Sub-terahertz on–off switch based on a two-dimensional photonic crystal infiltrated by liquid crystals

• Published in: Optics communications Vol. 281; no. 18; pp. 4623 - 4625
• Main Authors: Ghattan, Z., Hasek, T., Wilk, R., Shahabadi, M., Koch, M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.09.2008; Elsevier Science
• Subjects: Applied classical electromagnetism; Electromagnetic wave propagation, radiowave propagation; Electromagnetism; electron and ion optics; Exact sciences and technology; Field-induced rotation; Fundamental areas of phenomenology (including applications); Liquid crystals; Nematic liquid crystals; On–off switch; Optical materials; Optics; Photonic bandgap materials; Photonic crystals; Physics; Sub-terahertz waves; Field-induced rotation; 41.20.Jb; Sub-terahertz waves; On–off switch; 42.79.Gn; 42.70.Qs; Nematic liquid crystals; Photonic crystals; Two dimensional structure; Electromagnetic wave transmission; Experimental study; TM mode; Liquid crystals; Nematic crystals; Polarization mode; THz range; Molecular orientation; Electric field effects; Benzenic compound; On-off switch; Organic compounds
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2008.05.041

A sub-terahertz switch is realized by infiltration of a two-dimensional photonic crystal (PC) with the liquid crystal 5CB. On–off switching is based on a shift of the bandgap of the PC by applying an external electric field which rotates the 5CB molecules. We confirm theoretically and experimentally that rotating the optical axis of the 5CB molecules considerably affects the transmission of the electromagnetic waves of TM polarization in the stop band. The effect can be used for on–off switching of the electromagnetic waves in the sub-terahertz range. Experimentally we demonstrate an extinction ratio of 13.3 dB at 91 GHz.