A5059357510- Spectroscopy and Laser Applications
- Atmospheric Ozone and Climate
- Laser Design and Applications
- Advanced Fiber Laser Technologies
- Calibration and Measurement Techniques
- Atmospheric and Environmental Gas Dynamics
- Scientific Measurement and Uncertainty Evaluation
- Atomic and Subatomic Physics Research
- Chemical Thermodynamics and Molecular Structure
- Advanced Frequency and Time Standards
- Photonic and Optical Devices
- Analytical Chemistry and Sensors
- Machine Learning in Materials Science
- Water Quality Monitoring and Analysis
- Semiconductor Lasers and Optical Devices
- Laser-induced spectroscopy and plasma
- Advanced Thermodynamics and Statistical Mechanics
- Research Data Management Practices
- History and advancements in chemistry
- Radiomics and Machine Learning in Medical Imaging
- Digital Transformation in Industry
- Advanced X-ray and CT Imaging
- Advanced Chemical Physics Studies
- Cold Atom Physics and Bose-Einstein Condensates
- Surface and Thin Film Phenomena
University of Campania "Luigi Vanvitelli"
2014-2024
Azienda Ospedaliera Universitaria Università degli Studi della Campania Luigi Vanvitelli
2017-2024
National Institute of Optics
2004-2015
Istituto di Fotonica e Nanotecnologie
2015
Politecnico di Milano
2015
Istituto Nazionale di Fisica Nucleare
2015
University of Naples Federico II
2001-2014
Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
2003-2013
National Interuniversity Consortium for the Physical Sciences of Matter
2006-2012
Istituto Nazionale per la Fisica della Materia
2001
A comprehensive investigation of the frequency-noise spectral density a free-running midinfrared quantum-cascade laser is presented for first time. It provides direct evidence leveling this noise down to white-noise plateau, corresponding an intrinsic linewidth few hundred hertz. The experiment in agreement with most recent theory on fundamental mechanism line broadening lasers, which new insight into Schawlow-Townes formula and predicts narrowing beyond limit set by radiative lifetime upper level.
We report on a new implementation of Doppler broadening thermometry based precision absorption spectroscopy by means pair offset-frequency locked extended-cavity diode lasers at 1.39 μm. The method consists in the highly accurate observation shape 4(4,1)→4(4,0) line H2(18)O ν1+ν3 band, water vapor sample thermodynamic equilibrium. A sophisticated and extremely refined spectral analysis procedure is adopted for retrieval width as function gas pressure, taking into account Dicke narrowing...
We report on a new optical implementation of primary gas thermometry based laser-absorption spectrometry in the near infrared. The method consists retrieving Doppler broadening from highly accurate observations line shape $R(12)$ ${\ensuremath{\nu}}_{1}+2{\ensuremath{\nu}}_{2}^{0}+{\ensuremath{\nu}}_{3}$ transition ${\mathrm{CO}}_{2}$ at thermodynamic equilibrium. width measurements as function temperature, ranging between triple point water and gallium melting point, allowed for...
Complementary tests of the partially correlated speed-dependent Keilson-Storer (pCSDKS) model for shape isolated transition pure water vapor [N. H. Ngo et al., J. Chem. Phys. 136, 154310 (2012)]10.1063/1.4704675 are made using new measurements. The latter have been recorded a high sensitivity cavity ring down spectrometer, seven self-broadened H2O lines in 1.6 μm region at room temperature and pressures from 0.5 to 15 Torr. Furthermore, H218O spectra [M. D. De Vizia Rev. A 83, 052506...
We present a fully ab initio model and calculations of the spectral shapes absorption lines in pure molecular gas under conditions where influences collisions Doppler effect are significant. Predictions time dependence dipole autocorrelation functions (DACFs) made for CO${}_{2}$ at room temperature using requantized classical dynamics simulations. These carried, free any adjusted parameter, on basis an accurate anisotropic intermolecular potential. The Fourier-Laplace transforms these DACFs...
Launched in 2011 within the European Metrology Research Programme (EMRP) of EURAMET, joint research project "MeteoMet -Metrology for Meteorologyis
The International Committee for Weights and Measures (CIPM), at its meeting in October 2017, followed the recommendation of Consultative Units (CCU) on redefinition kilogram, ampere, kelvin mole. For kelvin, Boltzmann constant will be fixed with numerical value 1.380 649 × 10
The frequency of a DFB quantum cascade laser (QCL) emitting at 4.3 microm has been long-term stabilized to the Lamb-dip center CO2 ro-vibrational transition by means first-derivative locking saturated absorption signal. Thanks non-linear sum-frequency generation (SFG) process with fiber-amplified Nd:YAG laser, QCL mid-infrared (IR) radiation linked an optical frequency-comb synthesizer (OFCS) and its absolute counted kHz-level precision overall uncertainty 75 kHz.
An intensity-stabilized diode laser absorption spectrometer was developed and used to perform a highly accurate study of the line shape CO(2) lines, in spectral region around 5000 cm(-1), belonging nu(1) + 2nu(2)(0) nu(3) combination band, at temperature 296.00 K. Standard complex semiclassical models, including Dicke narrowing speed-dependent broadening effects, were applied, tested, compared pressure range between 0.7 4 kPa, order single out model best reproducing profile and, hence,...
The absorption line shape of a given ${\mathrm{H}}_{2}$$^{18}\mathrm{O}$ vibration-rotation at 1.38 $\ensuremath{\mu}$m was deeply investigated using spectroscopic approach based upon the use pair offset-frequency locked extended-cavity diode lasers. This dual-laser apparatus ensures extreme levels accuracy in controlling and measuring any variation laser frequency around absolute reference. As result, high precision were reached observation molecular near infrared. A variety semiclassical...
