A5001947367- Spectroscopy and Laser Applications
- Advanced Fiber Laser Technologies
- Photonic and Optical Devices
- Terahertz technology and applications
- Semiconductor Lasers and Optical Devices
- Laser Design and Applications
- Atmospheric Ozone and Climate
- Cold Atom Physics and Bose-Einstein Condensates
- Digital Holography and Microscopy
- Mass Spectrometry Techniques and Applications
- Molecular Spectroscopy and Structure
- Laser-Matter Interactions and Applications
- Quantum Information and Cryptography
- Atomic and Subatomic Physics Research
- Advanced Chemical Physics Studies
- Advanced Frequency and Time Standards
- Mechanical and Optical Resonators
- Spectroscopy and Quantum Chemical Studies
- Semiconductor Quantum Structures and Devices
- Photonic Crystal and Fiber Optics
- Advanced Fluorescence Microscopy Techniques
- Optical Wireless Communication Technologies
- Optical Coherence Tomography Applications
- Atomic and Molecular Physics
- Adaptive optics and wavefront sensing
National Institute of Optics
2015-2024
European Theoretical Spectroscopy Facility
2022-2023
Nello Carrara Institute of Applied Physics
2022
Università Campus Bio-Medico
2021
Scuola Normale Superiore
2021
Istituto Nanoscienze
2021
European Laboratory for Non-Linear Spectroscopy
2011-2012
Abstract Coherent imaging in the THz range promises to exploit peculiar capabilities of these wavelengths penetrate common materials like plastics, ceramics, paper or clothes with potential breakthroughs non-destructive inspection and quality control, homeland security biomedical applications. Up now, however, coherent has been limited by time-consuming raster scanning, point-like detection schemes lack adequate sources. Here, we demonstrate real-time digital holography (DH) at frequencies...
We measure the absolute frequency of seven out nine allowed transitions between $2\text{ }^{3}S$ and }^{3}P$ hyperfine manifolds in a metastable $^{3}\mathrm{He}$ beam by using an optical comb synthesizer-assisted spectrometer. The relative uncertainty our measurements ranges from $1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}$ to $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}$, which is, knowledge, most precise result for any transition date. resulting...
The spectral purity of quantum cascade lasers (QCL) suggests their use in high-precision metrology applications at terahertz wavelengths. By combining a QCL with THz frequency comb, scientists have been able to measure the rotational transition gas (methanol) record-breaking precision four parts one billion.
We report on a set of high-sensitivity terahertz spectroscopy experiments making use QCLs to detect rotational molecular transitions in the far-infrared. demonstrate that using compact and transportable cryogen-free setup, based quantum cascade laser closed-cycle Stirling cryostat, pyroelectric detectors, considerable improvement sensitivity can be obtained by implementing wavelength modulation technique. Indeed, we show methanol vapour detection improved factor ≈ 4 with respect standard...
Miniaturized frequency comb sources across hard-to-access spectral regions, i.e. mid- and far-infrared, have long been sought. Four-wave-mixing based Quantum Cascade Laser combs (QCL-combs) are ideal candidates, in this respect, due to the unique possibility tailor their emission by proper nanoscale design of quantum wells. We demonstrate full-phase-stabilization a QCL-comb against primary standard, proving independent simultaneous control two degrees freedom (modes spacing offset) at...
Abstract Four-wave-mixing-based quantum cascade laser frequency combs (QCL-FC) are a powerful photonic tool, driving recent revolution in major molecular fingerprint regions, i.e. mid- and far-infrared domains. Their compact frequency-agile design, together with their high optical power spectral purity, promise to deliver an all-in-one source for the most challenging spectroscopic applications. Here, we demonstrate metrological-grade hybrid dual comb spectrometer, combining advantages of THz...
Difference frequency generation quantum cascade lasers are well-suited for applications requiring narrow-linewidth emitters.
We report on the development, testing, and performance analysis of a bow-tie resonant cavity for terahertz (THz) radiation, injected with continuous-wave 2.55 THz quantum cascade laser. The employs wire-grid polarizer as input/output coupler pair copper spherical mirrors coated an unprotected 500 nm thick gold layer. improvements respect to previous setups have led measured finesse value F=123, quality factor Q = 5.1x10^5. resonator performances relevant parameters are theoretically...
Abstract Broadband metrological‐grade frequency comb (FC) synthesizers with a rich number of phase locked modes are the ideal sources for quantum sensing and metrology. At terahertz (THz) frequencies, electrically pumped cascade lasers (QCLs) have shown quantum‐limited noise operation, phase/frequency absolute referencing self‐starting FC albeit over rather restricted dynamic range, governed by nature gain media that entangles group velocity dispersion at different bias points. Here,...
We report on the engineering of broadband quantum cascade lasers (QCLs) emitting at Terahertz (THz) frequencies, which exploit a heterogeneous active region scheme and have current density dynamic range (Jdr) 3.2, significantly larger than state-of-the-art, over 1.3 THz bandwidth. demonstrate that devised operate as optical frequency comb synthesizers, in continuous-wave, with maximum output power 4 mW (0.73 regime). Measurement intermode beatnote map reveals clear dispersion-compensated...
Abstract Broadband, quantum-engineered, quantum cascade lasers (QCLs) are the most powerful chip-scale sources of optical frequency combs (FCs) across mid-infrared and terahertz (THz) range. The inherently short intersubband upper state lifetime spontaneously allows mode proliferation, with large efficiencies, as a result intracavity four-wave mixing. QCLs can be easily integrated external elements or engineered for embedding nonlinear components operate detectors, providing an intriguing...
Terahertz quantum cascade laser sources based on intra-cavity difference frequency generation from mid-IR devices are an important asset for applications in rotational molecular spectroscopy and sensing, being the only electrically pumped device able to operate 0.6–6 THz range without need of bulky expensive liquid helium cooling. Here we present comb operation obtained by mixing a distributed feedback at λ = 6.5 μm Fabry–Pérot around 6.9 μm. The resulting ultra-broadband emission extends...
Since the beginning of this millennium, frequency comb generators have reshaped metrology and related areas. After more than two decades since their first realization, several other ways to generate combs, in any spectral region, been demonstrated, each way with its peculiar features. This trend has triggered need quantitatively assess how close new realizations are an ideal comb, a feature that will be called combness throughout paper. We briefly review very dynamic area novel sources we...
Abstract The increased demand for high‐speed (terabit‐per‐second) wireless data transmission has driven the shift of frequency carrier from ubiquitous radio systems toward 1–5 THz range, triggering a new interest quantum cascade laser (QCL)‐based free‐space optical (FSO) links. As compared to standard telecom‐band FSO links, platforms based on sources are inherently robust against Rayleigh scattering. Atmospheric absorption, mainly due water vapor, limits achievable link distance but at same...
The use of a high-electron mobility semiconductor nanowire as transistor channel has recently allowed the extension spectral coverage THz field-effect detectors up to 1.5 THz. In this report, we demonstrate efficient operation detector based on at much higher frequency, 2.8 THz, with responsivity ≈5 V/W in bandwidth ≈100 kHz, thus proving full potential such approach for detection quantum cascade lasers. Finally, sensing system is exploited perform raster scan transmission imaging, high...
We report on the evidence of saturation effects in a rotational transition CH3OH around 2.5 THz, induced by free-running continuous-wave quantum cascade laser (QCL). The QCL emission is used for direct-absorption spectroscopy experiments, allowing to study dependence absorption coefficient gas pressure and intensity. A intensity 25 μW/mm2, 17 μbar, measured. This result represents initial step towards implementation QCL-based high-resolution sub-Doppler THz spectroscopy, which expected...