共查询到20条相似文献,搜索用时 15 毫秒
1.
We present a quantum electrodynamic theory which shows for the first time how stimulated Raman scattering builds up, both spatially and temporally, from spontaneous Raman scattering. We analytically solve operator Maxwell-Bloch equations to find the Stokes field operator, and thus the Stokes intensity, for both monochromatic and broad-band (phase diffusion) pump lasers. 相似文献
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The nitrogen laser pumped dye laser output has been studied with emphasis on the behaviour of amplified spontaneous emission
(ASE) with respect to the tuning wavelength, pump energy, dyes and their concentration and solvents. Spectral spread of ASE
is narrower than fluorescence and its maximum is shifted towards the red side. However, lasing occurs beyond the ASE region.
ASE is small at high gain wavelength and increases at the edges of the gain curve. Laser energy is highest at the ASE peak
with minimum ASE present in the output. ASE is reduced with increased laser energy in the energy transfer dye lasers. 相似文献
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Dye amplifiers are studied theoretically in the presence of amplified spontaneous emission (A.S.E.). The set of coupled rate equations is solved analytically in the steady state regime. Analytical relations are derived which express the spectral and spatial dependence of A.S.E. From the spatial dependence of A.S.E., the spatial dependence of the excited state population is obtained. A case of practical interest is treated: that of a rhodamine 6G amplifier transversely excited by a neo-dymium laser. 相似文献
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Y.H. Meyer 《Optics Communications》1978,26(2):261-264
Intracavity stimulated Raman scattering gain is used to force spectral condensation of the dye laser emission to ~ 2 Å wide lines in an untuned dye oscillator longitudinally pumped by a repetitive N2-laser. Several stimulated Stokes Raman frequencies of the solvents are observed. Interpretation is discussed in terms of spectro-temporal evolution of the dye intensity within an homogeneous band oscillator. 相似文献
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The utilization of a simple focused optical cell to bring to light the competition between wideband stimulated Brillouin scattering (WSBS) and forward stimulated Raman scattering (FSRS) is investigated experimentally. A pulsed, wide bandwidth second-harmonic Nd:YAG laser is used as the pump source. We found that, the competition between WSBS and FSRS is an alternate process, which one dominated depends on the linewidth and energy of the pump laser, focal length, and optical breakdown. 相似文献
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Steady state transmission measurements are made in flashpumped attenuating or amplifying solutions of fluorescein, 2, 7 dichlorofluorescein and rhodamine 6G in aerated ethanol. Stimulated emission and transient absorption are studied by varying the input signal intensity. It is shown that the presence of stimulated emission can be demonstrated in attenuating solutions also. Results are interpreted with the aid of the steady-state gain theory. 相似文献
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Different dyes in locally separated cells have been investigated in order to obtain information about the mechanisms responsible for the generation of stimulated resonance Raman scattering. The experiments show in agreement with the theoretical results that the appearance of initial signals as well as the effect of dye amplification influences the behaviour of stimulated resonance Raman scattering. 相似文献
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ZhiWei Men XiuPing Sun WenHui Fang ZuoWei Li Biao Cao ShuQin Gao GuoHui Lu 《中国科学G辑(英文版)》2009,52(4):529-533
β-carotene with double fluorescence characteristics and large third-order optical nonlinearities, which is dissolved in the
carbon disulfide (CS2) as the core medium of a liquid core optical fiber (LCOF), is applied in the study of the CS2 stimulated Raman scattering (SRS). The results of this study show that when the concentrations of solution are more than
3.72×10−7 mol/L, the amplified spontaneous emission (ASE) of β-carotene is the main factor influencing the threshold and intensity
of Stokes lines; when the concentrations of solution are lower than 3.72×10−7 mol/L, the ASE disappears and the fluorescence plays the key role: The high-order Stokes lines may be observed at very low
input-laser power, and the Stokes thresholds decrease as the solution concentration increases. The result may be widely used
in the study of broadband stimulated radiation laser and seeding laser.
Supported by the National Natural Science Foundation of China (Grant No. 10774057) 相似文献
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Strong multi-order forward stimulated Brillouin scattering (SBS) has been observed in the backward pumped S-band distributed fiber Raman amplifier (FRA) with tunable narrow signal source (less than 100 MHz) when the pump power of FRA reached the SBS threshold. This does not obey the theory that only weak backward SBS lines exist according to the conservation of energy and momentum and the wave vector selected rule. This is because the sound waveguide characteristic weakens the wave vector rule, and the forward transmitted sound waveguide Brillouin scattering lines are generated and amplified in FRA.When the pump power is further increased, 11 orders of SBS lines and comb-like profile are observed. For the excited line, the frequency is 197.2296 THz and the power is 0 dBm. The even order SBS lines are stronger than odd order SBS lines, the power of the 2nd and 4th order SBS lines is 1.75 dBm, which is 16 dB higher than that of the 1st and 3rd order SBS lines. The odd order SBS lines are named BrillouinRayleigh scattering lines. 相似文献
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Simultaneous forward and backward stimulated Raman scattering (SRS) in methane pumped by a single longitudinal mode Nd:YAG
laser at 355 nm has been investigated both experimentally and numerically. For forward SRS, a maximum energy-conversion efficiency
of 55% was obtained under 24 atm, while for backward SRS the corresponding figure was 58% under 4.7 atm. Under low pressures
or at low pump energies, the conversion efficiency for backward SRS was found to be much higher than that for forward SRS,
while the situation is quite the contrary under high pressures and at high pump energies. A quasi-two-dimensional numerical
model is introduced to elucidate the competition between forward and backward SRS; we conclude that the high-pressure and
high-pump-energy experimental results should be caused by the thermal defocusing effect in the SRS process. This is confirmed
by the experimental fact that a decrease of the pulse-repetition rate increases the conversion efficiency for backward SRS
but decreases that for forward SRS under high pressures. Our calculated results are in good agreement with the experimental
results at a pulse-repetition rate of 2 Hz.
PACS 42.55.Ye; 42.65.Dr; 42.65.Es 相似文献
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M. Olivík 《Czechoslovak Journal of Physics》1992,42(1):93-102
Coherent state technique and maximal Lyapunov exponent method are used for the study of deterministic chaos in a system governing stimulated Raman scattering. The influence of the external pumping on dynamics of the system is investigated. Phase portraits and FFT spectra are presented.The author would like to express his sincere thanks to prof. J. Peina for his comments and stimulating discussions. 相似文献
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We have found a simple analytical expression which describes the relation between amplified spontaneous emission (ASE) and small-signal gain in short-pulse amplifiers. It is also shown that the contrast of the short pulse to the ASE is weakly dependent on the saturation of the ASE, and influenced mainly by the saturation of the short pulse. The theoretical considerations were verified by measurements. 相似文献
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Menyuk CR 《Physical review letters》1989,62(25):2937-2940