Direct time-resolved measurement of anharmonic lattice vibrations in ferroelectric crystals

Brennan, Ciaran J.; Nelson, Keith A.

doi:10.1063/1.475293

Cited by 46 publications

(32 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Molecular or ionic motions in the THz frequency range are a promising target for coherent control since they are in certain systems directly connected to macroscopic properties such as ferroelectricity or ferroelasticity. Large-amplitude THz motion can be excited by optical ultrashort pulse through the impulsive stimulated Raman scattering process and controlled access to the anharmonic regime of the lattice potential along the soft mode has been demonstrated [128]. However, excitation with optical pulses is limited to Raman active modes and the high excitation fluencies necessary in these experiments can lead to damage in opaque samples.…”

Section: Vibrational Excitationmentioning

confidence: 99%

Intense ultrashort terahertz pulses: generation and applications

Hoffmann¹,

Fülöp²

2011

J. Phys. D: Appl. Phys.

333

215

View full text Add to dashboard Cite

Ultrashort terahertz pulses derived from femtosecond table-top sources have become a valuable tool for time-resolved spectroscopy during the last two decades. Until recently, the pulse energies and field strengths of these pulses have been generally too low to allow for the use as pump pulses or the study of nonlinear effects in the terahertz range. In this review article we will describe methods of generation of intense single cycle terahertz pulses with emphasis on optical rectification using the tilted-pulse-front pumping technique. We will also discuss some applications of these intense pulses in the emerging field of nonlinear terahertz spectroscopy.

show abstract

Section: Vibrational Excitationmentioning

confidence: 99%

Intense ultrashort terahertz pulses: generation and applications

Hoffmann¹,

Fülöp²

2011

J. Phys. D: Appl. Phys.

333

215

View full text Add to dashboard Cite

show abstract

“…5,6 Phase control over degenerate phonon modes has also been achieved recently. 7 Here, we present the first demonstration of coherent control over acoustic phonons in semiconductor superlattices, which, in principle, allows to selectively excite any branch in the phonon dispersion, while suppressing other branches.In the lower frequency range acoustic phonons exhibit a linear dispersion relation ϭv sound q, where v sound is the sound velocity of the material and q the wave vector of the phonon. In artificial superlattices, the acoustic phonon spectrum exhibits zone-folding within the mini-Brillouinzone due to the new periodicity along the growth direction.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Coherent control of acoustic phonons in semiconductor superlattices

Bartels

Dekorsy

Kurz

et al. 1998

Applied Physics Letters

View full text Add to dashboard Cite

Coherent acoustic phonons are generated in GaAs/AlAs superlattices by excitation with femtosecond laser pulses. Several modes of the acoustic phonon spectrum are observed, in agreement with the effect of zone folding in the mini-Brillouin zone of the superlattice. By applying successive pump pulses we are able to silence the first back-folded mode near qϭ0, while selectively enhancing the coherent amplitude of higher order backfolded modes. This increase in the spectroscopic sensitivity opens the way to detailed time resolved studies of higher order acoustic modes in superlattices. © 1998 American Institute of Physics. ͓S0003-6951͑98͒02022-1͔The coherent control of elementary optical excitations is one of the key issues in femtosecond technology. This control is enabled by the complete knowledge of the dynamics of quantum mechanical systems concerning amplitude and phase in the time domain. Thus, providing well defined quanta of energy in a well defined temporal sequence a system can be driven into an artificial quantum mechanical state, which cannot be achieved by other means of optical excitation. Presently, strong endeavors are made to coherently control electronic and vibronic excitations in solids, as well as in chemical and biological systems. Coherent control over vibronic excitations has been accomplished in molecular systems, where the amplitude of molecular vibrations was enhanced extremely by exciting the system with a comb of laser pulses spaced by the inverse of the vibrational period. 1In photochemistry, coherent control is pursued in order to sequentially excite certain reaction paths, which would be very improbable in thermodynamic equilibrium.2 In semiconductor heterostructures, the coherent control of electronic excitations has been demonstrated convincingly.3,4 The phase coherence of excitons was used to excite and destruct excitons, thus controlling the carrier population 4 and the emission of THz radiation 3 on a femtosecond time scale. The coherent control of lattice oscillations in solid state materials is an intriguing concept, since the selective manipulation of the amplitude of certain lattice modes allows a detailed study of electron-phonon and phonon-phonon interaction, as well as anharmonicity at large amplitudes. So far, coherent control of LO phonons has been realized in bulk semiconductors in double-pulse experiments, where the careful choice of the excitation parameters led to a complete destructive interference of coherent LO phonons. 5,6 Phase control over degenerate phonon modes has also been achieved recently. 7 Here, we present the first demonstration of coherent control over acoustic phonons in semiconductor superlattices, which, in principle, allows to selectively excite any branch in the phonon dispersion, while suppressing other branches.In the lower frequency range acoustic phonons exhibit a linear dispersion relation ϭv sound q, where v sound is the sound velocity of the material and q the wave vector of the phonon. In artificial superlattices, the acoustic phonon spec...

show abstract

“…The evenly spaced FT line spectrum cannot be attributed to the phonon ladder climbing [6] or the Raman overtone scattering [7], because these processes would produce anharmonic progressions. Our observation of the frequency comb is consistent with the excitation of THz Raman polarization, which modulates the optical constants of Si through the optical deformation potential, as can be explained by an analytical model below.…”

Section: Resultsmentioning

confidence: 99%

Coherent phonon frequency comb generated by few-cycle femtosecond pulses in Si

Hase

Katsuragawa

Constantinescu

et al. 2013

EPJ Web of Conferences

View full text Add to dashboard Cite

Abstract. We explore the coherent phonon induced refractive index modulation of a Si(001) surface upon the excitation in near-resonance with the direct band gap of Si. Through the anisotropic e-h pair generation and coherent Raman scattering, ~ 10-fs laser pulses exert a sudden electrostrictive force on Si lattice launching coherent LO phonon oscillations at 15.6 THz frequency. The concomitant oscillatory change in the optical constants modulates the reflected probe light at the fundamental LO phonon frequency, generating a broad comb of frequencies at exact integer multiples of the fundamental frequency extending to beyond 100 THz. On the basis of an analytical model, we show that the simultaneous amplitude and phase modulation of the reflected light by the coherent lattice polarization at 15.6 THz generates the frequency comb.

show abstract

Direct time-resolved measurement of anharmonic lattice vibrations in ferroelectric crystals

Cited by 46 publications

References 19 publications

Intense ultrashort terahertz pulses: generation and applications

Intense ultrashort terahertz pulses: generation and applications

Coherent control of acoustic phonons in semiconductor superlattices

Coherent phonon frequency comb generated by few-cycle femtosecond pulses in Si

Contact Info

Product

Resources

About