Optically excited near-surface phonons of TiO(2) (110) observed by fourth-order coherent Raman spectroscopy.
نویسندگان
چکیده
We observed the fourth-order and third-order optical responses in the time domain on a TiO(2) (110) surface covered with trimethyl acetates. Coherent vibrations assignable to near-surface phonon modes were present at 179, 191, 359, 440, 507, 609, and 823 cm(-1) in the fourth-order responses. The amplitude and phase of each mode were determined with different azimuths and polarizations of pump and probe light pulses. Vibrational assignments and possible mechanisms to excite the vibrations were discussed.
منابع مشابه
Observation of coherent zone-folded acoustic phonons generated by Raman scattering in a superlattice
We have used pulse time-of-flight techniques to examine the phonon emission from an optically excited GaAs/AlAs superlattice structure. For laser excitation wavelengths shorter than 767 nm ~the energy of E1HH1 transition!, we detect a significant longitudinal acoustic phonon component directed in a narrow beam normal to the structure. Under identical excitation conditions, generation of coheren...
متن کاملUltrafast evolution of the excited-state potential energy surface of TiO2 single crystals induced by carrier cooling.
We investigate the influence of carrier cooling dynamics in TiO(2) on the excited-state potential energy surface along the A(1g) optical phonon coordinate after above band-gap excitation using ultrashort ultraviolet pulses. The large amplitude coherent oscillation observed in a pump-probe transient reflectivity measurement shows a phase shift of -0.2π with respect to a purely instantaneous disp...
متن کاملEmission of Submillimeter Electromagnetic Waves by Coherent Phonons.
We report on the first observation of the emission of electromagnetic radiation from coherent lattice vibrations in a semiconductor. Coherent optical phonons are excited by ultrashort laser pulses in singlecrystal tellurium. THz frequency radiation emitted by the Dember-field-driven phonons is detected by time-resolved THz-emission spectroscopy. The measurements are complemented by optical pump...
متن کاملUltrafast Optical Excitation of a Combined Coherent-Squeezed Phonon field in SrTiO3.
We have simultaneously excited a coherent and a squeezed phonon field in SrTiO3 using femtosecond laser pulses and stimulated Raman scattering. The frequency of the coherent state (a 1.3 THz) is that of the A1g-component of the soft mode responsible for the cubic-tetragonal phase transformation at approximately 110 K. The squeezed field involves a continuum of transverse acoustic phonons domina...
متن کاملQuantifying electron-phonon coupling in CdTe12xSex nanocrystals via coherent phonon manipulation
We employ ultrafast transient absorption spectroscopy with temporal pulse shaping to manipulate coherent phonon excitation and quantify the strength of electron-phonon coupling in CdTe1 xSex nanocrystals (NCs). Raman active CdSe and CdTe longitudinal optical phonon (LO) modes are excited and probed in the time domain. By temporally controlling pump pulse pairs to coherently excite and cancel co...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The Journal of chemical physics
دوره 131 8 شماره
صفحات -
تاریخ انتشار 2009