| 1. |
- Alarcon, Alvaro, et al.
(författare)
-
All-in-Fiber Dynamically Reconfigurable Orbital Angular Momentum Mode Sorting
- 2023
-
Ingår i: ACS Photonics. - : AMER CHEMICAL SOC. - 2330-4022. ; 10:10, s. 3700-3707
-
Tidskriftsartikel (refereegranskat)abstract
- The orbital angular momentum (OAM) spatial degree of freedom of light has been widely explored in many applications, including telecommunications, quantum information, and light-based micromanipulation. The ability to separate and distinguish between the different transverse spatial modes is called mode sorting or mode demultiplexing, and it is essential to recover the encoded information in such applications. An ideal d mode sorter should be able to faithfully distinguish between the different d spatial modes, with minimal losses, and have d outputs and fast response times. All previous mode sorters rely on bulk optical elements, such as spatial light modulators, which cannot be quickly tuned and have additional losses if they are to be integrated with optical fiber systems. Here, we propose and experimentally demonstrate, to the best of our knowledge, the first all-in-fiber method for OAM mode sorting with ultrafast dynamic reconfigurability. Our scheme first decomposes the OAM mode in-fiber-optical linearly polarized (LP) modes and then interferometrically recombines them to determine the topological charge, thus correctly sorting the OAM mode. In addition, our setup can also be used to perform ultrafast routing of the OAM modes. These results show a novel and fiber-integrated form of optical spatial mode sorting that can be readily used for many new applications in classical and quantum information processing.
|
|
| 2. |
- Alekseeva, Svetlana, 1987, et al.
(författare)
-
Single Particle Plasmonics for Materials Science and Single Particle Catalysis
- 2019
-
Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 6:6, s. 1319-1330
-
Forskningsöversikt (refereegranskat)abstract
- Single particle nanoplasmonic sensing and spectroscopy is a powerful and at the same time relatively easy-to-implement research method that allows monitoring of changes in the structure and properties of metal nanoparticles in real time and with only few restrictions in terms of surrounding medium, temperature and pressure. Consequently, it has been successfully used in materials science applications to, for instance, reveal the impact of size and shape of single metal nanoparticles on the thermodynamics of metal hydride formation and decomposition. In this Perspective, we review and discuss the research efforts that have spurred key advances in the development of single particle nanoplasmonic sensing and spectroscopy as a research tool in materials science. On this background we then assess the prospects and challenges toward its application in single particle catalysis, with the aim to enable operando studies of the relationship between metal nanoparticle structure or oxidation state and catalytic performance.
|
|
| 3. |
- Andrén, Daniel, 1991, et al.
(författare)
-
Large-Scale Metasurfaces Made by an Exposed Resist
- 2020
-
Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 7:4, s. 885-892
-
Tidskriftsartikel (refereegranskat)abstract
- Phase-gradient metasurfaces have the potential to revolutionize photonics by offering ultrathin alternatives to a wide range of common optical elements, including bulky refractive optics, waveplates, and axicons. However, the fabrication of state-of-the-art metasurfaces typically involves several expensive, time-consuming, and potentially hazardous processing steps. To address this limitation, a facile methodology to construct phase-gradient metasurfaces from an exposed standard electron beam resist is developed. The method dramatically cuts the required processing time and cost as well as reduces safety hazards. The advantages of the method are demonstrated by constructing high-performance flat optics based on the Pancharatnam-Berry phase gradient concept for the entire visible wavelength range. Manufactured devices include macroscopic (1 cm diameter) positive lenses, gratings exhibiting anomalous reflection, and cylindrical metalenses on flexible plastic substrates.
|
|
| 4. |
- Antosiewicz, Tomasz, 1981, et al.
