Two techniques for suppressing of antisymmetric Lamb wave by two laser beams in a thin plate

We present two suppressing techniques of the antisymmetric mode by superposition of Lamb waves generated by two laser beams in a thin plate. The first method is to generate single mode Lamb waves by two symmetric laser beams quasi-simultaneously hit at the same points of both sides of the plate. The second method is to suppress antisymmetric mode by superposition of Lamb waves generated by two laser beams on one side of a thin plate.