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151.
A laser system comprising a synchronously pumped picosecond dye laser with combined cavity-distributed feedback and a two-stage
dye amplifier is described. The dependence of the laser pulse duration on the detuning of the cavity length, the pumping level
of the active medium, and the pulse number in the pulse train was investigated. It is shown that the combination of the two
types of feedback provides more than ten-fold shortening of the dye laser ultrashort pulse duration.
B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 47–55, January–February, 1998. 相似文献
152.
Local probing of second-order susceptibilities with a near-field optical microscope is demonstrated for the first time. Using an uncoated fiber tip as a light source, near-field images of a surface of y-cut LiNbO3 crystal and of a multilayer Langmuir–Blodgett film of 2-docosylamino-5-nitropyridine are obtained at the fundamental pump and second harmonic wavelengths while simultaneously recording surface topography. It is shown that optical second-harmonic images for different polarizations of the pump light reflect the difference in magnitude of the corresponding components of the second-order susceptibility tensor. Various degrees of correlation in contrast of optical (fundamental and second harmonic) and topographical images are observed and discussed. 相似文献
153.
154.
To whom correspondence should be addressd. 相似文献
155.
S. Chakrabarti B. Ray P. N. Ghosh 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(3):359-368
The effects of a strong control or pump laser, counter propagating
or copropagating with the probe beam, on the probe absorption spectra of
85Rb and 87Rb-D2 transitions have been investigated inside
a room temperature Rb vapour cell. In both cases a set of strong velocity
selective resonance dips are observed at different velocities. Their
movements across the Doppler broadened probe absorption profile have been
studied for different lock frequencies of the control laser. These spectra
are modified by optical pumping effects due to the presence of another
hyperfine component of the ground state. A repumping laser, from the dark
hyperfine component of the ground level transfers almost 75% of the atoms
from the dark state to the pump probe cycle hence reducing the optical
pumping effect. A numerical simulation is done to explain the observed
spectra. The effect of a control laser on the Lamb dip spectrum of the probe
laser has also been investigated. The control beam is used to improve the
strength of a weak hyperfine dip on the Doppler broadened probe spectrum.
The strength of the hyperfine dip increases by a factor of 3.2 in presence
of the control laser. The observed dips show that pump-probe spectroscopy
can be used as velocity selectors of atoms. 相似文献
156.
L. C. Wang X. L. Huang X. X. Yi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(2):345-349
The Landau-Zener (LZ) transition of a two-level system
coupling to spin chains near their critical points is studied in
this paper. Two kinds of spin chains, the Ising spin chain and XY
spin chain, are considered. We calculate and analyze the effects of
system-chain coupling on the LZ transition. A relation between the
LZ transition and the critical points of the spin chain is
established. These results suggest that LZ transitions may serve as
the witnesses of criticality of the spin chain. This may provide a
new way to study quantum phase transitions as well as LZ transitions. 相似文献
157.
Jean-François Bisson Akira Shirakawa Youhei Sato Yuri Senatsky Ken-Ichi Ueda 《Optical Review》2004,11(6):353-357
A Nd:YAG rod active element placed inside a resonator was pumped by the second harmonic radiation (the wavelength =0.532 m) of a Q-switched Nd:YAG laser diffracted at a circular aperture. Various distributions of pumping intensity in the Fresnel (near-field) region along the direction of the pump beam diffraction were produced. Inversion profiles with maxima or minima at the resonator axis were formed in the active element, depending on its distance from the circular aperture. Gain-switched operation of the Nd:YAG rod laser at =1.064 m is reported at the fundamental mode and also at the TEM01, TEM01* and other higher-order modes for different positions of the active element in the near-field region. Applications of such diffractive optical pumping for the concentration of the pumping radiation into the active media and for laser beam profling are discussed. © 2004 The Optical Society of Japan 相似文献
158.
A. V. Akimov A. V. Sokolov N. N. Kolachevsky A. N. Matveev V. N. Sorokin S. I. Kanorsky 《Journal of Russian Laser Research》2003,24(2):129-142
Dark resonances in the 154Sm -system 4f
66s
2(7
F
0) 4f
66s6p(9
F
1
0) 4f
6
s
2(7
F
1) are observed alongside the velocity selective optical pumping. The shape of the resulting spectra strongly depended on the buffer gas (He, Ar) pressure due to velocity-changing collisions (VCC): the sign of the effect could be reversed from the dark to the bright resonance. The observed spectra are interpreted within the framework of the hard-sphere collision model. The role of VCC in the formation of the dark state in the -system is discussed. 相似文献
159.
Xiao Huang Yanxiang Bao Xizhang Luo Xiaorong Zou 《International Journal of Infrared and Millimeter Waves》2002,23(7):1013-1018
A CO2 infrared laser system with a etalon to be the longitudinal mode select equipment was set up to be the optically pump source, as well as a mini NH3 with 20cm long sample tube to be the sub-millimeter wave laser. CO2-9R(16) line was chose to pump the mini-NH3 SMMW laser, and 90.4um SMMW line was obtained by single-longtudinal-mode or two-longitudinal-mode pumping. Experimental comparison of output power and operating gas pressure between single and two-longitudinal-mode OPSMMWL were studied. It was found that the two-longitudinal-mode OPSMMWL could get higher output power and broader spectrum, existed a lower operating gas pressure and wider range of operating gas pressure. These experimental results verified the theoretical calculations before. 相似文献
160.
M. I. Dzyubenko V. V. Maslov V. P. Pelipenko V. V. Shevchenko E. A. Kupko 《Journal of Applied Spectroscopy》2004,71(3):435-440
The spectral and lasing characteristics of a number of dyes for the red and near IR portions of the lasing spectrum in laser and lamp pumpings are investigated. Smooth tuning of a pulse-periodic lamp-pumped laser in the 660–720 nm range and generation of its second harmonic in the 330–360 nm region were obtained. As a result, the radiation range of the earlier developed tunable laser source has been extended in the red and near UV regions of the spectrum. The use of mixtures of dyes and proton-donating additives in working solutions has substantially improved the energy characteristics of this source. 相似文献