A5041387278- Photonic and Optical Devices
- Advanced Fiber Laser Technologies
- Advanced Fiber Optic Sensors
- Spectroscopy and Laser Applications
- Mechanical and Optical Resonators
- Laser Design and Applications
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Semiconductor Lasers and Optical Devices
- Analytical Chemistry and Sensors
- Particle Detector Development and Performance
- Particle physics theoretical and experimental studies
- Geophysics and Sensor Technology
- Plasmonic and Surface Plasmon Research
- Radiation Detection and Scintillator Technologies
- Quantum Electrodynamics and Casimir Effect
- Atomic and Subatomic Physics Research
- High-Energy Particle Collisions Research
- Photorefractive and Nonlinear Optics
- Cosmology and Gravitation Theories
- Optical and Acousto-Optic Technologies
- Photonic Crystal and Fiber Optics
- Advanced MEMS and NEMS Technologies
- Acoustic Wave Resonator Technologies
- Advanced Frequency and Time Standards
National Institute of Optics
2015-2024
National Research Council
2013-2024
Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
1997-2024
University of Genoa
2019-2023
Istituto Nazionale di Fisica Nucleare, Sezione di Genova
2008-2019
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
2018
Queen's University
2010
European Laboratory for Non-Linear Spectroscopy
2002-2007
Consorzio Roma Ricerche
2006
Istituto Nazionale per la Fisica della Materia
2000-2002
The measurement of relative displacements and deformations is important in many fields such as structural engineering, aerospace, geophysics, nanotechnology. Optical-fiber sensors have become key tools for strain measurements, with sensitivity limits ranging between 10(-9) 10(-6)ε hertz (Hz)(-1/2) (where ε the fractional length change). We report on measurements at 10(-13)ε-Hz(-1/2) level using a fiber Bragg-grating resonator diode-laser source that stabilized against quartz-disciplined...
Liquid droplets suspended by the tip of a thin wire, glass capillary, or needle form high-Q optical resonators, thanks to surface tension. Under gravity equilibrium conditions, maximum drop diameter is approximately 1.5 mm for paraffin oil (volume ∼ 0.5 μL) using, instance, silica fiber with 250 μm thickness. Whispering gallery modes are excited free-space near-infrared laser that frequency locked cavity resonance. The droplet serves as miniature laboratory sensing chemical species and...
This paper reports proof-of-principle of an optical fiber Bragg grating (FBG) operating as electric field sensor. The system is based on a semiconductor diode laser, emitting around 1577.5 nm that interrogates the sensor its maximum reflectivity point. application strong causes small variation path length waveguide due to electrostriction and thus perturbs peak wavelength. Calibration dynamic range tests are performed using parallel-plate capacitor create variable (1–100 kV/cm). A great...
An optical frequency synthesizer (OFS), based on difference- generation (DFG), is demonstrated at 3 µm. By mixing a near-infrared (IR) OFS and tunable continuous-wave (CW) laser in periodically poled lithium-niobate (PPLN) crystal, new comb created from 2.9 to 3.5 µm (in 180 nm wide spans) with 100 MHz mode spacing. phase-locking, the pump near-IR OFS, mid-IR directly linked Cs primary standard via global positioning system (GPS) time receiver. Then, compactness of our fibre-based set-up...
We report on a proof-of-principle work aimed at the development of fast-response fiber-optic accelerometers for seismic monitoring. The system is based semiconductor diode-laser source that interrogates newly devised two-dimensional inertial sensor suitable measurement horizontal ground accelerations. Plane acceleration components sensor's mass are detected by two fiber Bragg gratings anchored to its structure. Calibration and comparison with commercial accelerometer presented. A great...
We present a quasi-static fiber optic strain sensing system capable of resolving signals below nanostrain from 20 mHz. A telecom-grade distributed feedback CW diode laser is locked to Fabry-Perot sensor, transferring the detected onto laser. An H(13)C(14)N absorption line then used as frequency reference extract accurate low-frequency system.
We report the theoretical description and experimental demonstration of an optical resonator formed by inserting a Fiber Bragg Grating (FBG) in closed fiber loop.The spectral characteristics such strongly depend on reflectivity FBG.In wavelength region where FBG R is negligible, system behaves like conventional ring resonator.On other hand, when not vanishing, split-mode structure can be observed, associated to degeneracy removal two counterpropagating resonant modes.The magnitude mode...
The goal of the Archimedes experiment is to investigate role interaction between vacuum fluctuations and gravitational field. This will be possible thanks a high sensitivity cryogenic balance installed in SarGrav laboratory Sos Enattos mine (Sardinia), Italian candidate site for third generation wave observatory Einstein Telescope. measure small weight variations induced two temperature superconductors that have property “trapping” or “expelling” energy when their temperatures are greater...
