Parametric amplification of optical phonons
| Autor: | Michael Fechner, Tobia F. Nova, Andrea Cartella, Roberto Merlin, Andrea Cavalleri |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Physics
Condensed Matter - Materials Science Phase transition Multidisciplinary Phonon Oscillator strength Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences Physics::Optics 02 engineering and technology Optical field 021001 nanoscience & nanotechnology 01 natural sciences Wavelength Condensed Matter::Materials Science Lattice (order) 0103 physical sciences Physical Sciences Density functional theory Atomic physics 010306 general physics 0210 nano-technology Optics (physics.optics) Physics - Optics Parametric statistics |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America |
| Popis: | Amplification of light through stimulated emission or nonlinear optical interactions has had a transformative impact on modern science and technology. The amplification of other bosonic excitations, like phonons in solids, is likely to open up new remarkable physical phenomena. Here, we report on an experimental demonstration of optical phonon amplification. A coherent mid-infrared optical field is used to drive large amplitude oscillations of the Si-C stretching mode in silicon carbide. Upon nonlinear phonon excitation, a second probe pulse experiences parametric optical gain at all wavelengths throughout the reststrahlen band, which reflects the amplification of optical-phonon fluctuations. Starting from first principle calculations, we show that the high-frequency dielectric permittivity and the phonon oscillator strength depend quadratically on the lattice coordinate. In the experimental conditions explored here, these oscillate then at twice the frequency of the optical field and provide a parametric drive for lattice fluctuations. Parametric gain in phononic four wave mixing is a generic mechanism that can be extended to all polar modes of solids, as a new means to control the kinetics of phase transitions, to amplify many body interactions or to control phonon-polariton waves. |
| Databáze: | OpenAIRE |
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