Integrated coplanar waveguide coil on diamond for enhanced homogeneous broadband NV magnetometry.

Nitrogen-vacancy (NV) centers in diamond have emerged as promising quantum sensors due to their highly coherent and optically addressable spin states with potential applications in high-sensitivity magnetometry. Homogeneously addressing large ensembles of NV centers offers clear benefit in terms of sensing precision as well as in fundamental studies of collective effects. Such experiments require a spatially uniform, intense, and broadband microwave field that can be difficult to generate. Previous approaches, such as copper wires, loop coils, and planar structures, have shown limitations in field homogeneity, bandwidth, and integration in compact devices. In this paper, we present a coplanar waveguide (CPW) gold coil patterned on a 3 × 3 mm 2 diamond substrate, offering full integration, enhanced stability, and broad bandwidth suitable for various NV sensing applications. Coil fabricated on diamond offers several advantages for magnetometry with NV centers ensemble, including enhanced heat dissipation, seamless integration, scalability, and miniaturization potential. We optimize critical geometrical parameters to achieve a homogeneous magnetic field with a coefficient of variation of less than 6% over an area of 0.5 mm 2 and present experimental results confirming the performance of the proposed CPW coil.

In recent years, there has been significant interest in using nitrogen-vacancy (NV) centers in diamond as quantum sensors for high-sensitivity magnetometry. These NV centers, particularly the negatively charged ones, offer promising applications due to their coherent spin states that can be manipulated using microwave fields and optically detected magnetic resonance techniques. However, to improve measurement precision and signal-to-noise ratio, it's advantageous to address large ensembles of NV centers, which requires a spatially uniform, intense, and broadband microwave field. Various methods, such as copper wires, loop coils, and planar structures, have been explored to achieve this, but with limited capability. To address their limitations, a coplanar waveguide (CPW) gold coil patterned on a CVD diamond substrate is proposed. This design offers a highly homogeneous magnetic field, full integration with the diamond substrate, scalability, miniaturization, and efficient heat dissipation, making it a promising solution for NV magnetometry applications. Experimental results confirm its performance, making it a remarkable advancement in this area.

Low-loss and high-index contrast ultraviolet-C free-standing waveguides made of thermal silicon oxide.

Photonics in the ultraviolet provides an avenue for key advances in biosensing, pharmaceutical research, and environmental sensing. However, despite recent progress in photonic integration, a technological solution to fabricate photonic integrated circuits (PICs) operating in the UV-C wavelength range, namely, between 200 and 280 nm, remains elusive. Filling this gap will open opportunities for new applications, particularly in healthcare. A major challenge has been to identify materials with low optical absorption loss in this wavelength range that are at the same time compatible with waveguide design and large-scale fabrication. In this work, we unveil that thermal silicon oxide (TOX) on a silicon substrate is a potential candidate for integrated photonics in the UV-C, by removing the silicon substrate under selected regions to form single-side suspended ridge waveguides. We provide design guidelines for low-loss waveguide geometries, avoiding wrinkling due to residual intrinsic stress, and experimentally demonstrate waveguides that exhibit optical propagation losses below 3 and 4 dB/cm at a wavelength of 266 nm with claddings of air and water, respectively. This result paves the way for on-chip UV-C biological sensing and imaging.

Light Emission and Conductance Fluctuations in Electrically Driven and Plasmonically Enhanced Molecular Junctions.

Electrically connected and plasmonically enhanced molecular junctions combine the optical functionalities of high field confinement and enhancement (cavity function), and of high radiative efficiency (antenna function) with the electrical functionalities of molecular transport. Such combined optical and electrical probes have proven useful for the fundamental understanding of metal-molecule contacts and contribute to the development of nanoscale optoelectronic devices including ultrafast electronics and nanosensors. Here, we employ a self-assembled metal-molecule-metal junction with a nanoparticle bridge to investigate correlated fluctuations in conductance and tunneling-induced light emission at room temperature. Despite the presence of hundreds of molecules in the junction, the electrical conductance and light emission are both highly sensitive to atomic-scale fluctuations-a phenomenology reminiscent of picocavities observed in Raman scattering and of luminescence blinking from photoexcited plasmonic junctions. Discrete steps in conductance associated with fluctuating emission intensities through the multiple plasmonic modes of the junction are consistent with a finite number of randomly localized, point-like sources dominating the optoelectronic response. Contrasting with these microscopic fluctuations, the overall plasmonic and electronic functionalities of our devices feature long-term survival at room temperature and under an electrical bias of a few volts, allowing for measurements over several months.

