Ultrasonic Beam Mixing as a Measure of the Nonlinear Parameters of Fused Silica and SingleCrystal NaCl
Abstract
The mixing action of two crossed ultrasonic beams has been studied. The theoretical treatment of Taylor and Rollins is extended to include the allpuremode cases for the prosess L (ω_{1})Tω_{2}ω_{1} ω_{2}>Tω_{1} ω_{2}ω_{2} in cubic single crystals. Five such cases exist in cubic crystals; two in the (001) mixing plane and with L (ω_{1}) propagated in either of two fixed directions [100] and [110]; and the other three in the (11̄0) mixing plane and with L (ω_{1}) propagated in any of three fixed directions [110], [111], and [001]. The transverse waves are polarized normal to the mixing plane in all five cases and propagate in directions within the plane corresponding to the selection rules on frequency and propagation vector. The conversion efficiency was measured over a range of input frequency ratios, a=ω_{2}ω_{1} for the two independent transversepolarization states for the above process in fused silica and for the two puremode cases in the (001) plane in NaCl. A comparison technique using the interchange equivalence of T(ω_{2}) and T(ω_{1}ω_{2}) effectively eliminated the transducerbond efficiencies. These measurements were used to determine two of the three independent thirdorder elastic constants of fused silica. In the case of NaCl, the two ratios of linear combinations of second and thirdorder elastic constants corresponding to the two (001) plane puremode cases were determined. The above comparison technique was not applied to the other three puremode cases because the transverse anisotropy in the (11̄0) plane leads to refractive effects on the transverse beams that render the technique inapplicable.
 Publication:

Physical Review B
 Pub Date:
 August 1970
 DOI:
 10.1103/PhysRevB.2.1098
 Bibcode:
 1970PhRvB...2.1098D