The technique of frequency-stabilized comb-calibrated cavity ring-down spectroscopy was used to observe the weak R(1) transition deuturated molecular hydrogen (HD) first overtone band in near infrared. Like hydrogen, HD is a benchmark system test quantum electrodynamics, looking for new physics beyond standard model. spectral line shape measured with an extremely high fidelity at relatively low gas pressures. use very refined line-shape model allowed us retrieve unperturbed line-center...
This work presents a very simple yet effective way to obtain direct referencing of quantum-cascade-laser at 4.3 μm near-IR frequency-comb. Precise tuning the comb repetition-rate allows be scanned across absorption lines CO2 gaseous sample and line profiles acquired with extreme reproducibility accuracy. By averaging over 50 acquisitions, line-centre frequencies are retrieved an uncertainty 30 kHz in linear interaction regime. The extension this methodology other molecules, by use widely...
We report on the development, characterization, and test of a comb-locked cavity ring-down spectrometer (CL-CRDS) operating in spectral region around 1.39 µm. The system is based use hemispherical optical resonator with finesse as high ∼507000, which gives an empty-cavity time about 285 µs. An Allan-Werle analysis repeated acquisitions at fixed laser frequency suggests minimum detectable absorption coefficient 2×10 −12 cm −1 for optimum integration 45 s. This limit can be exceeded by...
A robust phase-lock of a quantum-cascade-laser to near-infrared frequency-comb allows absorption spectra CO2 gas sample be acquired at different pressures with extreme repeatability and accuracy by tuning the repetition-rate comb, thus ensuring an absolute frequency scale on spectra. The method proves useful retrieve traceable spectroscopic parameters such as line-center frequencies, line intensity factors, pressure shift, broadening coefficients, unprecedented quality from metrological point view.
A laser absorption technique, based upon a pair of offset-frequency-locked extended-cavity diode lasers, was employed to perform line-shape measurements for ${\mathrm{H}}_{2}{}^{18}\mathrm{O}$ vibration-rotation transitions at 1.38 $\ensuremath{\mu}$m, with an extremely high spectral fidelity. This important feature mostly ensured by the highly accurate, absolute, and repeatable frequency axis characterizing each acquired spectrum. We present outcomes specific study speed dependence...
We implemented an optical frequency standard based on noise-immune cavity-enhanced heterodyne molecular spectroscopy (NICE-OHMS) at 1.39 μm. The emission of extended-cavity diode laser was actively stabilized against the center 4(4,1)→4(4,0) transition H(2)(18)O ν1+ν3 band, under saturation conditions. nonlinear regime laser-gas interaction reached by using cavity with a finesse about 8700. By filling it 18O-enriched water sample pressure few Pa, Lamb dip could be observed full width...
We report on complementary tests and measurements regarding our recent determination of the Boltzmann constant, kB, by means Doppler broadening thermometry, also providing additional information as compared to previous articles. A revised uncertainty budget is illustrated, including some new components that were ignored in spectroscopic experiments, better quantifying other estimated be negligible. In particular, we consider relativistic effect, perturbation caused finite bandwidth detection...
Previous research effort towards the determination of Boltzmann constant has significantly improved supporting theory and experimental practice several primary thermometry methods based on measurement a thermodynamic property macroscopic system at temperature triple point water. Presently, experiments are under way to demonstrate their accuracy in T over an extended range spanning interval between few kelvin copper freezing (1358 K). We discuss how these activities will improve link as...
We report on the improved determination of center frequency a hydrogen deuteride vibration-rotation transition. As result refined analysis cavity ring-down absorption spectra, it was possible to quantify influence hyperfine structure line weak 2-0 $R(1)$ line, as retrieved in Doppler-limited regime. It turns out that ignoring leads an underestimation about 350 kHz. The updated gives absolute centroid 217 105 181.936 MHz with global uncertainty 76
An intensity-stabilized laser absorption spectrometer, which incorporates a mirror-extended cavity diode laser, temperature-stabilized gas cell, and Michelson interferometer, was developed applied to highly accurate investigation of line intensity factors within the nu(1)+2nu(2) (0)+nu(3) combination band carbon dioxide, around 2 microm wavelength, at temperature 296.0 K. This relatively complex apparatus enables one observe shape with high precision accuracy in such way that it is possible...
We describe a continuous-wave diode laser spectrometer for water-vapour precision spectroscopy at 1.38 μm.The is based upon the use of simple scheme offset-frequency locking pair extended-cavity lasers that allows to achieve high levels accuracy and reproducibility in measuring molecular absorption.When locked master with an offset frequency 1.5 GHz, slave exhibits residual fluctuations ∼ 1 kHz over time interval 25 minutes, 1-s integration time.The could be continuously tuned up 3 scan...
We report on the outcomes of a specific study quadratic approximation in partially correlated speed-dependent hard-collision (pC-SDHC) model, which is currently recommended profile to replace Voigt convolution for shape an isolated line, when perturbed by neutral gas-phase molecules. In particular, we compared with hypergeometric dependence collisional relaxation rate absorber velocity using high-quality ${\mathrm{H}}_{2}^{18}\mathrm{O}$ absorption spectra, coincidence three...
Line intensities for carbon dioxide are measured with a novel spectroscopic approach, assisted by an optical frequency comb synthesizer calibration purposes. The main feature of the spectrometer consists in exploitation feedback from V-shaped high-finesse resonator to effectively narrow distributed diode laser at wavelength 2 μm. Laser-gas interaction takes place inside isothermal cell, which is placed on transmission cavity. High quality, self-calibrated, absorption spectra observed pure...