Mode-Specific Coupling of Nanoparticle-on-Mirror Cavities with Cylindrical Vector Beams.

Nanocavities formed by ultrathin metallic gaps permit the reproducible engineering and enhancement of light-matter interaction, with mode volumes reaching the smallest values allowed by quantum mechanics. While the enhanced vacuum field in metallic nanogaps has been firmly evidenced, fewer experimental reports have examined the far-field to near-field input coupling under strongly focused laser beam. Here, we experimentally demonstrate selective excitation of nanocavity modes controlled by the polarization and frequency of the laser beam. We reveal mode selectivity by recording confocal maps of Raman scattering excited by cylindrical vector beams, which are compared to the known excitation near-field patterns. Our measurements reveal the transverse vs longitudinal polarization of the excited antenna mode and how the input coupling rate depends on laser wavelength. The method introduced here is easily applicable to other experimental scenarios, and our results help connect far-field with near-field parameters in quantitative models of nanocavity-enhanced phenomena.

Measurement-induced collective vibrational quantum coherence under spontaneous Raman scattering in a liquid.

Spontaneous vibrational Raman scattering is a ubiquitous form of light-matter interaction whose description necessitates quantization of the electromagnetic field. It is usually considered as an incoherent process because the scattered field lacks any predictable phase relationship with the incoming field. When probing an ensemble of molecules, the question therefore arises: What quantum state should be used to describe the molecular ensemble following spontaneous Stokes scattering? We experimentally address this question by measuring time-resolved Stokes-anti-Stokes two-photon coincidences on a molecular liquid consisting of several sub-ensembles with slightly different vibrational frequencies. When spontaneously scattered Stokes photons and subsequent anti-Stokes photons are detected into a single spatiotemporal mode, the observed dynamics is inconsistent with a statistical mixture of individually excited molecules. Instead, we show that the data are reproduced if Stokes-anti-Stokes correlations are mediated by a collective vibrational quantum, i.e. a coherent superposition of all molecules interacting with light. Our results demonstrate that the degree of coherence in the vibrational state of the liquid is not an intrinsic property of the material system, but rather depends on the optical excitation and detection geometry.

Neuronal growth on high-aspect-ratio diamond nanopillar arrays for biosensing applications.

Monitoring neuronal activity with simultaneously high spatial and temporal resolution in living cell cultures is crucial to advance understanding of the development and functioning of our brain, and to gain further insights in the origin of brain disorders. While it has been demonstrated that the quantum sensing capabilities of nitrogen-vacancy (NV) centers in diamond allow real time detection of action potentials from large neurons in marine invertebrates, quantum monitoring of mammalian neurons (presenting much smaller dimensions and thus producing much lower signal and requiring higher spatial resolution) has hitherto remained elusive. In this context, diamond nanostructuring can offer the opportunity to boost the diamond platform sensitivity to the required level. However, a comprehensive analysis of the impact of a nanostructured diamond surface on the neuronal viability and growth was lacking. Here, we pattern a single crystal diamond surface with large-scale nanopillar arrays and we successfully demonstrate growth of a network of living and functional primary mouse hippocampal neurons on it. Our study on geometrical parameters reveals preferential growth along the nanopillar grid axes with excellent physical contact between cell membrane and nanopillar apex. Our results suggest that neuron growth can be tailored on diamond nanopillars to realize a nanophotonic quantum sensing platform for wide-field and label-free neuronal activity recording with sub-cellular resolution.

Molecular Vibration Explorer: an Online Database and Toolbox for Surface-Enhanced Frequency Conversion and Infrared and Raman Spectroscopy.

