Vassilios Albanis

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The gallium/silica interface optical nonlinearity associated with a light-induced structural phase transition from a-gallium to a more reflective, more metallic phase shows an exceptionally broadband spectral response. It allows 40% deep nanosecond/microsecond cross-wavelength intensity modulation between signals at 1.3 and 1.55aem.
We employ an acousto-optic cell as a tunable-pitch wavefront sensor and study its performance. The index of refraction of two cross-standing waves forms, in the near field, an adjustable array of caustics. These caustics, similar to the lenslets used for Hartmann-Shack sensing, were measured to have an extended focal relief of 200 times their pitch. We(More)
The reflectivity of a gallium/silica interface formed on an optical flat or at the tip of a cleaved optical fiber can be reduced in a reversible fashion when the interface is excited by a few milliwatts of laser power. This phenomenon occurs at temperatures just below gallium's melting point. We believe that the effect can be attributed to light-induced(More)
Transient pump-probe measurements of circular anisotropy in nickel films induced by 38-fs optical pulses show an instantaneous response that is related to the optical orientation of the spins of free electrons. Measurements in a sample of variable thickness, performed in both transmission and reflection, revealed that the surface significantly influences(More)
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