A novel diode laser spectrometer was developed using dualwavelength multiplexing, ensuring ideal conditions for high-precision and simultaneous measurements of the 2H/1H, 17O/16O, 18O/16O isotope ratios in water. 1.4-m probed a H16OH / HO2H line pair near 7198 cm-1, while similar observed H16OH, H17OH, H18OH rovibrational lines around 7183 or 7200 cm-1. The 1-sigma standard deviation is 0.2 per thousand 18O/16O, 0.5 2H/1H 17O/16O ratios. Preliminary experiments with repeated injections...
We demonstrate the possibility of using radio-frequency modulation spectroscopic techniques for interrogation fiber Bragg-grating (FBG) structures. Sidebands at 2 GHz are superimposed onto output spectrum a 1560-nm DFB diode laser. The power reflected by an FBG is demodulated multiples sideband frequency. sideband-to-carrier beat signal shown to be extremely sensitive Bragg wavelength shifts due mechanical stress. Using this method, both static and dynamic strain measurements can performed,...
A 3-microm continuous-wave difference-frequency source is directly referenced to a mid-infrared optical frequency comb synthesizer by measuring their beat-note signal fast HgCdTe detector. Absolute metrology of molecular vibration spectra demonstrated locking the coherent radiation nearest tooth and tuning mode spacing across Doppler-broadened absorption profile CH(4) ro-vibrational transition.
Abstract Liquid droplet whispering-gallery-mode microresonators open a new research frontier for sensing, optomechanics and photonic devices. At visible wavelengths, where most liquids are transparent, major contribution to optical quality factor is expected theoretically from thermal surface distortions capillary waves. Here, we investigate experimentally these predictions using transient cavity ring-down spectroscopy. With our scheme, the out-coupling intrinsic loss measured independently...
Liquid droplets are ubiquitous in nature wherein surface tension shapes them into perfect spheres with atomic-scale smooth surfaces. Here, we use stable that cohost equatorial acoustical and optical resonances phase matched to enable the exchange of energy momentum between sound light. Relying on free-space laser excitation multiple whispering-gallery modes, harness a triple-resonant forward Brillouin scattering stimulate optomechanical waves. Nonlinear amplification droplet vibrations 60-70...
We investigated the spectrum of ${}^{16}{\mathrm{O}}_{2}$ molecule by high-sensitivity laser spectroscopy and searched for transitions involving states which are antisymmetric under exchange nuclei. These forbidden symmetrization postulate quantum mechanics. This is first reported experiment to test integer-spin particles high precision. Our data set an upper limit $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ a possible violation this postulate.
A low-noise transducer based on a fiber Fabry-Perot (FFP) cavity was used as pickup for an acoustic guitar.A distributed feedback (DFB) laser locked to 25 MHz-wide resonance of the FFP using Pound-Drever-Hall method.The correction signal audio output and preamplified sampled at up 96 kHz.The system is largely immune against optical noise sources, exhibits flat frequency response from infrasound region about kHz, has distortion-free range 50 dB.
We report on a method for surface plasmon resonance (SPR) refractive index sensing based direct time-domain measurements. An optical resonator is built around an SPR sensor, and its photon lifetime measured as function of loss induced by variations. The does not rely any spectroscopic analysis or intensity measurement. Time-domain measurements are practically immune to light fluctuations thus lead high resolution. A proof concept experiment carried out in which sensor response liquid samples...
In this paper we theoretically investigate a ring resonant cavity obtained by closing on itself π-shifted fiber Bragg grating, to be used for refractive index sensing applications. Differently from conventional the spectral structure of is characterized an asymmetric splitting doublet composed right side resonance having Fano profile and left symmetric Lorentzian profile. The shows narrower sharper peak than all other kinds achievable with both resonators gratings. A reduction linewidth...
In this paper, we report on theoretical investigation of split mode resonant sensors based fiber Bragg grating (FBG) ring resonators and π-shifted (π-FBG) resonators. By using a resonator (π-FBGRR) instead conventional (FBGRR), the symmetric antisymmetric resonance branches (i.e., eigen-modes perturbed system) show peculiar very important features that can be exploited to improve performance optic spectroscopic sensors. particular, π-FBGRR branch taylored have maximum splitting sensitivity...
We demonstrate a strain sensor with very high sensitivity in the static and low frequency regime based on fiber ring cavity that includes π phase-shifted Bragg grating. The grating acts as partial reflector couples two counter-propagating modes, generating splitting of resonant frequencies. presence sharp transition within grating's spectral transmittance makes this extremely sensitive to length, temperature, refractive index region where is written. variations caused by small mechanical...
Abstract In optics, whispering gallery modes (WGMs) are of light that arise in cylindrically symmetric structures. Their intensity profile is strongly confined around the interface structure, and their Q‐factors some highest ever measured with light. Here, physical mechanisms governing coupling a tangential beam into WGM microsphere analytically demonstrated. For that, Mie theory symmetries made use of. It demonstrated mechanism not related to any evanescent tunnelling effect. Rather, it...