Schrödinger-type traps for Lamb waves in dynamic potential wells

A dynamic trapping of Lamb modes with a frequency cutoff was achieved through local heating of an elastic plate using a cw laser. The relatively small variations in material stiffness resulting from the temperature rise proved effective at capturing waves within the heated region, which behaved like a potential well for specific Lamb modes. These trapped modes corresponded precisely to discrete frequencies predicted by the time-independent Schrödinger equation, reminiscent of the principle quantum number. The number of trapped modes hinges on both the width and depth of the laser-induced thermal potential well, with these variables interrelated via Heisenberg's uncertainty principle. Furthermore, we observed a high-quality factor ($Q$ factor of approximately 260) attributed to the trapped wave motion within the potential well, offering significant promise for highly precise nondestructive evaluation of thermal and mechanical properties of materials.