Raman Scattering Process (IMAGE) Washington University in St. Louis Caption Raman scattering process: A photon with shorter wavelength from a "pump" laser loses portion of its energy for being scattered by silica molecules and is converted to a 'signal' photon of longer wavelength (labelled as Raman signal) together with a "phonon." Sum of the energies of the signal photon and the phonon equals to the energy of the pump photon. Signal photons inside the whispering-gallery-mode resonator are then coherently amplified leading to Raman laser. Credit J. Zhu, B. Peng, S.K. Ozdemir, L. Yang Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.