Two photon photovoltaic effect

Two-photon photovoltaic effect is an energy harvesting technique based on two-photon absorption. The effect occurs when two photons are absorbed simultaneously in a semiconductor material and give rise to an electron-hole pair. The photon-generated electron and hole are then collected for electrical power generation using a p-n junction diode. The two-photon photovoltaic effect can be considered as the nonlinear equivalent of the conventional photovoltaic effect commonly used in p-n junction solar cells. The effect was first discovered in silicon and later observed in gallium arsenide and has potential in achieving energy-efficient electronic-photonic integrated circuits.