Self-phase modulation in a thin fused silica plate upon interaction with a converging beam of down-chirped femtosecond radiation

• Published in: Quantum electronics (Woodbury, N.Y.) N.Y.), 2015-01, Vol.45 (5), p.415-420
• Main Authors: Grudtsyn, Ya.V., Zubarev, I.G., Koribut, A.V., Kuchik, I.E., Mamaev, S.B., Mikheev, L.D., Semjonov, S.L., Stepanov, S.G., Trofimov, V.A., Yalovoi, V.I.
• Format: Article
• Language: English
• Subjects: BEAMS; Beams (radiation); CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; down-chirped femtosecond pulse; EXPERIMENTAL DATA; Femtosecond pulses; Focal plane; FOCUSING; four-wave mixing; Fused silica; LINE BROADENING; Mathematical models; MIRRORS; MODULATION; NONLINEAR PROBLEMS; Nonlinearity; NUMERICAL SOLUTION; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; PLASMA; PULSES; SCHROEDINGER EQUATION; self-compression; self-phase modulation; SILICA; SPECTRA
• ISSN: 1063-7818; 1468-4799
• DOI: 10.1070/QE2015v045n05ABEH015766

The mechanism of spectral broadening and self-compression of down-chirped femtosecond pulses in the visible range upon nonlinear interaction of a converging Gaussian beam with a fused silica plate is experimentally and theoretically investigated. It is found experimentally that when the intensity increases and plasma is formed in the sample, the regime of femtosecond pulse splitting is transformed into the single-pulse generation regime during nonlinear interaction. As a result of self-compression, the duration of the initial transform-limited pulse is reduced by a factor of 3. Based on the numerical solution of the generalised nonlinear Schrödinger equation, with the plasma formation disregarded, it is shown that the profile, spectrum and temporal phase of the pulse transmitted through the sample acquire a stationary shape behind the focal plane of the focusing mirror. The calculation results are in good agreement with experimental data. The possibility of parametric amplification of the pulse spectral components under given experimental conditions is discussed.