title: Photochromic polymers for the optical homodyne detection of ultrasonic surface displacements.
abstract: We present a novel scheme with which to detect small ultrasonic surface displacements by use of a photochromic polymer instead of a photorefractive material as an adaptive beam combiner in a two-wave mixing geometry. Poly(methyl methacrylate) is doped with a derivative of zinc tetrabenzoporphyrin that possesses a long-lived triplet state that can be efficiently populated in a reversible manner. The resulting dynamic hologram consists of local absorption and refractive-index gratings, which can process speckled beams reflected from rough surfaces. We believe that this is the first use of a local nonlinear medium for adaptive homodyne detection of ultrasonic surface displacements.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Gubler
authors.forename: Daniel
authors.initials: D
authors.lastname: Wright
authors.forename: W E
authors.initials: WE
authors.lastname: Moerner
authors.forename: Marvin B
authors.initials: MB
authors.lastname: Klein