Nonresonance Phase Conjugation of Light in Optically Pumped ZnO Films

The possibility of the nonresonance phase conjugation of light occurring in an excited semiconductor medium is shown theoretically and experimentally. In epitaxial ZnO films pumped with a nitrogen laser at room temperature, the induced phase conjugation of light in the visible and infrared spectral regions is detected. The dependences of the phase-conjugation signal intensity on the incident photon energy and laser-pumping intensity are studied. Interpretation of the effect as a result of the absorption and refraction of light at laser-induced free charge carriers in the semiconductor medium is proposed.