We present Molecular Vibration Explorer, a freely accessible online database and interactive tool for exploring vibrational spectra and tensorial light-vibration coupling strengths of a large collection of thiolated molecules. The "Gold" version of the database gathers the results from density functional theory calculations on 2800 commercially available thiol compounds linked to a gold atom, with the main motivation to screen the best molecules for THz and mid-infrared to visible upconversion. Additionally, the "Thiol" version of the database contains results for 1900 unbound thiolated compounds. They both provide access to a comprehensive set of computed spectroscopic parameters for all vibrational modes of all molecules in the database. The user can simultaneously investigate infrared absorption, Raman scattering, and vibrational sum- and difference-frequency generation cross sections. Molecules can be screened for various parameters in custom frequency ranges, such as a large Raman cross-section under a specific molecular orientation, or a large orientation-averaged sum-frequency generation (SFG) efficiency. The user can select polarization vectors for the electromagnetic fields, set the orientation of the molecule, and customize parameters for plotting the corresponding IR, Raman, and sum-frequency spectra. We illustrate the capabilities of this tool with selected applications in the field of surface-enhanced spectroscopy.

Continuous-wave frequency upconversion with a molecular optomechanical nanocavity.

Coherent upconversion of terahertz and mid-infrared signals into visible light opens new horizons for spectroscopy, imaging, and sensing but represents a challenge for conventional nonlinear optics. Here, we used a plasmonic nanocavity hosting a few hundred molecules to demonstrate optomechanical transduction of submicrowatt continuous-wave signals from the mid-infrared (32 terahertz) onto the visible domain at ambient conditions. The incoming field resonantly drives a collective molecular vibration, which imprints a coherent modulation on a visible pump laser and results in upconverted Raman sidebands with subnatural linewidth. Our dual-band nanocavity offers an estimated 13 orders of magnitude enhancement in upconversion efficiency per molecule. Our results demonstrate that molecular cavity optomechanics is a flexible paradigm for frequency conversion leveraging tailorable molecular and plasmonic properties.

Structural Order of the Molecular Adlayer Impacts the Stability of Nanoparticle-on-Mirror Plasmonic Cavities.

Immense field enhancement and nanoscale confinement of light are possible within nanoparticle-on-mirror (NPoM) plasmonic resonators, which enable novel optically activated physical and chemical phenomena and render these nanocavities greatly sensitive to minute structural changes, down to the atomic scale. Although a few of these structural parameters, primarily linked to the nanoparticle and the mirror morphology, have been identified, the impact of molecular assembly and organization of the spacer layer between them has often been left uncharacterized. Here, we experimentally investigate how the complex and reconfigurable nature of a thiol-based self-assembled monolayer (SAM) adsorbed on the mirror surface impacts the optical properties of the NPoMs. We fabricate NPoMs with distinct molecular organizations by controlling the incubation time of the mirror in the thiol solution. Afterward, we investigate the structural changes that occur under laser irradiation by tracking the bonding dipole plasmon mode, while also monitoring Stokes and anti-Stokes Raman scattering from the molecules as a probe of their integrity. First, we find an effective decrease in the SAM height as the laser power increases, compatible with an irreversible change of molecule orientation caused by heating. Second, we observe that the nanocavities prepared with a densely packed and more ordered monolayer of molecules are more prone to changes in their resonance compared to samples with sparser and more disordered SAMs. Our measurements indicate that molecular orientation and packing on the mirror surface play a key role in determining the stability of NPoM structures and hence highlight the under-recognized significance of SAM characterization in the development of NPoM-based applications.

Intrinsic luminescence blinking from plasmonic nanojunctions.

Plasmonic nanojunctions, consisting of adjacent metal structures with nanometre gaps, can support localised plasmon resonances that boost light matter interactions and concentrate electromagnetic fields at the nanoscale. In this regime, the optical response of the system is governed by poorly understood dynamical phenomena at the frontier between the bulk, molecular and atomic scales. Here, we report ubiquitous spectral fluctuations in the intrinsic light emission from photo-excited gold nanojunctions, which we attribute to the light-induced formation of domain boundaries and quantum-confined emitters inside the noble metal. Our data suggest that photoexcited carriers and gold adatom - molecule interactions play key roles in triggering luminescence blinking. Surprisingly, this internal restructuring of the metal has no measurable impact on the Raman signal and scattering spectrum of the plasmonic cavity. Our findings demonstrate that metal luminescence offers a valuable proxy to investigate atomic fluctuations in plasmonic cavities, complementary to other optical and electrical techniques.

Bell correlations between light and vibration at ambient conditions.

