Optical Spin Waves.

Chirality is inherent to a broad range of systems, including solid-state and wave physics. The precession (chiral motion) of the magnetic moments in magnetic materials, forming spin waves, has various properties and many applications in magnetism and spintronics. We show that an optical analogue of spin waves can be generated in arrays of plasmonic nanohelices.

Optomagnetism with a plasmonic skyrmion.

Research at the frontier between optics and magnetism is revealing a wealth of innovative phenomena and avenues of exploration. Optical waves are demonstrating the capacity to induce ultrafast magnetism, while optical analogs of magnetic states, such as magnetic skyrmions, offer the prospect of novel, to the best of our knowledge, spin-optical states. In this Letter, we strengthen the synergy between light and magnetism by exploring the ability of plasmonic Neel skyrmions to create an optomagnetic field, i.

Six-probe scintillator dosimeter for treatment verification in HDR-brachytherapy.

Background: In vivo dosimetry (IVD) is gaining interest for treatment delivery verification in HDR-brachytherapy. Time resolved methods, including source tracking, have the ability both to detect treatment errors in real time and to minimize experimental uncertainties. Multiprobe IVD architectures holds promise for simultaneous dose determinations at the targeted tumor and surrounding healthy tissues while enhancing measurement accuracy.

Multipixel x ray detection integrated at the end of a narrow multicore fiber.

We introduce and demonstrate the concept of a multipixel detector integrated at the tip of an individual multicore fiber. A pixel consists here of an aluminum-coated polymer microtip incorporating a scintillating powder. Upon irradiation, the luminescence released by the scintillators is efficiently transferred into the fiber cores owing to the specifically elongated metal-coated tips that ensure efficient luminescence matching to the fiber modes.

Bloch Surface Waves in Open Fabry-Perot Microcavities.

Thanks to the increasing availability of technologies for thin film deposition, all-dielectric structures are becoming more and more attractive for integrated photonics. As light-matter interactions are involved, Bloch Surface Waves (BSWs) may represent a viable alternative to plasmonic platforms, allowing easy wavelength and polarization manipulation and reduced absorption losses. However, plasmon-based devices operating at an optical and near-infrared frequency have been demonstrated to reach extraordinary field confinement capabilities, with localized mode volumes of down to a few nanometers.

Characterization of a miniaturized scintillator detector for time-resolved treatment monitoring in HDR-brachytherapy.

HDR brachytherapy combines steep dose gradients in space and time, thereby requiring detectors of high spatial and temporal resolution to perform accurate treatment monitoring. We demonstrate a miniaturized fiber-integrated scintillator detector (MSD) of unmatched compactness which fulfills these conditions.The MSD consists of a 0.

Optomagnets in nonmagnetic plasmonic nanostructures: erratum.

This erratum amends two errors in Opt. Lett.46, 613 (2021)OPLEDP0146-959210.

Miniaturized scintillator dosimeter for small field radiation therapy.

The concept of a miniaturized inorganic scintillator detector is demonstrated in the analysis of the small static photon fields used in external radiation therapy. Such a detector is constituted by a 0.25 mm diameter and 0.

Plasmonic Helical Nanoantenna As a Converter between Longitudinal Fields and Circularly Polarized Waves.

A wide variety of optical applications and techniques require control of light polarization. So far, the manipulation of light polarization relies on components capable of interchanging two polarization states of the transverse field of a propagating wave (e.g.

Vortex Beam Generation by Spin-Orbit Interaction with Bloch Surface Waves.

Axis-symmetric grooves milled in metallic slabs have been demonstrated to promote the transfer of Orbital Angular Momentum (OAM) from far- to near-field and vice versa, thanks to spin-orbit coupling effects involving Surface Plasmons (SP). However, the high absorption losses and the polarization constraints, which are intrinsic in plasmonic structures, limit their effectiveness for applications in the visible spectrum, particularly if emitters located in close proximity to the metallic surface are concerned. Here, an alternative mechanism for vortex beam generation is presented, wherein a free-space radiation possessing OAM is obtained by diffraction of Bloch Surface Waves (BSWs) on a dielectric multilayer.

Optomagnets in nonmagnetic plasmonic nanostructures.

Using a simplified hydrodynamic model of the free electron gas of a metal, we theoretically investigate optically induced DC current loops in a plasmonic nanostructure. Such current loops originate from an optical rectification process relying on three electromotive forces, one of which arises from an optical spin-orbit interaction. The resulting static magnetic field is found to be maximum and dramatically confined at the corners of the plasmonic nanostructure, which reveals the ability of metallic discontinuities to concentrate and tailor static magnetic fields on the nanoscale.

Miniaturized fiber dosimeter of medical ionizing radiations on a narrow optical fiber.

Fiber dosimeters have recently drawn much interest for measuring in vivo and in real time the dose of medical radiations. This paper presents the first miniaturized fiber dosimeter integrated at the end of a narrow 125 μm outer diameter optical fiber. Miniaturization is rendered possible by exploiting the concept of a leaky wave optical antenna for interfacing the scintillators and the fiber and by taking advantage of the low propagation loss of narrow silica fibers and high detection yield of single-pixel photon counters.

Subwavelength polarization optics via individual and coupled helical traveling-wave nanoantennas.

Light polarization control is a key factor in modern photonics. Recent advances in surface plasmon manipulation have introduced the prospect of more compact and more efficient devices for this purpose. However, the current plasmonic-based polarization optics remain much larger than the wavelength of light, which limits the design degrees of freedom.

