Spin-lattice coupling is one of the most prominent interactions mediating response of spin ensemble to ultrafast optical excitation. Here we exploit optically generated coherent and incoherent phonons to drive coherent spin dynamics, i.e. precession, in thin films of magnetostrictive metal Galfenol. We demonstrate unambiguously that coherent phonons, also seen as dynamical strain generated due to picosecond lattice temperature raise, give raise to magnetic anisotropy changes of the optically excited magnetic _lm; and this contribution may be comparable to or even dominate over the contribution from the temperature increase itself, considered as incoherent phonons.
We use the internal picosecond strain pulses to control the electron energy in a semiconductor quantum well. For
generating the strain pulse a 100 nm thick metal transducer was hit by intense laser pulse and a strain pulse with duration
~10 ps and amplitude up to 0.1% was injected into a GaAs substrate. This strain pulse travels strongly directed through
the crystal towards the quantum well generating at each momentary position a "nano-earthquake". When the quantum
well is hit by this "earth quake", the exciton resonance is shifted on a value up to 10 meV on a ps time scale.
Three-dimensional opal-VO<sub>2</sub> photonic crystals were synthesized by the chemical bath deposition technique. The Bragg reflection spectra from the (111) planes of the crystals were measured as a function of the temperature in the range between 15 and 100°C. The thermal hysteresis loop of the reflection peak position due to the phase transition in VO<sub>2</sub> filling the opal voids was observed. A theoretical model of the periodic layered medium was proposed to describe quantitatively the reflection spectra of opal-like structures. The values of the dielectric constants of the VO<sub>2</sub> below and above the phase transition temperature have been estimated which give the best fit within the model considered.
The water vapor absorption spectra between 11,600 and 12,750 cm<SUP>-1</SUP> have been recorded with the Fourier-transform spectrometer (Kitt-Peak, Az) at the resolution of 0.012 cm<SUP>-1</SUP> and with the path length of 434 m. Three spectra were used for the analysis: two spectra of water vapor recorded with the Kitt Peak interferometer at the pressure of 1.5 and 17 Torr and the spectrum published by Toth. The experimental details and data reduction procedure have already been discussed, the line assignments were performed simultaneously with calculation of the line positions and intensities that allowed one to obtain an accurate set of experimental rotational energy levels for the eight interacting vibrational states. (131), (211), (013), (230), (112), (032), (051) and (310).
High resolution intracavity laser spectrometers were developed in 8000 - 11000 cm<SUP>-1</SUP> spectral region. Threshold sensitivity of the spectrometers (10<SUP>-7</SUP> - 10<SUP>-8</SUP> cm<SUP>-1</SUP>) allows one to carry out effective investigation of high vibrational-rotational water vapor states at low and high temperatures. Vibrational states of H<SUB>2</SUB><SUP>16</SUP>O, H<SUB>2</SUB><SUP>18</SUP>O, D<SUB>2</SUB>O and HDO were investigated in a spectral region up to 11000 cm<SUP>-1</SUP>. Spectroscopic parameters were determined and vibrational parameters were used for calculation of the vibrational energy levels up to 16000 cm<SUP>-1</SUP>. New types of resonances between states of different polyads have been found.