A5007858488- Spectroscopy and Laser Applications
- Advanced Fiber Laser Technologies
- Laser Design and Applications
- Atmospheric Ozone and Climate
- Photonic and Optical Devices
- Atmospheric and Environmental Gas Dynamics
- Photorefractive and Nonlinear Optics
- Semiconductor Lasers and Optical Devices
- Analytical Chemistry and Sensors
- Laser-Matter Interactions and Applications
- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Mass Spectrometry Techniques and Applications
- Solid State Laser Technologies
- Spectroscopy and Quantum Chemical Studies
- Advanced Chemical Physics Studies
- Optical and Acousto-Optic Technologies
- Spectroscopy Techniques in Biomedical and Chemical Research
- Laser-induced spectroscopy and plasma
- Gas Sensing Nanomaterials and Sensors
- Astro and Planetary Science
- Terahertz technology and applications
- Atomic and Molecular Physics
- Advanced Frequency and Time Standards
- Advanced Fiber Optic Sensors
European Theoretical Spectroscopy Facility
2023
National Institute of Optics
2012-2022
National University of Engineering
2018
SAES Group (Italy)
2017
Interuniversity Consortium for Magnetic Resonance
2014
Istituto Nazionale per la Fisica della Materia
1996-2002
University of Florence
2002
Radiocarbon ((14)C) concentrations at a 43 parts-per-quadrillion level are measured by using saturated-absorption cavity ringdown spectroscopy exciting radiocarbon-dioxide ((14)C(16)O(2)) molecules the 4.5 μm wavelength. The ultimate sensitivity limits of molecular trace gas sensing pushed down to attobar pressures comb-assisted absorption setup. Such result represents lowest pressure ever detected for simple molecules. unique sensitivity, wide dynamic range, compactness, and relatively low...
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 novel approach to cavity ring-down spectroscopy with the sample gas in saturated-absorption regime. This technique allows us decouple and simultaneously retrieve empty-cavity background absorption signal, by means of theoretical model that we developed tested. The high sensitivity frequency precision for spectroscopic applications are exploited measure, first time, hyperfine structure an excited vibrational state 17O12C16O natural abundance accuracy few parts 10{-11}.
High-sensitivity radiocarbon detection has been, until now, a prerogative of accelerator mass spectrometry (AMS). Here we present compact and simple spectroscopic apparatus, based on saturated-absorption cavity ring-down, approaching the ultimate AMS sensitivity. We measure dioxide concentration down to few parts per quadrillion by use heterodyne-spectroscopy system with two quantum cascade lasers at 4.5 μm, reference cell, high-finesse sample gas cooled 170 K. Our results pave way paradigm...
We report on a spectroscopic technique named intracavity quartz-enhanced photoacoustic spectroscopy (I-QEPAS) employed for sensitive trace-gas detection in the mid-infrared spectral region. It is based combination of QEPAS with buildup optical cavity. The sensor includes distributed feedback quantum cascade laser emitting at 4.33 μm. achieved power factor ∼500, which corresponds to an ∼0.75 W. CO2 has been selected as target molecule I-QEPAS demonstration. sensitivity 300 parts per trillion...
The frequency-noise power spectral density of a room-temperature distributed-feedback quantum cascade laser emitting at λ = 4.36 μm has been measured. An intrinsic linewidth value 260 Hz is retrieved, in reasonable agreement with theoretical calculations. A noise reduction about factor 200 most the frequency interval also found, respect to cryogenic same wavelength. quantitative treatment shows that it can be explained by temperature-dependent mechanism governing transport processes resonant...
We report on the narrowing of a room-temperature mid-IR quantum cascade laser by frequency locking it to CO2 sub-Doppler transition obtained polarization spectroscopy. A bandwidth 250 kHz has been achieved. The linewidth is narrowed more than two orders magnitude below 1 kHz, and its absolute stabilized at same level.
We report on the linewidth narrowing of a room-temperature mid-infrared quantum cascade laser by phase-locking to difference-frequency-generated radiation referenced an optical frequency comb synthesizer. A locking bandwidth 250 kHz, with residual rms phase-noise 0.56 rad, has been achieved. The is narrowed more than 2 orders magnitude below 1 and its stabilized absolute traceability 2×10−12. This source allowed measurement CO2 molecular transition uncertainty about kHz.
