A. Ruffini
University of Pisa
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Publication
Featured researches published by A. Ruffini.
Jetp Letters | 2001
A. N. Naumov; F. Giammanco; D. A. Sidorov-Biryukov; A. B. Fedotov; Paolo Marsili; A. Ruffini; A. M. Zheltikov
Coherent four-wave mixing (FWM) of laser pulses in gas-filled hollow fibers is studied. The experimental data and the expressions derived for the amplitude of the FWM signal indicate that the excitation of higher order waveguide modes is an important physical factor having a considerable influence on nonlinear optical processes in hollow fibers.
Journal of Experimental and Theoretical Physics | 2001
A. N. Naumov; D. A. Sidorov-Biryukov; A. B. Fedotov; O. A. Kolevatova; A. M. Zheltikov; Paolo Marsili; A. Ruffini; F. Giammanco
The processes of third-harmonic and difference-frequency generation through the four-wave mixing of picosecond pulses in gas-filled hollow fibers are experimentally studied. Due to the improvement of phase-matching conditions with an appropriate choice of the gas pressure and optimal parameters of the hollow fiber, we were able to use hollow fibers with a large length (up to 30 cm) for difference-frequency generation, which resulted in a considerable increase in the power of the difference-frequency signal at the output of the fiber. Our experimental data reveal a considerable influence of high-order waveguide modes on four-wave mixing processes in a hollow fiber. It is shown that the waveguide regime of nonlinear optical interactions implemented in hollow fibers removes the limitations on the efficiency of third-harmonic and sum-frequency generation, which are characteristic of the tight-focusing regime in media with normal dispersion and which are due to the geometric phase shift arising in tightly focused light beams.
Laser Optics 2003: Solid State Lasers and Nonlinear Frequency Conversion | 2004
Nicolo' Beverini; Giorgio Carelli; A. De Michele; A. Moretti; B. Nyushkov; A. Ruffini
An heterodyne technique employing ultra-wide band Schottky diodes and a femtosecond pulsed laser was tested to perform frequency measurements in the far infrared range. Preliminary experiments demonstrate an efficient frequency down-conversion in Schottky diodes by mixing the microwave radiation with the output of a femtosecond laser used as a reference local oscillator.
conference on lasers and electro optics | 2001
A. B. Fedotov; A. N. Naumov; D. A. Sidorov-Biryukov; O. A. Kolevatova; A. M. Zheltikov; F. Giammanco; Paolo Marsili; A. Ruffini
Applied Physics B | 2001
Nicolo' Beverini; Enrico Maccioni; Paolo Marsili; A. Ruffini; F Sorrentino
Quantum Electronics | 2004
Nicolo' Beverini; M. Prevedelli; F. Sorrentino; B Nyushkov; A. Ruffini
Laser Physics | 2001
A. B. Fedotov; F. Giammanco; A. N. Naumov; Paolo Marsili; A. Ruffini; O. A. Kolevatova; D. A. Sidorov-Biryukov; A. M. Zheltikov
6th symposium on Frequency Standards and Metrology, | 2002
Nicolo' Beverini; Enrico Maccioni; A. Ruffini; F. Sorrentino; V. Baraulia
International Conference on Lasers '99 | 2000
A. Bertolini; Nicolo' Beverini; Giorgio Carelli; N. Ioli; Enrico Maccioni; C. A. Massa; A. Moretti; A. Ruffini; O. Tommasi; F. Strumia
EFTF 2000 (14th Eur. Frequency and Time Forum) | 2000
Nicolo' Beverini; Enrico Maccioni; Paolo Marsili; A. Ruffini; F. Sorrentino
