CHANGE OF INDUCED STRESS WAVE ON COLLAGEN TISSUE FOR BIOSTIMULATION BY FREQUENCY-DOUBLED Nd:YAG LASER

In this research, thermoelastic effect was investigated for biostimulation without damage on the biological medium using laser. Thermoelastic effect was generated and mechanical stress was induced by laser irradiation on the collagen, the main protein in the human body, under various conditions with short pulsed laser. The threshold laser energy to induce stress wave in each medium thickness was examined with a piezo sensor. Based on the test, the stimulation strength can be controlled through the adjustment of medium thickness, laser energy and beam diameter. The result implies that precise stimulation with various strengths of stress waves can be generated at the target depth without direct contact with the biological medium. This research can be used valuably in various fields such as contactless biostimulation, low power laser treatment and laser haptic applications.