MPM employs a laser that produces short pulses of light, typically in the near-infrared range. These photons have lower energy, allowing them to penetrate deeper into biological tissues. When two or more of these photons interact simultaneously with a fluorophore, they excite it to a higher energy state. Upon returning to the ground state, the fluorophore emits light at a different wavelength, which is then detected to create an image. This process is known as non-linear optics.
