Masahiro Kitajima

Coherent optical phonons in diamond

The authors report femtosecond dynamics of the coherent optical phonon of single crystal diamond. Sub-10fs, 395nm laser pulses excite 40THz coherent phonons with an extremely small damping rate (0.15ps−1). Linear power dependence of the phonon amplitude under off-resonant excitation condition gives a direct evidence for an eletric-field-driven generation mechanism. The coherent phonon generation is noticeably suppressed by doping with nitrogen impurities, in spite of their absorption in the near ultraviolet. The present study demonstrates that a simple pump-probe technique can be a powerful tool for evaluating the ultrafast coherent electronic and lattice dynamics of diamond materials.

Ultrafast dynamics of coherent optical phonons and nonequilibrium electrons in transition metals

The femtosecond optical pump-probe technique was used to study dynamics of photoexcited electrons and coherent optical phonons in transition metals Zn and Cd as a function of temperature and excitation level. The optical response in time domain is well fitted by linear combination of a damped harmonic oscillation because of excitation of coherent

Forcibly driven coherent soft phonons in GeTe with intense THz-rate pump fields

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Fully symmetric and doubly degenerate coherent phonons in semimetals at low temperature and high excitation : similarities and differences

phonon and a subpicosecond transient response due to electron-phonon thermalization. The electron-phonon thermalization time monotonically increases with temperature, consistent with the thermomodulation scenario, where at high temperatures the system can be well explained by the two-temperature model, while below

Power- and Polarization-Dependences of Coherent Phonons of Tetrahedrally Bonded Semiconductors

ensuremath{approx}50phantom{rule{0.3em}{0ex}}mathrm{K}

Phonon autoecho in bismuth and antimony single crystals

the nonthermal electron model needs to be applied. As the lattice temperature increases, the damping of the coherent

Fano interference with the alternating asymmetry parameter in time-domain experiments

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Optical Imaging of Defect Density Distribution in Ion-Implanted GaAs using Ultrafast Carrier Dynamics

phonon increases, while the amplitudes of both fast electronic response and the coherent

On the nature of coherent phonons generated by ultrashort laser pulses in single-crystal antimony

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Spectrally filtered time domain study of coherent phonons in semimetals

phonon decrease. The temperature dependence of the damping of the