Surface photoalignment has been utilized to control the liquid crystalline (LC) orientation by exposing the photosensitive surface coatings to linearly polarized light. However, there are limitations in cell thickness and director orientation complexity if surface photoalignment was conducted. An alternative approach in controlling the director orientation is bulk photoalignment. Azobenzenes, which have been used for surface photoalignment due to fast reorientation during exposure, are homogeneously mixed into a nematic LC. We present results on how azobenzene doped LCs can be aligned in various standard orientations. In addition, rewriting alignment and patterning complex director orientations via bulk alignment will be discussed.
Making effective and efficient use of outreach resources can be difficult for student groups in smaller rural communities. Washington State University's OSA/SPIE student chapter desires well attended yet cost-effective ways to educate and inform the public. We designed outreach activities focused on three different funding levels: low upfront cost, moderate continuing costs, and high upfront cost with low continuing costs. By featuring our activities at well attended events, such as a pre-football game event, or by advertising a headlining activity, such as a laser maze, we take advantage of large crowds to create a relaxed learning atmosphere. Moreover, participants enjoy casual learning while waiting for a main event. Choosing a particular funding level and associating with well-attended events makes outreach easier. While there are still many challenges to outreach, such as motivating volunteers or designing outreach programs, we hope overcoming two large obstacles will lead to future outreach success.
High intensity laser stimulation induces stress in dye-doped photomechanical elastomers, causing a length change. Using principles of nonlinear optics and continuum mechanics, we develop a theoretical model quantifying how these elastomers react to laser stimulation. The model evaluates the quality of the response using a photomechanical coefficient, such that a larger coefficient means a larger stress, and hence a more highly photoresponsive material. We are able to determine the photoresponsiveness as a function of pre-strain, laser intensity, strain his- tory, and other properties. Furthermore, we test our model with various types of elastomers, as well as different dyes and doping agents.
Several organic dyes have been shown to self heal when doped in a polymer matrix. Most measurements to date
use optical absorbance, amplified spontaneous emission, or digital imaging as a probe. Each method determines a
subset of the relevant parameters. We have constructed a white light interferometric microscope, which measures
the absorption spectrum and change in refractive index during decay and recovery simultaneously at multiple
points in the material. We report on preliminary measurements and results concerning the microscopes spatial