Dynamics of the light-induced structural phase transition in confining gallium and associated gigantic optical nonlinearity

Summary form only given. We report on a study of the nanosecond dynamics of a recently discovered light-induced, surface-assisted structural phase transition from a common orthorhombic phase of /spl alpha/-gallium to a highly reflective phase. The transition has been observed at temperatures just below the metal´s bulk melting point (30/spl deg/C). It is fully reversible with dynamics occurring on a nanosecond/microsecond time scale and can be stimulated by radiation of a very low intensity, typically 10/sup -4/-10/sup -5/ W//spl mu/m/sup 2/. The two gallium phases involved in the transition have significantly different optical properties which gives rise to a gigantic optical nonlinearity, /spl chi//sup (3)//spl sim/1 esu offering tremendous new opportunities in controlling light with light.