Chiroptical transmission through a plasmonic helical traveling-wave nanoantenna, towards on-tip chiroptical probes.

Resonant plasmonic helices have been widely utilized for locally enhancing and tailoring optical chirality. Here we investigate their nonresonant operation through the recently introduced concept of a plasmonic helical "traveling-wave" nanoantenna. Relying on the coupling of a nonresonant plasmonic helix and a nano-aperture, the helical traveling-wave nanoantenna transmits circularly polarized light with the same handedness as the helix and blocks the other, with a measured dissymmetry factor larger than 1.

Bloch surface waves at the telecommunication wavelength with lithium niobate as the top layer for integrated optics.

Lithium niobate (LN)-based devices are widely used in integrated and nonlinear optics. This material is robust and resistive to high temperatures, which makes the LN-based devices stable, but challenging to fabricate. In this work, we report on the design, manufacturing, and characterization of engineered dielectric media with thin-film LN (TFLN) on top for the coupling and propagation of electromagnetic surface waves at telecommunication wavelengths.

Magnetic spin-orbit interaction of light.

We study the directional excitation of optical surface waves controlled by the magnetic field of light. We theoretically predict that a spinning magnetic dipole develops a tunable unidirectional coupling of light to transverse electric (TE) polarized Bloch surface waves (BSWs). Experimentally, we show that the helicity of light projected onto a subwavelength groove milled into the top layer of a 1D photonic crystal (PC) controls the power distribution between two TE-polarized BSWs excited on both sides of the groove.

Directing Nanoscale Optical Flows by Coupling Photon Spin to Plasmon Extrinsic Angular Momentum.

As any physical particle or object, light undergoing a circular trajectory features a constant extrinsic angular momentum. Within strong curvatures, this angular momentum can match the spin momentum of a photon, thus providing the opportunity of a strong spin-orbit interaction. Using this effect, we demonstrate tunable symmetry breaking in the coupling of light into a curved nanoscale plasmonic waveguide.

Polarization controlled directional propagation of Bloch surface wave.

Bloch surface waves (BSWs) are recently developing alternative to surface plasmon polaritons (SPPs). Due to dramatically enhanced propagation distance and strong field confinement these surface states can be successfully used in on-chip all-optical integrated devices of increased complexity. In this work we propose a highly miniaturized grating based BSW coupler which is gathering launching and directional switching functionalities in a single element.

Ultracompact x-ray dosimeter based on scintillators coupled to a nano-optical antenna.

We show that nano-optical antennas are capable of controlling the luminescence induced by the absorption of x rays into matter. The x-ray-excited luminescence from a tiny scintillation cluster coupled to a horn nano-optical antenna is highly directed and determined by the antenna's geometrical parameters. Directionality is sufficiently high to efficiently outcouple the x-ray-excited luminescence to a narrow single-mode optical fiber, thus enabling ultracompact fiber-integrated x-ray sensors.

Doubly Resonant Photonic Antenna for Single Infrared Quantum Dot Imaging at Telecommunication Wavelengths.

Colloidal quantum dots (CQDs) have drawn strong interest in the past for their high prospects in scientific, medical, and industrial applications. However, the full characterization of these quantum emitters is currently restricted to the visible wavelengths, and it remains a key challenge to optically probe single CQDs operating in the infrared spectral domain, which is targeted by a growing number of applications. Here, we report the first experimental detection and imaging at room temperature of single infrared CQDs operating at telecommunication wavelengths.

Tunable Bloch surface waves in anisotropic photonic crystals based on lithium niobate thin films.

We present an original type of one-dimensional photonic crystal that includes one anisotropic layer made of a lithium niobate thin film. We demonstrate the versatility of such a device sustaining different Bloch surface waves (BSWs), depending on the orientation of the incident wave. By varying the orientation of the illumination of the multilayer, we measured an angle variation of 7° between the BSWs corresponding to the extraordinary and the ordinary index of the lithium niobate thin film.

Double-way spectral tunability for the control of optical nanocavity resonance.

Scanning Near-field Optical Microscopy (SNOM) has been successful in finely tuning the optical properties of photonic crystal (PC) nanocavities. The SNOM nanoprobes proposed so far allowed for either redshifting or blueshifting the resonance peak of the PC structures. In this paper, we theoretically demonstrate the possibility of a redshifting (up to +0.

Unidirectional sub-diffraction waveguiding based on optical spin-orbit coupling in subwavelength plasmonic waveguides.

Subwavelength plasmonic waveguides show the unique ability of strongly localizing (down to the nanoscale) and guiding light. These structures are intrinsically two-way optical communication channels, providing two opposite light-propagation directions. As a consequence, when light is coupled to these planar integrated devices directly from the top (or bottom) surface using strongly focused beams, it is equally shared into the two opposite propagation directions.

Axicon on a gradient index lens (AXIGRIN): integrated optical bench for Bessel beam generation from a point-like source.

We propose and demonstrate a novel concept of a compact optical component aimed at transforming a point-like source into a Bessel beam. This component, called AXIGRIN, consists of an axicon fabricated at the end facet of a gradient index lens. It can be directly coupled to an optical fiber, a microscope objective, or vertical-external-cavity surface-emitting-laser to be used without preliminary adjustments, which is of practical interest for end users.