A5074382670- Advanced Fiber Laser Technologies
- Semiconductor Lasers and Optical Devices
- Photonic and Optical Devices
- Nonlinear Dynamics and Pattern Formation
- Spectroscopy and Laser Applications
- Nonlinear Photonic Systems
- Laser Design and Applications
- Laser-Matter Interactions and Applications
- Optical Network Technologies
- Semiconductor Quantum Structures and Devices
- Terahertz technology and applications
- Metamaterials and Metasurfaces Applications
- Neural Networks and Reservoir Computing
- Solid State Laser Technologies
- Photonic Crystals and Applications
- Advanced Fiber Optic Sensors
- Advanced Antenna and Metasurface Technologies
- Near-Field Optical Microscopy
- Mechanical and Optical Resonators
- Laser Material Processing Techniques
- Plasmonic and Surface Plasmon Research
- Slime Mold and Myxomycetes Research
- Optical Coherence Tomography Applications
- Nanofabrication and Lithography Techniques
- Random lasers and scattering media
Polytechnic University of Turin
2016-2025
Istituto di Fotonica e Nanotecnologie
2011-2023
Polytechnic University of Bari
2003-2021
University of Insubria
2004-2021
Harvard University
2021
Center for Nano Science and Technology
2021
Italian Institute of Technology
2021
Harvard University Press
2021
University of Brescia
2017
Istituto Nazionale di Fisica Nucleare, Sezione di Bari
2011-2016
We study the time dependence of optical power emitted by terahertz and mid-IR quantum cascade lasers in presence reinjection demonstrate unprecedented continuous wave (CW) emission stability for strong feedback. show that absence coherence collapse or other CW instabilities typical diode is inherently associated with high value photon to carrier lifetime ratio negligible linewidth enhancement factor lasers.
At terahertz (THz) frequencies, scattering-type scanning near-field optical microscopy (s-SNOM) based on continuous wave sources mostly relies cryogenic and bulky detectors, which represents a major constraint for its practical application. Here, we devise THz s-SNOM system that provides both amplitude phase contrast achieves nanoscale (60-70nm) in-plane spatial resolution. It features quantum cascade laser simultaneously emits frequency light senses the backscattered field through voltage...
Our ability to generate new distributions of light has been remarkably enhanced in recent years. At the most fundamental level, these patterns are obtained by ingeniously combining different electromagnetic modes. Interestingly, modal superposition occurs spatial, temporal as well spatio-temporal domain. This generalized concept structured is being applied across entire spectrum optics: generating classical and quantum states light, harnessing linear nonlinear light-matter interactions,...
Optical Frequency Comb (OFC) generated by semiconductor lasers are currently widely used in the extremely timely field of high capacity optical interconnects and precision spectroscopy. In last decade, several experimental evidences spontaneous OFC generation have been reported single section Quantum Dot (QD) lasers. Here we provide a physical understanding these self-organization phenomena simulating multi-mode dynamics Fabry-Perot (FP) QD laser using Time-Domain Traveling-Wave (TDTW) model...
Frequency combs have become a prominent research area in optics. Of particular interest as integrated comb technology are chip-scale sources, such semiconductor lasers and microresonators, which consist of resonators embedding nonlinear medium either with or without population inversion. Such active passive cavities were so far treated distinctly. Here we propose formal unification by introducing general equation that describes both types cavities. The also captures the physics hybrid...
Coupling is an essential mechanism that drives complexity in natural systems, transforming single, noninteracting elements into intricate networks with rich physical properties. Here, we demonstrate a chip-scale coupled laser system exhibits complex optical states impossible to achieve uncoupled system. We show pair of semiconductor ring lasers spontaneously forms frequency comb consisting the hybridized modes its cavity, exhibiting large number phase-locked tones anticross one another....
We theoretically consider infrared-driven hyperbolic metamaterials able to spatially filter terahertz (THz) radiation. The metamaterial is a slab made of alternating semiconductor and dielectric layers whose homogenized uniaxial response, at THz frequencies, shows principal permittivities different signs. gap provided by dispersion allows the stop spatial frequencies within bandwidth tunable changing infrared radiation intensity. numerically prove device functionality resorting full wave...
