way to tune emissivity over a wide parameter space. However, metamaterial designs have not yet achieved simultaneous spatial and temporal control of emissivity, which is important for advanced engineering applications such as adaptive thermal management and reconfigurable infrared camouflage. Here, spatiotemporal emissivity control is demonstrated by designing and fabricating a large-area, infrared metamaterial that is modulated with ultraviolet (UV) light. The UV light generates free carriers in a photosensitive ZnO spacer layer, which changes the metamaterial optical properties and causes a localized increase in emissivity. Thermal imaging of the metamaterial during UV illumination reveals an apparent temperature increase as a result of the emissivity change. The imaged temperature fluctuation is recorded under exposure from a temporally modulated and spatially patterned UV illumination source to characterize both the temporal response and spatial resolution of the emissivity change. The results of this work demonstrate new capabilities for thermal metamaterials that could bring about the next generation of thermal-engineering devices.

We report comparative experimental and theoretical studies of second and third harmonic generation from a 20nm-thick indium tin oxide layer in proximity of the epsilonnear-zero condition. Using a tunable OPA laser we record both spectral and angular dependence of the generated harmonic signals close to this particular point. In addition to the enhancement of the second harmonic efficiency close to the epsilon-near-zero wavelength, at oblique incidence third harmonic generation displays unusual behavior, predicted but not observed before. We implement a comprehensive, first-principles hydrodynamic approach able to simulate our experimental conditions. The model is unique, flexible, and able to capture all major physical mechanisms that drive the electrodynamic behavior of conductive oxide layers: nonlocal effects, which blueshift the epsilon-near-zero resonance by tens of nanometers; plasma frequency redshift due to variations of the effective mass of hot carriers; charge density distribution inside the layer, which determines nonlinear surface and magnetic interactions; and the nonlinearity of the background medium triggered by bound electrons. We show that by taking these contributions into account our theoretical predictions are in very good qualitative and quantitative agreement with our experimental results. We show that by taking these contributions into account our theoretical predictions are in very good qualitative and quantitative agreement with our experimental results. We expect that our results can be extended to other geometries where ENZ nonlinearity plays an important role.; in ε and out ε are the dielectric constants inside and outside the medium, respectively; z in E and z out E are the corresponding longitudinal components of the electric field amplitude, and require oblique incidence to excite the ENZ point. Therefore, if in ε decreases, then z in E increases and nonlinear optical phenomena are enhanced, including nonlinear index of refraction [1], harmonic generation, optical bistability, and soliton excitation [2-13].While ENZ materials can be made artificially, all natural bulk materials that display a Lorentz-like response also exhibit a real part of the dielectric permittivity that crosses zero, in