Stimulated Rayleigh–Mie scattering (SRMS) in two-photon absorption liquids is realized by a Fourier transform-limited pulsed Nd-glass laser. For the first time, we have measured anti-Stokes spectral shifts of SRMS in toluene and hexane colloids of Ag nanoparticles, as well as in pure toluene. The suspensions are prepared in the plasma discharge excited in a liquid exposed to an intense ultrasonic field above the cavitation threshold. This novel technique has been developed for the synthesis of various nano-sized materials; it provides silver nanoparticles suspensions with controlled narrow distribution of the particle size. Ultrasonic cavitation results in a drastic change in the physical properties of the liquid, providing specific conditions in the electrical discharge plasma. Ag nanoparticles with 1-2 nm radii in toluene and hexane are obtained from silver electrodes under these specific conditions and acquire unique surface characteristics which prevent them from secondary agglomeration. The values of anti-Stokes spectral shifts of SRMS appreciably exceed the Rayleigh line width in those liquids. The four-wave mixing method is applied both experimentally and theoretically to display the process as Rayleigh-induced parametric generation. We show that the amplification effect is provided predominantly by thermally induced coherent polarization oscillations, while an interference-assisted thermal grating provides formation of a self-induced optical cavity inside the interaction region.
The efficiency of a real heat engines is considered. Basing on the entropy production minimum principle it is shown that
the maximum efficiency of such a machine with an optimum power is n= 1-√T2/T1 defined by the root dependence of cooler and heater temperatures. This disappointing result was obtained earlier for the
optimizing the power of Carnot cycle. In this paper we derive aforementioned expression from more general conditions.
And we show that it is could be applicable to describe global changes in living and nonliving nature.
The spectral characters and increments of stimulated Rayleigh scattering in pure liquids and suspensions of Ag nanoparticles in toluene and hexane of principally different nature were investigated in this work. The correlation of two photon absorption spectra and stimulated scattering efficiency were discovered and analyzed. It is shown experimentally that the frequency shift of the scattered signal relative to the pump frequency greatly exceeds the theoretical value.
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