Hydrostatic pressure response of polymer-dispersed liquid crystal gratings

Experimental analysis showed shifts in Bragg wavelength when examining the effects of applied hydrostatic pressure (0-10 psi above ambient) on the reflection spectrum of holographic polymer-dispersed liquid-crystal Bragg gratings. With increased pressure, a spectral blueshift was observed, suggesting applications in optical pressure sensing. To analyze and quantify the observations, a Gaussian curve was fitted to the reflection spectrum of the gratings at each pressure interval. The spectral dependence on applied pressure is explained by elastic compression of the polymer sections of the Bragg planes in the reflection grating. The presented theory shows that the response of the gratings to the applied pressure is independent of the probe light incidence angle, but is linearly dependent on the ambient pressure reflection wavelength of the gratings. (c) 2005 American Institute of Physics.