Here, we propose liquid-crystal (LC) integrated metasurfaces to create intensity-tunable metaholography in the visible spectrum. The metasurface is composed of gap-shifted split ring resonators, which exhibit different optical responses depending on the input polarization states of light. The gap-shifted split ring resonators enable the perfect absorption of right-circularly polarized light (RCP), while they reflect left-circularly polarized with varied retardation phases. the integration of LC enables electrically tunable metaholograms, where the intensity of the holographic images can be adjusted by controlling the applied voltages on LC. The circular dichroism in reflection reaches (experiments) 0.91 and (simulations) 0.99.
Plasmonic resonance energy transfer (PRET) based imaging has been proposed as an effective label-free real-time biomolecular absorption spectroscopic method that enables the detection of biomolecules and dynamic cell activities. Here, we present a metasurface-based PRET-imaging platform that effectively engineers the darkfield scattering spectrum using the gap plasmon and grating effect. As a demonstration, three different biomolecules (Cyt c, Chl a, Chl b) are simultaneously detected using our metasurface-based PRET-imaging platform. Our proposed metasurface-based PRET-imaging platform enables continuous monitoring in the spatial region and multiplexed PRET sensing of multiple biomolecules with different absorption spectrums in the visible.
Optical resolution photoacoustic microscopy (OR-PAM) provides high optical contrast and lateral resolution. However, the resolution of a typical OR-PAM using an objective lens is limited to not exceeding Abbe's optical diffraction limit. In this study, a lensless shear force scanning PAM is presented. Instead of a lens, the system uses an imaging probe that combines a non-coated tapered fiber with a quartz tuning fork (QTF). A shear force feedback mechanism is used to maintain a tens of nm (near-field) distance between the fiber tip and the sample. With the system, PA signals generated in the near field of a gold sputtered glass sample were successfully acquired. We also performed 2D PA scanning experiments and obtained PA images of gold cube samples with high lateral resolution. This study demonstrates the existence of a near field PA signal and shows its potential for super-resolution scanning PAM.
Tunable metasurfaces have been steadily investigated to miniaturize optical devices by altering active module that is equipped with mechanical actuators. However, almost all of recent tunable metasurfaces focused on switching functionality between two distinct states or more. Here, we proposed spin-selective metasurfaces, which perfectly absorb certain circularly polarized light, while reflecting counter circularly polarized light with desired phases. The metasurfaces consist of split ring resonators on metal-dielectric metal structures to enlarge their plasmonic responses, approaching near-zero reflection of LCP, and 14% reflection of RCP at the wavelength of 635 nm. With the metasurface, we implanted it on electrically tunable liquid crystals for intensity tuning of encoded holograms. 23-steps of hologram intensities are experimentally demonstrated with liquid crystal integrated split ring resonators. Considering that previous spin-selective metasurfaces are designed with a complex fabrication process, our liquid crystal integrated split ring resonators will be a dominant option for altering active and bulky optical components.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.