Optical edge modes in photonic liquid crystals |
| |
Authors: | V A Belyakov and S V Semenov |
| |
Institution: | (1) X-ray Optics Section, Raja Rammana Centre For Advanced Technology, Indore, 452013, India;(2) Department of Astronomy & Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, 400005, India |
| |
Abstract: | An analytic theory of localized edge modes in chiral liquid crystals (CLCs) is developed. Equations determining the edge-mode
frequencies are found and analytically solved in the case of low decaying modes and are solved numerically for the problem
parameter values typical for the experiment. The discrete edge-mode frequencies specified by the integer numbers n are located close to the stop-band edge frequencies outside the band. The expressions for the spatial distribution of the
n’s mode field in a CLC layer and for its temporal decay are presented. The possibilities of a reduction of the lasing threshold
due to the anomalously strong absorption effect are theoretically investigated for a distributed feedback lasing in CLCs.
It is shown that a minimum of the threshold pumping wave intensity may be reached, generally, for the pumping wave propagating
at an angle to the helical axis. However, for lucky values of the related parameters, it may be reached for the pumping wave
propagating along the helical axis. The lowest threshold pumping wave intensity occurs for the lasing at the first low-frequency
band-edge lasing mode and the pumping wave propagating at an angle to the spiral axis corresponding to the first angular absorption
maximum of the anomalously strong absorption effect at the high-frequency edge of the stop band. The study is performed in
the case of the average dielectric constant of the liquid crystal coinciding with the dielectric constant of the ambient material.
Numerical calculations of the distributed feedback lasing threshold at the edge-mode frequencies are performed for typical
values of the relevant parameters. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|