An ultra-sensitive and selective quartz-enhanced photoacoustic spectroscopy (QEPAS) combined with a high-finesse cavity sensor platform is proposed as novel method for trace gas sensing. We call this technique Intra-cavity QEPAS (I-QEPAS). In the scheme, single-mode continuous wave quantum cascade laser (QCL) coupled into bow-tie optical cavity. The locked to QCL emission frequency by means of feedback-locking loop that acts directly on piezoelectric actuator mounted behind one mirrors. A...
We report what we believe to be the first absolute frequency measurement performed using a quantum-cascade laser (QCL) referenced an optical comb synthesizer (OFCS). A QCL at 4.43 μm has been used for producing near-infrared radiation 858 nm by means of sum-frequency generation with Nd:YAG source in periodically poled lithium niobate nonlinear crystal. The measured detecting beat note between sum and diode same wavelength, while both were OFCS. Doppler-broadened line profiles 13CO2 molecular...
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.
A narrow-linewidth comb-linked nonlinear source is used as master radiation to injection lock a room-temperature mid-infrared quantum cascade laser (QCL). This process leads direct of the QCL optical frequency comb, providing unique features narrow linewidth, absolute frequency, higher output power, and wide mode-hop-free tunability. The reproduces injected within more than 94%, with reduction frequency-noise spectral density by 3 4 orders magnitude up about 100 kHz, linewidth narrowing from...
We report on the generation of a frequency comb around 4330 nm with an unprecedented coherence single teeth. Generating within Ti:sapphire laser cavity by difference-frequency process and using phase-lock scheme based direct digital synthesis, we achieve tooth linewidth 2.0 kHz in 1-s timescale (750 Hz 20 ms). The generated per-tooth power 1 μW ranks this among best ever realized mid-infrared terms spectral density.
Abstract Optical frequency combs generated by quantum cascade lasers have recently been demonstrated in the mid and far infrared, but a detailed analysis of possibility fine control emission to use them for high‐resolution spectroscopy metrology applications is still missing. In this manuscript attempt stabilizing mid‐infrared laser comb (QCL‐comb) against metrological intracavity‐difference‐frequency‐generated through single phase‐locking chain acting on driving current presented. Following...
We demonstrate the possibility of extending well-established metrological performance optical frequency-comb synthesizers to mid-IR region by phase locking pump and signal lasers a difference-frequency source two near-IR teeth an comb. An uncertainty 800 Hz (1.1 x 10(-11)) in absolute frequencies CO2 transitions near 4.2 microm has been measured cavity-enhanced saturated-absorption spectroscopy. Prospects for creation new dense set high-quality molecular frequency standards IR are discussed.
We report on a new coherent source that, using phase-lock scheme to an optical frequency-comb synthesizer, achieves 10-Hz intrinsic linewidth, is tunable from 4 4.5 microm with presettable absolute frequency and, when coupled high-finesse cavity, can provide short-term absorption sensitivity of 1.3 x 10(-11) cm(-1)Hz,(-1/2). These unique spectral features make this precise tool for molecular physics.
A cw mid-IR coherent source based on difference-frequency generation is designed and characterized. For generation, a periodically poled MgO:LiNbO(3) crystal placed inside compact Ti:sapphire laser cavity. This provides high-power pump radiation for the nonlinear process. Optical injection by an external-cavity diode ensures single-frequency operation of laser, while signal provided fiber-amplified Nd:YAG laser. Mid-IR can be generated with 3850-4540 nm tuning range, narrow linewidth,...
By measuring the frequency-noise power spectral density of a cryogenically-cooled mid-infrared quantum cascade laser, we investigate different contributions to noise spectrum and identify main differences with respect standard bipolar semiconductor devices. In particular, existence thermal cut-off on <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">${1/f}$</tex></formula> allows current fluctuations...
We report on the experimental demonstration of metrological and spectroscopic performances a mid-infrared comb generated by nonlinear downconversion process from Ti:sapphire-based near-infrared comb. A quantum cascade laser at 4330 nm was phase-locked to single tooth this its frequency-noise power spectral density measured. The itself also used as multifrequency highly coherent source perform ambient air direct spectroscopy with Vernier technique, demultiplexing it high-finesse Fabry-Perot cavity.
The first results of an optical method for measuring radiocarbon concentrations, based on mid-infrared laser spectroscopy a carbon dioxide gas sample, are presented with the theoretical bases explained in detail. measurements modern and highly enriched samples show extreme linearity this technique over more than 5 decades. An intercomparison accelerator mass spectrometry (AMS) is performed both 14 C-dead samples, assessing almost perfect agreement their respectively measured concentration...