Mi-Yun Jeong
Gyeongsang National University, Korea
Title: In-situ study on optical properties and continuous laser tuning in cholesteric liquid crystal laser array
Biography
Biography: Mi-Yun Jeong
Abstract
Cholesteric liquid crystals (CLCs) have become promising candidates for photonic crystal laser devices owing to their unique optical characteristics in mirror less lasing, as well as micron-sized thickness, low threshold, and lasing tunability in the full visible spectral range. In this paper, we introduced in-situ study on optical properties and continuous laser wavelength tuning in cholesteric liquid crystal laser array. General and polymerized CLC laser devices were fabricated to have fine-structured pitch gradient in a wedge CLC cell and to have tuning resolution less than 0.3 nm in abroad spectral range. The comprehensive optical properties of the laser lines and fluorescent spectrum generated by a CLC laser array were studied; the laser lines generated from a CLC with a right-(left-) handed circular helix were right-(left-) handed circular polarized, respectively. We found out that inside the photonic band gap, the CLC structure with right-(left-) handed helicity suppressed the fluorescence generated with right (left) circular polarized light, and instead the suppressed right (left) circular polarized light energy moved to the outside of the photonic band gap, so we can say that the fluorescence intensity outside of the photonic band gap is enhanced with right (left) handed circular polarized light. Depending on the position of the photonic band gap, the fluorescence quantum yield value increased by up to ~15%. And the polymerized CLC devices had good stability for a time of more than 1 year, and in response to strong external laser light sources, and thermal perturbation. And dynamic laser tuning by electric field and temperature control were also studied.
