Persistent and reversible all-optical phase control in a manganite thin film.

Persistent and reversible optical phase control has been achieved in a manganite thin film through a careful choice of the composition of Pr1-x(Ca1-ySr(y))xMnO3 near a multicritical point. Pulsed laser light brings the lower temperature metallic phase out of the higher temperature charge-ordered insulator, while a cw light reverses the effect by heating. We clearly demonstrate the two competing roles played by light, heating, and excitation across the charge gap, which are important in both the application and the understanding of the physics of electron correlation.