Alchemically-glazed plasmonic nanocavities using atomic layer metals: controllably synergizing catalysis and plasmonics

Shu Hu ,EricS.A.Goerlitzer ,QianqiLin Vyacheslav M. Silkin,& Jeremy J. Baumberg, Bart de Nijs

https://doi.org/10.1038/s41467-025-58578-9

Plasmonic nanocavities offer exceptional confinement of light, making them effective for energy conversion applications. However, limitations with stability, materials, and chemical activity have impeded their practical implementation. Here we integrate ultrathin palladium (Pd) metal films from sub- to few- atomic monolayers inside plasmonic nanocavities using underpotential deposition. Despite the poor plasmonic properties of bulk Pd in the visible region, minimal loss in optical field enhancement is delivered along with Pd chemical enhancement, as confirmed by ab initio calculations. Such synergistic effects significantly enhance photocatalytic activity of the plasmonic nanocavitiesaswelasphotostabilityby suppressing surface atom migration. We show the atomic alchemical-glazing approach is general for a range of catalytic metals that bridge plasmonic and chemical catalysis, yielding broad applications in photocatalysis for optimal chemical transformation.

Fig. Alchemical space for atomic-glazing on Au substrates.

congratulation to Our new paper 🎉

M.Asadolah Salmanpour, M. Mosleh & S. M. Hamidi^*
Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran.

This study presents a dual-frequency modulation scheme in which both optical and microwave fields are simultaneously modulated in a microwave–optical double resonance system within a hot rubidium vapor cell. The combined modulation produces harmonic spectral features at the sum and difference of the individual modulation frequencies, indicating nonlinear coupling between the fields. Experimental results reveal that this approach enables modulation of atomic population dynamics and facilitates efficient population transfer between hyperfine levels. The observed frequency mixing highlights the system’s sensitivity to dual modulation and suggests its potential for enhancing the spectral control of atomic transitions. These findings may support future developments in atomic clocks, high-precision magnetometers, and quantum information processing systems.

Two-photon polymerization for biological applications

Alexander K. Nguyen and Roger J. Narayan

Materials Today Volume 20,Number 6 July/August 2017

UNC/NCSU Joint Department of Biomedical Engineering, North Carolina State University, Raleigh, NC 27695-7115, USA

https://doi.org/10.1016/j.mattod.2017.06.004

Two-photon polymerization (2PP) leverages the two-photon absorption (TPA) of near-infrared (NIR) radiation for additive manufacturing with sub-diffraction limit resolution within the bulk of a photosensitive material. This technology draws heavily on photosensitive polymers from the microelectronics industry, which were not optimized for TPA or for biocompatibility. 2PP with sub 100 nm resolution has been repeatedly demonstrated; however, this level of fabrication resolution comes at the expense of long fabrication times. Manufacturing of medical devices beyond surface texturing would be prohibitively slow using the current state of the art 2PP technology. Current research intoTPA-sensitivephotopolymerswithgoodbiocompatibilityandholographicprojectionsusingspatial light modulators address current technological limitations by providing materials specifically formulated for biological applications and by making better use of available laser power for applications in which nanoscale resolution is not required.

Optical setup of a femtosecond laser imaging and microfabrication system, which is capable of fluorescence lifetime imaging microscopy. Reprinted from Ref.

congratulation to Our new paper in Journal of Applied Physics A

Laser induced fluorescence enhancement by surface lattice resonance in two dimensional plasmonic nanostructure

Noor D. Abdulameer, N. S. Shnan, Lazem Hassan Aboud, S. M. hamidi

We have experimentally examined the effect of surface lattice resonance in two dimensional plasmonic structure onto the laser induced fluorescence. For this purpose, we fabricated main sample by soft nanolithography onto the polydimethylsiloxane and cover it by gold thin layer by the aid of sputtering machine. The host medium of the dye achieved by spin coating of the Rh6G over the two dimensional plasmonic sample. We recorded the spectral response of the multilayer sample as the fluorescence signal by spectrometer in all of the visible region under four different pump intensities. Our results indicate that the localized electric field due to surface lattice resonance as well as exciton of the dye medium can couple together to reach the plexciton and thus plasmon enhance laser induced fluorescence takes place which can be useful as new substrate in this area for visible region.

