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Reflection hologram recording in DuPont HRF-800X071-20 photopolymer films has been demonstrated by use of pulsed laser exposure with pulse lengths of 25 ns. An expected weak reflectance of the recorded mirror holograms could be significantly increased by preillumination. Although pulsed preillumination enhanced only the reflectance, continuous incoherent preillumination significantly increased both the diffraction efficiency (which reached ~80%) and the sensitivity (which reached an increase of ~100 times, thus approaching the sensitivity of cw recording). The results are compared with those for hologram recordings obtained with cw exposure under the same processing conditions. Spectral absorbance curves of recorded holograms are presented, and possible mechanisms of hologram formation are discussed.

(Rrcrived 3 April 1995 by D. Van qVck)a-SiO, films of varying stoichiometr)r have been prepared by low temperature plasma enhanced chemical vapor deposition.The majority of films showed photoluminescence (PL) and films prepared in a narrow range of gas flows exhibited much stronger PL after annealing. Peak PL energies ranging from the ultraviolet to the near infrared have been observed. PL, infrared and X-ray diffraction on selected samples indicate formation of Si clusters in the films. The effects of annealing on the PL properties of the fdms have been found to depend on initial stoichiometry of the films.

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