Frequency and temperature dependence of the TO phonon-polariton decay in GaP

Abstract

The temperature and frequency dependence of the decay time of the transverse optical ͑TO͒ phonon polariton in GaP has been measured by impulsive stimulated Raman scattering with 25-fs optical pulses. Tuning of the polariton frequency from 365 to 361 cm Ϫ1 reveals drastic changes of the polariton decay time with temperature. This result is explainable by third-order anharmonic decay of polaritons into two acoustic phonons taking into account the temperature-dependent shift of the van Hove singularity in the two-phonon density of states of the acoustic phonons at the edge of the Brillouin zone. The frequency dependence of the TO phonon-polariton decay times measured at different temperatures allows one to directly observe the shift of this singularity with temperature.

Magnon squeezing in antiferromagneticMnF2andFeF2

“…Since then, squeezed states have also been realized in other systems. In the past decade, squeezed states of vibrational degrees of freedom have been experimentally demonstrated for molecules 6 and solids, [7][8][9][10] and, more recently, squeezed atomic spin states have also been achieved. [11][12][13][14][15] Because spin squeezing is closely related to quantum entanglement, squeezed states hold promise for applications in quantum computing.…”

“…Impulsive stimulated second-order inelastic light scattering has been shown previously to be a practical means of generating squeezed states for phonons in solids. [7][8][9][10]20 Second-order Raman coupling between the incident light and lattice vibrations is proportional to the square of the phonon amplitude. The light-induced interaction between a pair of phonons gives rise to squeezing because it results in a change in the frequency of the harmonic oscillator for the duration of the incident light pulse and, as such, it is a parametric perturbation.…”

Bulk and surface phonon–polaritons in ternary mixed crystals

“…Later, the surface phonon-polaritons in the GaAs film, as well as GaP thin slab and other materials were also observed [9][10][11]. Moreover, the generation, dispersion and decay of phonon-polaritons have been extensively investigated experimentally by various optical methods [12][13][14][15][16]. Very recently, the promising technique of terahertz (THz) timedomain spectroscopy has been used to observe phonon-polariton dispersion relations [17].…”

“…The phonon-polariton results in the infrared absorption and dielectric abnormality, etc, and concerns the developments and applications of new photoelectron devices [14][15][16][17][18][19][26][27][28]. Employing polar TMCs in artificial materials can enable one to modify the vibrational and optical properties as well as the polariton characteristics of the systems in a controlled manner, and may extend their applications to devices [20][21][22][23][24].…”