Effect of Neighboring Transitions on Critical Angle in Conversion between EIA and EIT in 87Rb Atoms

Preprints.org

Aisar-ul Hassan , Heung-Ryoul Noh ,and Jin-Tae Kim

Posted Date: 22 October 2024

doi:10.20944/preprints202410.1613.v1

The effects of neighboring transitions (ENT) on electromagnetically induced transparency (EIT), electromagnetically induced absorption (EIA), and the conversion between EIA and EIT in a degenerate multi-level system of 87Rb atoms were studied in mmmterms of the angle (θ) between the polarization axes of the coupling and probe beams. The predicted critical values of θ, in which EIT transitioned to EIA, were consistent with the experimental values. In this work these results were systematically conrmed using the calculated spectra by varying the frequency spacings in the excited state of 87Rb via a factor called the ratio. We observed that when the ratio was less than 0.1, the critical angle θc was inverted. This may be attributed to the interplay between the strengths of the EIA and EIT as the ENT varied. We also discovered that by modifying the frequency spacings in the excited state of 87Rb, it becomes feasible to predict ENT and the interplay between EIT and EIA in alkali-metal atoms.

Schematic of the experimental setup. SAS: saturated absorption spectroscopy; W: window; HWP: half-wave plate; PBS: polarizing beam splitter; BE: beam expander; AOM: acousto-optic modulator; M: mirror; BS: beam splitter; Bd: beam dump; PD: photodetector.

congratulation to Dear Dr Zahraa for her PhD defense

The research focus on the design and investagation of reconfigrable metasurface based graphene optical antennas for beam steering and beam focusing applications

congratulation for our new paper:Plasmonic smart contact lens based on etalon nanostructure for tear glucose sensing

Journal of scientific reports

N. Roostaei & S. M. Hamidi

Smart contact lenses, one of the most advanced wearable platforms, offer a combination of optical and electronic technologies that provide exceptional capabilities in various fields. These lenses are equipped with biosensors, microchips, and sometimes even miniature displays that enable the collection and analysis of biological and environmental data. Smart contact lenses represent a big leap in wearable technology and biosensors, potentially providing a new future for human interaction with the digital world, improving personal health, and promising a hopeful future in vision and wearable technologies. In this study, smart contact lenses based on plasmonic etalon nanostructure have been proposed and fabricated for tear glucose sensing. A cost-effective and simple technique of soft nanolithography has been proposed to fabricate a plasmonic sensor chip on a contact lens, enabling the detection of glucose solutions at different concentrations of 0.15, 1.5, 5, and 10 mM in a phosphate-buffered saline (PBS) solution. The proposed plasmonic etalon-based smart contact lens as a wearable platform exhibits the capacity to sense tear glucose (even at low concentration values) and offers relatively high sensitivity for non-invasive tear glucose sensing applications. The biocompatibility, cost-effectiveness, stability, and simple production of these contact lenses may provide new perspectives on wearable biosensors.