(författare)
-
Localized Surface Plasmon Decay Pathways in Disordered Two-Dimensional Nanoparticle Arrays
- 2015
-
Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 2:12, s. 1732-1738
-
Tidskriftsartikel (refereegranskat)abstract
- The size and shape of a metal nanoparticle determine its optical properties. When placed in an array the single particle response is further modified by the scattered fields, which for a random array are unique to each scatterer. However, at the array level scattering and absorption retain single-particle-like spectra. Using T-Matrix calculations and an analytical model of intra-array coupling in amorphous arrays we show how the branching ratio of the localized plasmon decay depends on disorder and particle density. We calculate the effective polarizability and demonstrate its effects on scattering and absorption. The scattering-to-absorption ratio is a function of particle separation in the disordered array and can significantly deviate from the inherent single particle ratio. We trace the period of this oscillatory dependence of the ratio to the single particle plasmon resonance wavelength. This effect has implications for applications in which one of the decay channels has to be dominant, for example, absorption for hot electron hole pair generation in the metal particles or scattering into a nearby semiconductor.
|
|
| 5. |
- Antosiewicz, Tomasz, 1981, et al.
(författare)
-
Plasmon-Exciton Interactions in a Core-Shell Geometry: From Enhanced Absorption to Strong Coupling
- 2014
-
Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 1:5, s. 454-463
-
Tidskriftsartikel (refereegranskat)abstract
- We present a detailed Mie theory, finite-difference time-domain, and quasi-static study of plasmon-exciton interactions in a spherical core shell geometry. In particular, we report absorption, scattering, and extinction cross sections of a hybrid core-shell system and identify several important interaction regimes that are determined by the electromagnetic field enhancement and the oscillator strength of electronic excitations. We assign these regimes to enhanced-absorption, exciton-induced transparency and strong coupling, depending on the nature of the observed spectra of the coupled plasmon-exciton resonances. We also show the relevance of performing single-particle absorption or extinction measurements in addition to scattering to validate the interaction regime. Furthermore, at relatively high, yet realistic oscillator strengths we observe emergence of a third mode, which is not predicted by a classical coupled harmonic oscillator model and is attributed to the geometrical resonance of the structure as a whole.
|
|
| 6. |
- Anttu, Nicklas
(författare)
-
Shockley-Queisser Detailed Balance Efficiency Limit for Nanowire Solar Cells
- 2015
-
Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 2:3, s. 446-453
-
Tidskriftsartikel (refereegranskat)abstract
- III-V semiconductor nanowire arrays show promise as a platform for next-generation solar cells. However, the theoretical efficiency limit for converting the energy of sunlight into electrical energy in such solar cells is unknown. Here, we calculate through electromagnetic modeling the Shockley-Queisser efficiency limit for an InP nanowire array solar cell. In this analysis, we calculate first from the absorption of sunlight the short-circuit current. Next, we calculate the voltage-dependent emission characteristics of the nanowire array. From these processes, we identify how much current we can extract at a given voltage. Finally, after constructing this current-voltage (IV) curve of the nanowire solar cell, we identify from the maximum power output the maximum efficiency. We compare this efficiency of the nanowire array with the 31.0% efficiency limit of the conventional InP bulk solar cell with an inactive substrate underneath. We consider a nanowire array of 400 nm in period, which shows a high short-circuit current. We optimize both the nanowire length and diameter in our analysis. For example, nanowires of 4 mu m in length and 170 nm in diameter produce 96% of the short-circuit current obtainable in the perfectly absorbing InP bulk cell. However, the nanowire solar cell emits fewer photons than the bulk cell at thermal equilibrium, especially into the substrate. This weaker emission allows for a higher open circuit-voltage for the nanowire cell. As an end result, nanowires longer than 4 mu m can actually show, despite producing a lower short-circuit current, a higher efficiency limit, of up to 32.5%, than the bulk cell.
|
|
| 7. |
- Bahsoun, H., et al.
(författare)
-
Electronic Light-Matter Strong Coupling in Nanofluidic Fabry-Pérot Cavities
- 2018
-
Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 5:1, s. 225-232
-
Tidskriftsartikel (refereegranskat)abstract
- Electronic light-matter strong coupling has been limited to solid molecular films due to the challenge of preparing optical cavities with nanoscale dimensions. Here we report a technique to fabricate such Fabry-Pérot nanocavities in which solutions can be introduced such that light-molecule interactions can be studied at will in the liquid phase. We illustrate the versatility of these cavities by studying the emission properties of Chlorin e6 solutions in both the weak and strong coupling regimes as a function of cavity detuning. Liquid nanocavities will broaden the investigation of strong coupling to many solution-based molecular processes. © 2017 American Chemical Society.
|
|
| 8. |
- Balla, N. K., et al.
