Self-diffraction studies in a-se-nematic liquid crystal cell

✍ Scribed by A. Januszko; A. Miniewicz

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 500 KB
• Volume: 6
• Category: Article
• ISSN: 1616-301X
• DOI: 10.1002/(sici)1099-0712(199609)6:5/6<272::aid-amo261>3.0.co;2-4

✦ Synopsis

We report the results of self-diffraction measurements in nematic liquid crystal films under the combined action of an applied DC electric field and an impinging optical field. The presence of self-diffraction in a two-wave-mixing experiment with low-power laser light is proof that the material is capable of forming index-of-refraction gratings and can be used for dynamic holography purposes. The liquid crystal cells used in our experiments were filled with 4- cyano-4'-pentyl-biphenyl (5CB). The transparent IT0 electrodes were covered with amorphous selenium (u-Se) as a photocarrier generation layer. Photoinjection of charge carriers accompanied by space charge field formation together with the DC applied field leads to a refractive index change in the nematic liquid crystal through a field-induced director axis reorientation. Measurements of self-diffraction efficiencies under various experimental conditions allowed us to establish optimised sample configurations for hologram recording.