Infrared-phonon-polariton resonance of the nonlinear susceptibility in GaAs
Infrared-phonon-polariton resonance of the nonlinear susceptibility in GaAs
Dekorsy, T.; Yakovlev, V. A.; Seidel, W.; Helm, W.; Keilmann, F.
Nonlinear probing of the fundamental lattice vibration of polar crystals is shown to reveal insight into higher-order cohesive lattice forces. With a free-electron laser tunable in the far infrared we experimentally investigate the dispersion of the second-order susceptibility due to the phonon resonance in GaAs. We observe a strong resonance enhancement of second harmonic light generation at half the optical phonon frequency, and in addition a minimum at a higher frequency below the phonon frequency. Measuring this frequency and comparison to a theoretical model allows the determination of competing higher-order lattice forces.
Keywords: nonlinear optics; SHG; THz; GaAs; phonon-polariton
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Physical Review Letters 90 (2003) 055508
DOI: 10.1103/PhysRevLett.90.055508
Cited 6 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-5331