Two-photon absorption is one of a variety of two-photon processes. In this specific process, two photons are absorbed by a sample simultaneously. Neither photon is at resonance with the available energy states of the system. Two-photon absorption may seem very similar to non-resonance Raman, and was in fact predicted due to this phenomena. The invention of the laser had a great impact on the field of two-photon spectroscopy because of the necessity of a high-intensity electromagnetic field to induce transitions.
Related Journals of Two photonabsorption
Journal of Electrical & Electronic Systems, Journal of Physical Chemistry & Biophysics, Advances in Optics and Photonics,Acta Photonica Sinica, IEEE Photonics Journal, IEEE Photonics Technology Letters, Journal of Photonics for Energy, Laser and Photonics Reviews, Nature Photonics.