Interaction of collinear light beams with different wavelengths in a heterogeneous liquid-phase nanocomposite

Optical Nonlinearity of Dielectric Nanocomposite

“…Over the last years, experimental studies of nonlinear optical properties of nanocomposites [1][2][3][4][5][6][7][8] with small concentrations of wide band semiconductor and dielectric nanoparticles embedded into dielectric matrix have revealed, that these media, influenced by either of nanosecond pulses and continuous illumination of near infrared and visible light, demonstrate a low threshold (pulse regime thr P < 0.5 2 nJ cm ) response. This response disappears when the light intensity becomes high, and the dependence of intensity of the output light (passed through the nanocomposite) on the input light (incident upon the nanocomposite) intensity ( ) out in P P becomes a linear one.…”

“…The character of this response in these media was tightly bound with a refraction index and an energy gap width of nanoparticles material. The results of the work [7][8][9][10] show that the same effects in such media can be witnessed in case of use of continuous laser radiation as well. In both cases modulation of optical properties of liquid heterogeneous medium can be caused by a combination of the next processes: light-induced absorption change, light scattering by nanoparticles, thermal and photoinduced modulation of refraction index.…”

“…It was concerned, presumably, with the considerations that such energy-gap width could cause the nonlinear optical response of the medium in the ultraviolet range of light. However, recent studies [7,8] have shown that HLPN based upon dielectric nanoparticles can feature low-threshold nonlinear optical response to an external illumination, impulse and continuous alike, in the near infrared or visible ranges of light.…”

“…Thirdly, electric dipole moments of transitions within such quasizero dimensional objects can be higher than such moments of volume samples [9,10,[15][16][17][18][19][20][21][22]. As it was shown during the experimental studies [8,9], a substantial factor which determines nonlinear optical properties of HLPN is a character of dependence of liquid matrix refraction index on the temperature of the matrix medium.…”

“…Thus this paper, being based upon the results of our works [1][2][3][7][8][9][10], deals with experimental and theoretical studies of physical characteristics of nanoparticles responsible for specific optical properties of dielectric nanocomposites. During theoretical description and explanation of experimental data obtained, we considered nanoparticle as a multi-particle quantum system of charges which combines elements of quantum structures of a polyatomic molecule and a bulk crystal.…”