(författare)
-
Polarized Nonlinear Nanoscopy of Metal Nanostructures
- 2017
-
Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 4:2, s. 292-301
-
Tidskriftsartikel (refereegranskat)abstract
- Nonlinear signals from metal nanostructures are known to be highly polarization-dependent, due to the intrinsic vectorial nature of nonlinear optical coupling. Nonlinear optical polarization responses contain important information on the near-field properties of nanostructures;, however, they remain complex to monitor and to model at the nanoscale. Polarization resolved nonlinear optical microscopy can potentially address this question; however, the recorded signals are generally averaged over the diffraction-limited size of a few hundreds of nanometers, thus, missing the spatial specificity of the nanostructure's optical response. Here we present a form of polarization resolved microscopy, named polarization nonlinear nanoscopy, which reveals subdiffraction scale vectorial variations of electromagnetic fields, even though the intensity image is diffraction-limited. We show that by exploiting, at a single subdiffraction pixel level, the information gained by the polarization-induced modulation, it is possible to spatially map the vectorial nature of plasmonic nonlinear optical interactions in nanostructures, revealing in particular surface contributions, retardation effects, and anisotropic spatial confinements.
|
|
| 9. |
- Baranov, Denis, 1990, et al.
(författare)
-
Anapole-Enhanced Intrinsic Raman Scattering from Silicon Nanodisks
- 2018
-
Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 5:7, s. 2730-2736
-
Tidskriftsartikel (refereegranskat)abstract
- Enhancement of inelastic light emission processes through resonant excitation usually correlates with enhanced scattering of the excitation light, as is for example typically the case for surface-enhanced fluorescence and Raman scattering from plasmonic nanostructures. Here, we demonstrate an unusual case where a reverse correlation is instead observed, that is, we measure a multifold enhancement of Raman emission along with suppressed elastic scattering. The system enabling this peculiar effect is composed of silicon nanodisks excited in the so-called anapole state, for which electric and toroidal dipoles interfere destructively in the far-field, thereby preventing elastic scattering, while the optical fields in the core of the silicon particles are enhanced, thus, amplifying light-matter interaction and Raman scattering at the Stokes-shifted emission wavelength. Our results demonstrate an unusual relation between resonances in elastic and inelastic scattering from nanostructures and suggest a route toward background-free frequency conversion devices.
|
|
| 10. |
- Baranov, Denis G., et al.
(författare)
-
Toward Molecular Chiral Polaritons
- 2023
-
Ingår i: ACS Photonics. - 2330-4022. ; 10:8, s. 2440-2455
-
Tidskriftsartikel (refereegranskat)abstract
- Coupling between light and material excitations underliesa widerange of optical phenomena. Polaritons are eigenstates of a coupledsystem with a hybridized wave function. Owing to their hybrid composition,polaritons exhibit at the same time properties typical for photonicand electronic excitations, thus offering new ways for controllingelectronic transport and even chemical kinetics. While most theoreticaland experimental efforts have been focused on polaritons with electric-dipolecoupling between light and matter, in chiral quantum emitters, electronictransitions are characterized by simultaneously nonzero electric andmagnetic dipole moments. Thus, it is natural to wonder what kindsof novel effects chirality may enable in the realm of strong light-mattercoupling. Right now, this field located at the intersection of nanophotonics,quantum optics, and chemistry is in its infancy. In this Perspective,we offer our view toward chiral polaritons. We review basic physicalconcepts underlying chirality of matter and electromagnetic field,discuss the main theoretical and experimental challenges that needto be solved, and consider novel effects that could be enabled bystrong coupling between chiral light and matter.
|
|
