Electron-hole competition in photorefractive rubidium-doped KNbO3 crystals

This paper reports a novel phenomenon in photorefractive rubidium doped potassium niobate crystals, two different two-beam coupling processes with opposite gain signs and two response time with a difference of two orders of magnitude are observed in a rubidium doped KNbO3 crystal. Which can be explained well by the electron-hole competition.