1,723,372 research outputs found
Petrov V. V. — La population de l'Inde. Esquisse démographique
No full textG. G. Petrov V. V. — La population de l'Inde. Esquisse démographique. In: Population, 21ᵉ année, n°3, 1966. pp. 583-584
Petrov V. V. — La population de l'Inde. Esquisse démographique
No full textG. G. Petrov V. V. — La population de l'Inde. Esquisse démographique. In: Population, 21ᵉ année, n°3, 1966. pp. 583-584
Generation of the fourth harmonic of a femtosecond Ti : sapphire laser
No full textA high-repetition-rate femtosecond laser system operating, for the first time to our knowledge, in the spectral region near 200 nn is described. Frequency quadrupling of a mode-locked Ti:sapphire laser results in maximum average powers of 6 mm (165-fs pulses) and 15 mW (340-fs pulses) at 82 MHz. The shortest wavelength achieved is 193.7 nm. (C) 1998 Optical Society of America OCIS codes: 190.2620, 190.7110, 320.7080, 320.111
Mid-infrared femtosecond optical parametric generator pumped by a Cr : forsterite regenerative amplifier at 1.25 mu m
No full textWe demonstrate a novel traveling-wave type optical parametric generator based on 1.25 mu m pumping of AgGaS2 that produces tunable, high-power and almost transform-limited 200-fs pulses in the mid-infrared up to 8 mu
Application of the solid solution CdxHg1-xGa2S4 as a nonlinear optical crystal
No full textWe review the optical properties of the mixed crystal CdxHg1-xGa2S4, propose three potential applications to which various physical properties can be tailored, and present experimental results of femtosecond optical parametric amplification in the mid IR from 5.5 to 8 mum with 1.25-mum pumping by a 1-kHz Cr:forsterite regenerative amplifier. (C) 2002 Optical Society of Americ
Femtosecond noncollinear optical parametric amplification in the mid-infrared range with 1.25 mu m pumping
No full textWe study noncollinear three-wave interaction in a traveling wave optical parametric amplifier operating in the mid-infrared spectral range between 6 and 8 mum using HgGa2S4 and AgGaS2 as nonlinear optical crystals. Calculations reveal that matching of the group velocities in both crystals is possible in a wider spectral (or angular) region for type-I interaction. High-power femtosecond pulses at 1.25 mum from a Cr:forsterite regenerative amplifier are used for pumping the optical parametric amplifier at a repetition rate of 1 kHz. Experimentally we verify the advantages of noncollinear interaction by increasing the conversion efficiency approximately sixfold in the saturation regime as compared to the collinear case. The maximum idler energy measured near 6 mum exceeds 4 muJ and typical pulse durations are about 300 f
Mercury thiogallate mid-infrared femtosecond optical parametric generator pumped at 1.25 mu m by a Cr : forsterite regenerative amplifier
No full textWe demonstrate a novel traveling-wave-type optical parametric generator based on 1.25-mu m pumping of HgGa2S4 that produces tunable, high-power, transform-limited proportional to 200-fs pulses in the mid-IR from 5 to 9 mu m. Output idler energies on the microjoule level are obtained with maximum conversion efficiency of 11% for the amplifier stage, which is more than two times better than the results obtained with an analogous sample of the widely spread material AgGaS2. (C) 2000 Optical Society of Americ
Femtosecond noncollinear parametric amplification in the mid-infrared
No full textWe demonstrate the potential of noncollinear parametric interaction in a traveling wave MgO:LiNbO3 optical parametric amplifier operating in the mid infrared near 3 mu m. Our calculations indicate that for pump wavelengths below 816 nm (the wavelength near which collinear group matching is achieved at a fixed signal wavelength of 1064 nm), the group velocity mismatch can be reduced and the parametric gain can be increased by noncollinear propagation of the three beams. Experimentally we verify this by producing approximate to 2.5 times higher energy and shorter pulse duration (125 fs against 180 fs) at the idler wavelength by noncollinear interaction as compared to collinear interaction. (C) 1999 Elsevier Science B.V. All rights reserve
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