Coherent diffraction and random scattering in thiol-ene–based holographic polymer-dispersed liquid crystal reflection gratings

Bragg diffraction and random scattering in reflective holographic polymer-dispersed liquid crystal gratings are modeled using a matrix approach for a stack of low-high index layer pairs and an effective medium theory. Scattering is due to both random roughness of layer interfaces and random index variations within the layers. These are related to random liquid crystal droplet size and location as well as random orientation of the symmetry axes of bipolar droplets. Characteristic parameters governing coherent diffraction efficiency and random scattering are obtained partly from experiments, where possible, and partly from calculations based on a model of an effective medium applied to the grating. Calculations of grating transmittance are then compared to experimental transmittance spectra. Effects of scattering, primarily a decrease in baseline transmittance with wavelength and a small reduction in diffraction efficiency at the Bragg wavelength, are found to be due primarily to index inhomogeneities withi...

[1]  R. F. Cohn,et al.  Total-internal-reflection mode in holographic polymer dispersed liquid crystals. , 2003, Optics letters.

[2]  R. Sutherland,et al.  Phenomenological model of anisotropic volume hologram formation in liquid-crystal-photopolymer mixtures , 2004 .

[3]  Doane,et al.  Light scattering from a small nematic droplet. , 1986, Physical review. A, General physics.

[4]  Munekazu Date,et al.  Fabrication of Holographic Polymer Dispersed Liquid Crystal (HPDLC) with High Reflection Efficiency , 1999 .

[5]  Miguel A. Rodriguez,et al.  Diffractive properties of highly birefringent volume gratings: investigation , 2002 .

[6]  G. Crawford,et al.  Formation dynamics of diffraction gratings in reactive liquid crystals , 2001 .

[7]  Jun Qi,et al.  Nonlocal photopolymerization effect in the formation of reflective holographic polymer-dispersed liquid crystals , 2004 .

[8]  L. Solymar,et al.  Volume holography and volume gratings , 1981 .

[9]  Ronald T. Smith,et al.  Application-specific integrated filters for color-sequential microdisplay-based projection applications , 2001 .

[10]  Germano Montemezzani,et al.  Light diffraction at mixed phase and absorption gratings in anisotropic media for arbitrary geometries , 1997 .

[11]  Gary Qian,et al.  Organic-based electrically switchable Bragg gratings and their applications in photonics and telecommunications , 2001, SPIE OPTO.

[12]  Allan C. Ashmead,et al.  Switchable Bragg grating devices for telecommunications applications , 2001, SPIE OPTO.

[13]  R. Caputo,et al.  Development of a new kind of switchable holographic grating made of liquid-crystal films separated by slices of polymeric material. , 2004, Optics letters.

[14]  Lalgudi V. Natarajan,et al.  Polarization and switching properties of holographic polymer-dispersed liquid-crystal gratings. II. Experimental investigations , 2002 .

[15]  H. Macleod,et al.  Thin-Film Optical Filters , 1969 .

[16]  J J Butler,et al.  Diffraction properties of highly birefringent liquid-crystal composite gratings. , 2000, Optics letters.

[17]  A. Fontecchio,et al.  Temporally multiplexed holographic polymer-dispersed liquid crystals , 2003 .

[18]  G. P. Crawford,et al.  Improved reflective displays based on polymer-dispersed liquid crystals , 2000 .

[19]  Gregory P. Crawford,et al.  Diffusion kinetics of formation of holographic polymer-dispersed liquid crystal display materials , 2000 .

[20]  Lalgudi V. Natarajan,et al.  Switchable Holographic Polymer-Dispersed Liquid Crystal Reflection Gratings Based on Thiol−Ene Photopolymerization , 2003 .

[21]  Zumer,et al.  Light scattering from nematic droplets: Anomalous-diffraction approach. , 1988, Physical review. A, General physics.

[22]  C. K. Carniglia,et al.  Scalar Scattering Theory for Multilayer Optical Coatings , 1979 .

[23]  Shin‐Tson Wu,et al.  Infrared refractive indices of liquid crystals , 2005 .

[24]  Gregory P. Crawford,et al.  Characterization of holographic polymer dispersed liquid crystal transmission gratings , 2001 .

[25]  T. Rozzi,et al.  Optical and mechanical shrinkage effects in dye-doped photonic bandgap structures based on organic materials. , 2006, Physical review. E, Statistical, nonlinear, and soft matter physics.

[26]  P. Lorrain,et al.  Introduction to Electromagnetic Fields and Waves , 1964 .

[27]  Gregory P. Crawford,et al.  Variable-wavelength switchable Bragg gratings formed in polymer-dispersed liquid crystals , 2001 .

[28]  Z. Kam,et al.  Absorption and Scattering of Light by Small Particles , 1998 .

[29]  J. Qi,et al.  Polymer scaffolding model for holographic polymer-dispersed liquid crystals , 2002 .

[30]  Richard L. Sutherland,et al.  Polarization and switching properties of holographic polymer-dispersed liquid-crystal gratings. I. Theoretical model , 2002 .