Control of laser-induced mechanical effects by using a dual-wavelength irradiation method

A straightforward method of controlling laser-induced mechanical effects in biological tissues is to regulate the pulse energy of the irradiating laser. Because the local temperature of the irradiated region rises as the laser’s pulse energy increases, this method cannot independently control purely mechanical effects without changing the thermal effects. Here, a dual-wavelength irradiation method is proposed in which biological tissues are irradiated simultaneously by using two laser pulses with different wavelengths, and laser-induced mechanical effects are continuously controlled with no change in the maximum temperature increase by systematically varying the energy of each laser pulse. The proposed method is analyzed, and its feasibility is demonstrated through numerical simulations.