Time-resolved Raman spectroscopy techniques offer various ways to study the dynamics of molecular vibrations in liquids or gases and optical phonons in crystals. While these techniques give access to the coherence time of the vibrational modes, they are not able to reveal the fragile quantum correlations that are spontaneously created between light and vibration during the Raman interaction. Here, we present a scheme leveraging universal properties of spontaneous Raman scattering to demonstrate Bell correlations between light and a collective molecular vibration. We measure the decay of these hybrid photon-phonon Bell correlations with sub-picosecond time resolution and find that they survive over several hundred oscillations at ambient conditions. Our method offers a universal approach to generate entanglement between light and molecular vibrations. Moreover, our results pave the way for the study of quantum correlations in more complex solid-state and molecular systems in their natural state.

Intravascular Ultrasound in the Endovascular Treatment of Patients With Peripheral Arterial Disease: Current Role and Future Perspectives.

Over the last decade, intravascular ultrasound (IVUS) has emerged as a useful adjunctive tool to angiography in an increasing number of catheter-based procedures for peripheral arterial disease (PAD). IVUS catheters offer accurate cross-sectional imaging of arterial vessels with high dimensional accuracy and provide accurate information about lesion morphology. IVUS enables assessment of the plaque morphology, vessel diameter, and the presence of arterial dissections. Furthermore, IVUS is able to properly guide the best choice of appropriate percutaneous transluminal angioplasty (PTA) technique, guide the delivery of different devices, and assess the immediate result of any endovascular intervention. In the present review, the role of IVUS for PAD will be discussed, specifically the applications of IVUS technology during interventional procedures including PTA, stent sizing, crossing total occlusion, assessing residual narrowing and stent apposition and expansion, and atherectomy. Future perspectives of IVUS-guided treatments and cost-effectiveness of the systematic use of IVUS during endovascular interventions will be also discussed.

Percutaneous Rotational Mechanical Atherectomy Plus Thrombectomy Using Rotarex S Device in Patients With Acute and Subacute Lower Limb Ischemia: A Review of Safety, Efficacy, and Outcomes.

Acute and subacute ischemia of lower limbs is associated with high risk of amputation and potential severe life-threatening complications. Despite a lack of clear therapeutic recommendations, surgical treatments such as thrombectomy or bypass and/or catheter-directed thrombolysis (CDT) have been first-line procedures in both acute and subacute limb ischemia, but each therapy may lead to significant morbidity and mortality. Such situations demand fast restoration of appropriate flow to preclude limb loss and other complications. Percutaneous mechanical atherectomy plus thrombectomy (MATH) represents a minimally invasive approach for quickly recanalizing thrombus-containing lesions whatever the age of thrombus. Indeed, many chronic patients can present with critical limb ischemia, with thrombus-containing occlusive lesions triggered by underlying atherosclerotic disease. MATH offers various advantages over surgery and CDT, with lower invasiveness, faster recanalization, and the possibility to immediately treat the underlying lesions, with a lower rate of bleeding complications and no need for intensive care unit stay. Currently, several mechanical thrombectomy devices are offered as an alternative therapy and can be divided into pure rotational MATH systems and rheolytic thrombectomy devices. The only pure rotational MATH device currently available on the market is the Rotarex S device. We aimed to review contemporary clinical data regarding the safety, efficacy, and outcomes of MATH therapy using Rotarex S catheter in acute and subacute thrombus-containing arterial lesions of lower limbs. Future perspectives of Rotarex S MATH treatment and cost-effectiveness of its routine use will be also discussed.

Single-Session Percutaneous Mechanical Thrombectomy Using the Aspirex®S Device Plus Stenting for Acute Iliofemoral Deep Vein Thrombosis: Safety, Efficacy, and Mid-Term Outcomes.

