Conversion Excitation of Intense Sound Fields in Crystals
2014
scientific article
english
- elastic wave
- resonance reflection
- conversion
- pump wave
- anisotropy
- diffraction divergence
EN The resonant excitation of an intense elastic wave in a crystal is described through a special nonspecular reflection close to a conversion when almost all the energy from the incident pump wave falls into the near-surface narrow high-intensity reflected beam. The resonance arises when the excited reflected wave is close to the bulk eigenmode satisfying the condition of free boundary. It is shown that the choice of the crystal surface parallel to a symmetry plane allows simultaneous optimization of reflection geometry when the intensity maximum for the excited wave is accompanied by the intensity minimum for the other (parasite) reflected wave. And the conversion criterion of vanishing of the above minimum is determined by one definite condition on elastic moduli. On this basis the series of real monoclinic, orthorhombic and hexagonal crystals were chosen where the resonant reflection in non-symmetric sagittal planes proves to be very close to conversion.
13 - 20
CC BY (attribution alone)
public
5