α 2 (ω 1; ω 2) is the ND-2PA coefficient for optical frequencies ω 1,2 and their associated irradiances I 1,2, E p is the Kane energy parameter, E gap is the bandgap energy, n 1,2 are the refractive ...
Two-photon absorption (2PA) is a third-order non-linear optical process in which a molecule simultaneously absorbs two photons of lower energy to reach an excited electronic state. This phenomenon has ...