To assess the safety, efficacy and mid-term outcomes of single-session percutaneous mechanical thrombectomy (PMT) for acute symptomatic iliofemoral deep vein thrombosis (DVT) using the Aspirex®S device. Retrospective review of 30 patients (women, 23; mean age, 45.5 ± 19.9 years; range, 17-76) who underwent PMT with the 10-French Aspirex®S device (Straub Medical AG, Wangs, Switzerland) for acute DVT between December 2015 and March 2019. Procedures were performed by popliteal (n = 22) or jugular (n = 7) approach, or both (n = 1). Mean time from diagnosis to PMT was 5.5 ± 4.6 days (range, 2-11). Successful thrombus removal and venous patency restoration were achieved in all patients (100%). Fluid removal was 307.8 ± 66.1 mL (range, 190-410). Additional venous stenting rate was 100%. Mean procedural time was 107.3 ± 33.9 min (range, 70-180). No major complication occurred. The patient's postprocedural course was uneventful in all cases, with hospital discharge within 2 days in 83.3%. Early in-stent rethrombosis occurred within 1 week in 3 patients, successfully managed by endovascular approach. Secondary stent patency rate was 86.7% at a mean follow-up of 22.3 ± 14.2 months (range, 6-48), as assessed by Duplex ultrasound. Single-session of PMT using the Aspirex®S device is a safe and effective therapeutic option in patients presenting with acute symptomatic iliofemoral DVT.

Percutaneous mechanical atherothrombectomy using the Rotarex®S device in peripheral artery in-stent restenosis or occlusion: a French retrospective multicenter study on 128 patients.

BACKGROUND: To ascertain the safety and mid-term outcomes of Rotarex®S rotational atherectomy plus thrombectomy device (Straub Medical AG, Wangs, Switzerland) with or without adjunctive treatment (e.g., percutaneous transluminal angioplasty, PTA/drug-coated balloon, DCB/stenting) in patients with in-stent restenosis (ISR) or occlusion in the iliac and/or infrainguinal arteries. METHODS: French multicenter retrospective study of all patients treated by in-stent percutaneous mechanical debulking (PMD) of the lower limbs with Rotarex®S device between January 2013 and November 2018. RESULTS: The cohort consisted of 128 patients (88 men and 40 women), aged 39-94 years (mean, 66.7±12 years). All patients presented with cardio-vascular risk factors. Overall, 51.5% of patients had critical limb ischemia. The study demonstrated a technical success of 96.9% in the population with PMD and adjunctive PTA (95/128, 74.2%) or adjunctive DCB (16/128, 12.5%) or both (13/128, 10.2%). At 12-months follow-up, the primary clinical success/patency rate was 92.3% and the secondary clinical success/patency rate was 91.4%. Rate of limb salvage was 93.7%. Overall 32 (25%) reinterventions were reported with mean time from Rotarex®S treatment to reintervention of 7.1±8.2 months. Target lesion revascularization (TLR) was 19.5% (25/128). Seven (5.5%) patients developed distal embolism that responded to endovascular treatment. At mean follow-up, major adverse events (MAE) observed were death (18/128, 14.1%), myocardial infarction (MI) (9/128, 7.0%), stroke (2/128, 1.6%) and renal failure (3/128, 2.3%). CONCLUSIONS: Recanalization with Rotarex®S rotational atherectomy plus thrombectomy device is a practical choice for arterial ISR/occlusions of the iliac and/or infrainguinal arteries, regardless of the age of the thrombus, with satisfying TLR. Only adjunctive PTA is often necessary to further improve the recanalization.

Percutaneous ultrasound-guided balloon-assisted embolization of iatrogenic femoral artery pseudoaneurysms with Glubran®2 cyanoacrylate glue: safety, efficacy and outcomes.

BACKGROUND: Femoral pseudoaneurysm (PA) is a frequent complication of arterial access for endovascular procedures. Surgery has traditionally been considered as the gold standard of therapy. We aimed to report our experience of percutaneous ultrasound (US)-guided balloon-assisted embolization with cyanoacrylate glue for the treatment of iatrogenic femoral PAs. METHODS: Retrospective two-center study of patients with femoral iatrogenic PAs treated by N-butyl cyanoacrylate-methacryloxy sulfolane (NBCA-MS) Glubran®2 glue embolization between July 2013 and November 2017. All patients underwent contralateral arterial access with balloon placement of an appropriate size in front of the PA neck before glue/lipiodol embolization in a 1:1 ratio by percutaneous US-guided puncture of the aneurysmal sac under fluoroscopy control. RESULTS: Twenty-three patients (12 females, 11 males; median age, 79 years; range, 18-93 years) were included. Median PA size was 34 mm (range, 17-60 mm). The median time to treatment was 5 days (range, 1-30 days). Twenty patients (86.9%) were successfully treated by glue injection alone. The three remaining patients (13.1%) with persistent PA or associated arterial-venous fistula were immediately treated during the same procedure by additional stent-graft. Then, overall immediate and 1-month clinical success rates were 100%. No surgical conversion was necessary. No recurrence was reported during the median follow-up of 11 months (range, 2-73 months). Two (8.7%) puncture-related complications occurred at the contralateral arterial access site, which spontaneously resolved. No non-target glue embolization occurred. CONCLUSIONS: US-guided balloon-assisted glue embolization is safe and effective to treat iatrogenic femoral PAs in most cases, offering complete exclusion of the PA and avoiding the morbidity of open surgery.