Plasmonic Ring Resonator‑Based Sensors: Design, Performance, and Applications

Plasmonics
https://doi.org/10.1007/s11468-025-02890-z

REVIEW ، The Author(s) 2025

C. S. Mallika · M. Shwetha

Plasmonic ring resonators have emerged as a powerful platform for high sensitivity, small footprint, and versatility across various applications when compared to traditional optical sensors. In this review, the key design principles, performance characteristics through geometrical tuning, material selection, and challenges across multiple sensing applications of plasmonic ring resonator are discussed. Research to improve their design capabilities to get real-time results with minimal sample preparation underscores the signicant im pact of plasmonic ring resonator on future sensing technologies. By exploiting the resonant behavior and the strong eld connement of sur face plasmon polaritons, they can achieve high sensitivity and compact footprints, attracting them for various sensing applications, particularly for biological and chemical sensing applications. Moreover, with ongoing advancements in fabrication techniques, nanophotonics, and material science, the potential applications of sensing technology have surpassed beyond expectations. However, the challenges like fabrication complexity, eectiv e coupling methods, material losses environmental impact on sensor performance, and precision alignment while integrating plasmonic components with ring resonators are addressed and the possible solutions are discussed for the future investigation.

a: Working principle of SPR and b: LSPR

congratulation for our new paper:Magneto-optical Kerr effect in Metasurface Flexible Microarrays by near field excitation

Journal of theoretical and applied physics

N. S. Shnan, N. Roostaei, S. M. Hamidi, V. I. Belotelov, A. I. Chernov

We have experimentally examined the effect of light localization and near field effect on the magneto-optical response of the two-dimensional coupled micro-ring periodic structure. For this purpose, we fabricated main template by laser writing system and stamped it by polydimethylsiloxane-to reach the main two-dimensional microstructures. Thus, we coated them with a gold layer and Ni layer as plasmonic and magnetic metasurfaces, respectively. We recorded the spectral magneto-optical longitudinal Kerr effect under 200 mT and the spectrometer’s response in all visible regions under the normal condition as well as pump and probe system by the aid of green laser as pump. The pump was done via high numerical aperture objective lens to excite near field of plasmon in a two-dimensional structure. Our results indicate that the localized surface plasmon resonance, surface lattice resonance as well as electric and magnetic dipole moments enhance the magneto-optical response in two closer channels in the middle of visible region.

A photonic crystal receiver for Rydberg atom-based sensing

Hadi Amarloo, Mohammad Noaman, Su-Peng Yu, Donald Booth, Somayeh Mirzaee, Rajesh Pandiyan, Florian Christaller, James P. Shaffer

Rydberg atom-based sensors use atoms dressed by lasers to detect and measure radio frequency electromagnetic fields. The absorptive properties of the atomic gas, configured as a Rydberg atom-based sensor, change in the presence of a radio frequency electromagnetic field. While these sensors are reasonably sensitive, the best conventional radio frequency sensors still outperform Rydberg atom-based sensors with respect to sensitivity. One approach to increase the sensitivity of Rydberg atom-based sensors is to engineer the vapor cell that contains the atomic gas. In this work, we introduce a passive, all-dielectric amplifier integrated into a Rydberg atom-based sensor vapor cell. The vapor cell is a combination of a slot waveguide and a photonic crystal. The structural features of the vapor cell yield a power amplification of ~24 dB. The radio frequency electromagnetic field is coupled adiabatically into the slot waveguide and slowed to increase the interaction between the radio frequency field and the atoms to effectively amplify the incoming signal, i.e., increase the Rabi frequency on the radio frequency transition. The work shows the utility of vapor cell engineering for atom-based quantum technologies and paves the way for other such devices.

Fig. Photonic crystal vapor cell with slot region
filled with Cs atoms, and taper structure for mode
conversion of the incoming free space RF
electromagnetic wave. The holes are organized to
produce a photonic crystal that slows an RF elec-
tromagnetic wave propagating along the x axis
around a specific frequency. The slot is hermetically
sealed with glass on both sides and filled with Cs
atoms. The device uses a thermally activated getter
source to load the Cs atoms, shown as the disc in the
circular pocket separated from, but fluidly coupled
to the slot. Light is coupled in along the z axis after
being combined using beam splitters (BS) and
expanded using cylindrical lenses. The light is
detected using a photodiode (PD). A piece of glass
Parallel to the vapor cell is used to tune the frequency
of the resonance.