SHG

SHG, or Second Harmonic Generation, is a nonlinear optical process where intense light passing through certain materials produces new light at exactly double the frequency (or half the wavelength) of the original. Essentially, it converts two photons of the same frequency into a single photon with twice the energy. This phenomenon is widely used in laser technology and in imaging techniques like microscopy. SHG depends on the material's properties and the intensity of the incoming light, making it a valuable tool for exploring structures at microscopic levels without damaging the sample.