arXiv subjects

Yaryna Mamchur

Publications and source records attributed to Yaryna Mamchur.

3 recordsLinked to original sources

arXiv2025

Experimental demonstration of high compression of space by optical spaceplates

The physical size of optical imaging systems is one of the greatest constraints on their use, limiting the performance and deployment of a range of systems from telescopes to mobile phone cameras. Spaceplates are nonlocal optical devices that compress free-space propagation into a shorter distance, paving the way for more compact optical systems, potentially even thin flat cameras. Here, we demonstrate the first engineered optical spaceplate and experimentally observe the highest space compression ratios yet demonstrated in any wavelength region, up to $\mathcal{R}=176\pm14$, which is 29 times higher than any previous device. Our spaceplate is a multilayer stack, a well-established commercial fabrication technology that supports mass production. The versatility of these stacks allows for the freedom to customize the spaceplate's bandwidth and angular range, impossible with previous optical experimental spaceplates, which were made of bulk materials. With the appropriate choice of these two parameters, multilayer spaceplates have near-term applications in light detection and ranging (LIDAR) technologies, retinal scanners, endoscopes, and other size-constrained optical devices.

physics.optics↗

arXiv2021

Ultra-high-Q resonances in plasmonic metasurfaces

Plasmonic nanostructures hold promise for the realization of ultra-thin sub-wavelength devices, reducing power operating thresholds and enabling nonlinear optical functionality in metasurfaces. However, this promise is substantially undercut by absorption introduced by resistive losses, causing the metasurface community to turn away from plasmonics in favour of alternative material platforms (e.g., dielectrics) that provide weaker field enhancement, but more tolerable losses. Here, we report a plasmonic metasurface with a quality-factor (Q-factor) of 2340 in the telecommunication C band by exploiting surface lattice resonances (SLRs), exceeding the record by an order of magnitude. Additionally, we show that SLRs retain many of the same benefits as localized plasmonic resonances, such as field enhancement and strong confinement of light along the metal surface. Our results demonstrate that SLRs provide an exciting and unexplored method to tailor incident light fields, and could pave the way to flexible wavelength-scale devices for any optical resonating application.

physics.optics↗

arXiv2020

Hyperpolarizability of plasmonic meta-atoms in metasurfaces

Plasmonic metasurfaces are promising as enablers of nanoscale nonlinear optics and flat nonlinear optical components. Nonlinear optical responses of such metasurfaces are determined by the nonlinear optical properties of individual nanostructured plasmonic meta-atoms, which are the building blocks of the metasurfaces. Unfortunately, no simple methods exist to determine the nonlinear coefficients (hyperpolarizabilities) of the meta-atoms hindering designing of nonlinear metasurfaces. Here, we develop the equivalent RLC circuit model of such meta-atoms to estimate their second-order nonlinear optical parameter i.e. the first-order hyperpolarizability in the optical spectral range. In parallel, we extract from second-harmonic generation experiments the spectrum of the 1st-order hyperpolarizabilities of individual meta-atoms consisting of asymmetrically shaped (elongated) plasmonic nanoprisms. Moreover, we verify our results using nonlinear hydrodynamic-FDTD and with calculations based on nonlinear scattering theory. All three approaches: analytical, experimental, and computational, yield results that agree very well. Our empirical RLC model can thus be used as a simple tool to enable efficient design of nonlinear plasmonic metasurfaces.

physics.optics↗