We study the instability thresholds of stationary emission a quantum cascade laser with optical feedback described by Lang Kobayashi model. introduce an exact linear stability analysis and approximated one for unipolar lasers, who does not exhibit relaxation oscillations, investigate regimes emitter beyond continuous wave threshold, depending on number density external cavity modes. then show that can coherent multimode oscillations indicate spontaneous phase-locking.
To monitor the density of photo-generated charge carriers on a semiconductor surface, we demonstrate detectorless imaging system based analysis optical feedback in terahertz quantum cascade lasers. Photo-excited free electron are created high resistivity n-type silicon wafers via low power (≅40 mW/cm2) continuous wave pump laser near infrared spectral range. A spatial light modulator allows to directly reconfigure and control photo-patterned intensity associated free-carrier distribution....
We experimentally demonstrate the existence of nondispersive solitary waves associated with a $2\ensuremath{\pi}$ phase rotation in strongly multimode ring semiconductor laser coherent forcing. Similarly to Bloch domain walls, such structures host chiral charge. The numerical simulations based on set effective Maxwell-Bloch equations support experimental evidence that only one sign charge is stable, which affects motion solitons. Furthermore, reduction model modified Ginzburg-Landau equation...
We cast a theoretical model based on effective semiconductor Maxwell-Bloch equations and study the dynamics of multi-mode mid-infrared quantum cascade laser in Fabry-Perot configuration with aim to investigate spontaneous generation optical frequency combs. This encompasses key features active medium, such as asymmetric, frequency-dependent gain refractive index well phase-amplitude coupling field provided by linewidth enhancement factor, some specific resonator features, spatial hole...
Near-field imaging techniques, at terahertz frequencies (1–10 THz), conventionally rely on bulky laser sources and detectors. Here, we employ a semiconductor heterostructure as THz source and, simultaneously, phase-sensitive detector, exploiting optical feedback interferometry combined with scattering near-field nanoscopy. We analyze the amplitude phase sensitivity of proposed technique function driving current attenuation, discussing operational conditions ideal to optimize nano-imaging...
In spatially extended Turing-unstable systems, parameter variation should, in theory, produce only fully developed patterns. experiment, however, localized patterns or solitons sitting on a smooth background often appear. Addition of nonlocal nonlinearity can resolve this discrepancy by tilting the "snaking" bifurcation diagram characteristic such problems.
The dynamics of a multimode Quantum Cascade Laser, is studied in model based on effective semiconductor Maxwell-Bloch equations, encompassing key features for the radiationmedium interaction such as an asymmetric, frequency dependent, gain and refractive index well phase-amplitude coupling provided by Henry factor.By considering role free spectral range factor, we develop criteria suitable to identify conditions which allow destabilize, close threshold, traveling wave emitted laser lead...
We consider the paraxial model for a nonlinear resonator with saturable absorber beyond mean-field limit. For accessible parametric domains we observe total radiation confinement and formation of 3D localized bright structures. Different from freely propagating light bullets, here self-organization proceeds feedback, combined diffraction nonlinearity. Such ``cavity'' bullets can be independently excited erased by appropriate pulses, once created, they endlessly travel cavity round-trip.
Abstract Nonlinear interactions in many physical systems lead to symmetry breaking phenomena which an initial spatially homogeneous stationary solution becomes modulated. Modulation instabilities have been widely studied since the 1960s different branches of nonlinear physics. In optics, they may result formation optical solitons, localized structures that maintain their shape as propagate, investigated ranging from fibres passive microresonators. Recently, a generalized version...
We present a numerical and analytical study of the self-detection scattering type near field optical microscopy (SD s-SNOM), recently demonstrated technique based on combination self-mixing interferometry near-field microscopy. This scheme, which exploits terahertz (THz) quantum cascade laser as both source detector, allows to investigate properties resonant materials in THz range with resolution far beyond diffraction limit. Our study, developed by using modified version Lang-Kobayashi...
We introduce a set of effective Maxwell-Bloch equations for broad area semiconductor lasers, and study the long-wavelength instability homogeneous solution. Unlike in two-level presence $\ensuremath{\alpha}$ factor allows us to observe this pattern forming even frequency domain where solution emission has lower threshold.