title: Dynamic holography in bacteriorhodopsin/gelatin films: effects of light-dark adaptation at different humidity.
abstract: This work examines the kinetics of dynamic holography responses in light-adapted and dark-adapted bacteriorhodopsin (BR) films at different humidity. We have demonstrated that the kinetics of the diffraction efficiency in wild type BR films is quite different in dark-adapted and light-adapted samples. The holographic recording kinetics, which depends on the duration of incubation in the dark after light adaptation at different humidity values, was studied in depth. A specially designed miniature cell containing a BR film was mounted inside the holographic set up to allow controlled humidity changes over a broad range. The diffraction efficiency kinetics at humidity values of 96-99% were quite different from the kinetics at 60-93% humidity. We found that humidity values of 90-93% were most optimal for dynamic holography recording using a gelatin film containing BR. In agreement with a calculation of the wavelength-dependent changes of the refractive index for dark-adapted and light-adapted BR samples using the Kramers-Kronig relation, the maximum difference in the refractive index and thus in the diffraction efficiency for dark-adapted and light-adapted BR films takes place at 630 nm, close to the wavelength of the He-Ne laser used.
authors.affiliation: Institute of Physics, National Academy of Sciences, Kiev, Ukraine. elkorch@iop.kiev.ua
authors.forename: Elena
authors.initials: E
authors.lastname: Korchemskaya
authors.forename: Nikolai
authors.initials: N
authors.lastname: Burykin
authors.forename: Svitlana
authors.initials: S
authors.lastname: Bugaychuk
authors.forename: Olena
authors.initials: O
authors.lastname: Maksymova
authors.forename: Thomas
authors.initials: T
authors.lastname: Ebrey
authors.forename: Sergei
authors.initials: S
authors.lastname: Balashov
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry* / Q000528:radiation effects*; D003624:Darkness; D005780:Gelatin; D019617:Halobacterium salinarum / Q000737:chemistry; D006696:Holography; D006813:Humidity; D008027:Light; D008567:Membranes, Artificial; D055095:Optics and Photonics; D010777:Photochemistry
chemical_list: D008567:Membranes, Artificial; D001436:Bacteriorhodopsins; D005780:Gelatin