Second harmonic generation (SHG) is a nonlinear optical process where two photons of the same frequency interact with a nonlinear material, resulting in the production of a new photon with double the energy and half the wavelength. This phenomenon is commonly observed in crystals like beta barium borate (BBO) and potassium titanyl phosphate (KTP), which are used in various applications, including laser technology. In SHG, the input light, typically from a laser, is converted into light at a higher frequency. This process is essential in generating ultraviolet light from infrared lasers, enabling advancements in fields such as telecommunications, medical imaging, and materials science.