Two-Color Pump-Probe Measurement of Photonic Quantum Correlations Mediated by a Single Phonon.

We propose and demonstrate a versatile technique to measure the lifetime of the one-phonon Fock state using two-color pump-probe Raman scattering and spectrally resolved, time-correlated photon counting. Following pulsed laser excitation, the n=1 phonon Fock state is probabilistically prepared by projective measurement of a single Stokes photon. The detection of an anti-Stokes photon generated by a second, time-delayed laser pulse probes the phonon population with subpicosecond time resolution. We observe strongly nonclassical Stokes-anti-Stokes correlations, whose decay maps the single phonon dynamics. Our scheme can be applied to any Raman-active vibrational mode. It can be modified to measure the lifetime of n≥1 Fock states or the phonon quantum coherences through the preparation and detection of two-mode entangled vibrational states.

Embolization with ethylene vinyl alcohol copolymer (Onyx®) for peripheral hemostatic and non-hemostatic applications: a feasibility and safety study.

BACKGROUND: Onyx® is a liquid embolic agent, which is approved for the treatment of cerebral vascular lesions but still rarely used in peripheral interventional radiology. The goal of this study is to report the feasibility and safety of embolization with Onyx® for peripheral hemostatic and non-hemostatic endovascular procedures. METHODS: Retrospective study of all consecutive patients who underwent visceral or peripheral embolization with Onyx® for hemostatic or non-hemostatic purpose in our department between May 2014 and November 2016. Demographic data, clinical presentation, underlying etiology, culprit vessel, endovascular procedure, pain during embolization, outcomes, and follow-up data were collected. RESULTS: Fifty patients (males, 34; females, 16; mean age, 56±18 years; range, 15-89 years) were included. Twenty-nine (58%) of patients underwent hemostatic embolization for arterial (n=22, 44%) or venous (n=7, 14%) bleeding lesions, whereas 21 (42%) of patients underwent non-hemostatic embolization for arterial aneurysms (n=8, 16%), preoperative portal vein deprivation (n=6, 12%) or other indications (n=7, 14%). Onyx-18 was used in 37 (74%) patients, Onyx-34 in 9 (18%) patients, and a combination of both in 4 (8%) patients. Onyx was used alone in 25 (50%) patients and in combination with other agent in 25 (50%) patients. Mean number of Onyx® vials used was 3.7 (range, 1-17). Immediate technical success rate was 100%. Primary clinical success was achieved in all patients. Recurrent bleeding occurred in two patients. Significant pain (pain score ≥3) was noted during injection in 10 (20%) patients. No major complication or side effects were noted within 1 month. CONCLUSIONS: Transcatheter embolization with Onyx® is feasible and safe in the peripheral arterial or venous vasculature for both bleeding and non-bleeding patients whatever the anatomic site.

Nonlinear characterization of a silicon integrated Bragg waveguide filter.

Bragg waveguides are promising optical filters for pump suppression in spontaneous four-wave mixing (FWM) photon sources. In this work, we investigate the generation of unwanted photon pairs in the filter itself. We do this by taking advantage of the relation between spontaneous and classical FWM, which allows for the precise characterization of the nonlinear response of the device. The pair generation rate estimated from the classical measurement is compared with the theoretical value calculated by means of a full quantum model of the filter, which also allows investigation of the spectral properties of the generated pairs. We find a good agreement between theory and experiment, confirming that stimulated FWM is a valuable approach to characterize the nonlinear response of an integrated filter, and that the pairs generated in a Bragg waveguide are not a serious issue for the operation of a fully integrated nonclassical source.