Read by QxMD icon Read


L Carletti, D Rocco, A Locatelli, C De Angelis, V F Gili, M Ravaro, I Favero, G Leo, M Finazzi, L Ghirardini, M Celebrano, G Marino, A V Zayats
We review recent achievements in the field of nanoscale nonlinear AlGaAs photonics based on all-dielectric optical antennas. After discussing the motivation and main technological challenges for the development of an AlGaAs monolithic platform for χ ((2)) nonlinear nanophotonics, we present numerical and experimental investigations of the second-order nonlinear response and physical reasons for high efficiency of second-order nonlinear interactions in the AlGaAs nano-antennas. In particular, we emphasize the role of the dipolar resonances at the fundamental frequency and the multipolar resonances at the second harmonic wavelength...
February 16, 2017: Nanotechnology
L Ghirardini, L Carletti, V Gili, G Pellegrini, L Duò, M Finazzi, D Rocco, A Locatelli, C De Angelis, I Favero, M Ravaro, G Leo, A Lemaître, M Celebrano
Manipulating light at the nanoscale by means of dielectric nanoantennas recently received renewed attention thanks to the development of key enabling fabrication tools in semiconductor technology, combined with the extremely low losses exhibited by dielectrics in the optical regime. Nanostructures based on III-V type semiconductors, characterized by an intrinsic broken symmetry down to a single elementary cell, has already demonstrated remarkable nonlinear conversion efficiencies at scales well below the operating wavelength...
February 1, 2017: Optics Letters
Leandro P Ravaro, Tiago R Almeida, Rodrigo Q Albuquerque, Andrea S S de Camargo
The polynuclear complex Cu4 I4 py4 has been largely studied in solution and in the powder form due to its interesting luminescent properties, which are largely dependent on temperature and pressure. In this work, we present the synthesis of the complex and its wet impregnation in a mesoporous silica host obtained by sol-gel methodology. For optimized loadings, the well-dispersed guest molecules exhibit strong interaction with molecular oxygen, resulting in a significant quenching of the luminescence. The process is highly reversible with a Stern-Volmer constant of Ksv = 33...
November 28, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
G L Seravalle, G Brambilla, R Dell'Oro, F Quarti Trevano, D Prata Pizzala, S Ravaro, G Mancia, G Grassi
OBJECTIVE: It is unknown whether and to what extent antihypertensive drug treatment capable to reduce adrenergic overactivity normalizes cardiovascular sympathetic drive. DESIGN AND METHOD: Results of three studies carried out by our group assessing muscle sympathetic nerve traffic (MSNA) via the microneurographic technique were analyzed, comparing the data obtained after long-term combination drug treatment with ACE-inhibitors, diuretics and calcium channel blockers with those detected in 30 age-matched untreated healthy normotensive controls (C)...
September 2016: Journal of Hypertension
Massimiliano Locatelli, Marco Ravaro, Saverio Bartalini, Luigi Consolino, Miriam S Vitiello, Riccardo Cicchi, Francesco Pavone, Paolo De Natale
Coherent imaging in the THz range promises to exploit the peculiar capabilities of these wavelengths to penetrate common materials like plastics, ceramics, paper or clothes with potential breakthroughs in non-destructive inspection and quality control, homeland security and biomedical applications. Up to now, however, THz coherent imaging has been limited by time-consuming raster scanning, point-like detection schemes and by the lack of adequate coherent sources. Here, we demonstrate real-time digital holography (DH) at THz frequencies exploiting the high spectral purity and the mW output power of a quantum cascade laser combined with the high sensitivity and resolution of a microbolometric array...
2015: Scientific Reports
A Campa, L Consolino, M Ravaro, D Mazzotti, M S Vitiello, S Bartalini, P De Natale
We report on the realization and characterization of two different designs for resonant THz cavities, based on wire-grid polarizers as input/output couplers, and injected by a continuous-wave quantum cascade laser (QCL) emitting at 2.55 THz. A comparison between the measured resonators parameters and the expected theoretical values is reported. With achieved quality factor Q ≈ 2.5 × 10(5), these cavities show resonant peaks as narrow as few MHz, comparable with the typical Doppler linewidth of THz molecular transitions and slightly broader than the free-running QCL emission spectrum...
February 9, 2015: Optics Express
M Ravaro, M Locatelli, E Pugliese, I Di Leo, M Siciliani de Cumis, F D'Amato, P Poggi, L Consolino, R Meucci, P Ferraro, P De Natale
Mid-infrared digital holography based on CO2 lasers has proven to be a powerful coherent imaging technique due to reduced sensitivity to mechanical vibrations, increased field of view, high optical power, and possible vision through scattering media, e.g., smoke. Here we demonstrate a similar and more compact holographic system based on an external cavity quantum cascade laser emitting at 8 μm. Such a setup, which includes a highly sensitive microbolometric camera, allows the acquisition of speckle holograms of scattering objects, which can be processed in real time...
August 15, 2014: Optics Letters
M Ravaro, S Barbieri, G Santarelli, V Jagtap, C Manquest, C Sirtori, S P Khanna, E H Linfield
We report the measurement of the frequency noise power spectral density of a quantum cascade laser emitting at 2.5THz. The technique is based on heterodyning the laser emission frequency with a harmonic of the repetition rate of a near-infrared laser comb. This generates a beatnote in the radio frequency range that is demodulated using a tracking oscillator allowing measurement of the frequency noise. We find that the latter is strongly affected by the level of optical feedback, and obtain an intrinsic linewidth of ~230Hz, for an output power of 2mW...
November 5, 2012: Optics Express
M Ravaro, C Manquest, C Sirtori, S Barbieri, G Santarelli, K Blary, J-F Lampin, S P Khanna, E H Linfield
We report the heterodyne detection and phase locking of a 2.5 THz quantum cascade laser (QCL) using a terahertz frequency comb generated in a GaAs photomixer using a femtosecond fiber laser. With 10 mW emitted by the QCL, the phase-locked signal at the intermediate frequency yields 80 dB of signal-to-noise ratio in a bandwidth of 1 Hz.
October 15, 2011: Optics Letters
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"