Search

The paper investigates the cross-section and probability of absorption of ultrashort electromagnetic pulses by ITO nanoparticles in a dielectric matrix. It discusses the suitability of using the total probability of photoabsorption instead of the probability per unit time for such pulses. It is shown that in the case of negative detuning of the pulse carrier frequency from the plasmon resonance frequency, the photoabsorption probability is a nonlinear function of the pulse duration. For detuning with sufficiently large magnitude, the formation of a maximum is possible in this functional relationship, the position of which depends on the refractive index of the matrix. A method is proposed for measurement of environmental parameters by the analysis of time dependence of this photoprocess. Calculations are performed for a corrected Gaussian pulse and ITO nanoparticles with different doping levels.

The frequency dependence of the cross section of photon absorption by semiconductor nanoparticles in the infrared range is considered. Light is absorbed by conduction electrons with plasmon formation and electrons in the traps both within the bulk and on the nanoparticle surface. The regularities of the photoabsorption cross section largely depend on the size of the nanoparticles. For sufficiently large nanoparticles, there appear only two characteristic peaks in the cross section distribution corresponding to light absorption by two types of electrons—conduction electrons and electrons in the volume traps of nanoparticles. The number of electrons trapped on the surface is relatively small, and the electrons do not contribute to the total cross section of photoabsorption. In the case of photon absorption by quantum dots, the contribution of these surface electrons as well as a third peak is evident. This result occurs due to a complex dependence of the number of electrons in the traps on their depth and s...