Large amplitude vibration of a cantilever actuated by a high-frequency pulsed laser.

Laser excitation based on the thermoelastic principle is effective for micro-scale actuation, enabled energy conversion from optical to mechanical. The major advantages lie in non-contact actuation, easy miniaturization, and integration. To avoid surface damage, the laser power per unit is limited, leading to several micrometers of the vibration. In this study, a pure nickel millimeter-sized cantilever is successfully actuated at a low-frequency resonance (around Hz) via a nanosecond pulsed laser. By modal interaction, the energy is transferred from a low-intensity, high-frequency (around kHz) excitation to a low-frequency response with millimeter amplitude. The stable low-frequency resonance of the cantilever was maintained by changing the laser pulse parameters and the illumination locations. We also present a method to control the vibration of the cantilever using a modulated wave (MW: the laser wave modulated by a rectangular wave). The cantilever's amplitude can be efficiently adjusted by changing the laser power or duty cycle of the MW. The resonance frequency of the cantilever also can be altered by optimizing the geometries to meet various actuation requirements. This study enables large actuation (up to tens of millimeters) by laser excitation, facilitating applications in precision manipulation, microfluidic mixing, lab-on-a-chip device, and other related micro actuation devices.