Characterization of Second-Order Reflection Bands from a Cholesteric Liquid Crystal Cell Based on a Wavelength-Swept Laser

We report the results of an experimental study of the characterization of second-order reflection bands from a cholesteric liquid crystal (CLC) cell that depends on the applied electric field, using a wide bandwidth wavelength-swept laser. The second-order reflection bands around 1300 nm and 1500 nm were observed using an optical spectrum analyzer when an electric field was applied to a horizontally oriented electrode cell with a pitch of 1.77 μm. A second-order reflection spectrum began to appear when the intensity of the electric field was 1.03 Vrms/μm with the angle of incidence to the CLC cell fixed at 36°. The reflectance increased as the intensity of the electric field increased at an angle of incidence of 20°, whereas at an incident angle of 36°, when an electric field of a predetermined value or more was applied to the CLC cell, it was confirmed that deformation was completely formed in the liquid crystal and the reflectance was saturated to a constant level. As the intensity of the electric field increased further, the reflection band shifted to a longer wavelength and discontinuous wavelength shift due to the pitch jump was observed rather than a continuous wavelength increase. In addition, the reflection band changed when the angle of incidence on the CLC cell was changed. As the angle of incidence gradually increased, the center wavelength of the reflection band moved towards shorter wavelengths. In the future, we intend to develop a device for optical wavelength filters based on side-polished optical fibers. This is expected to have a potential application as a wavelength notch filter or a bandpass filter.

[1]  Petr Shibaev,et al.  Distant mechanical sensors based on cholesteric liquid crystals , 2012 .

[2]  Heinz-S. Kitzerow,et al.  Chirality in Liquid Crystals , 2013 .

[3]  Leonas Dumitrascu,et al.  The influence of the external electric field on the birefringence of nematic liquid crystal layers , 2006 .

[4]  Jie Xiang,et al.  Electrically Tunable Selective Reflection of Light from Ultraviolet to Visible and Infrared by Heliconical Cholesterics , 2015, Advanced materials.

[5]  Jun Zhang,et al.  High-Speed and Wide Bandwidth Fourier Domain Mode-locked Wavelength Swept Laser with Multiple SOAs , 2007, 2007 Conference on Lasers and Electro-Optics - Pacific Rim.

[6]  Ryotaro Ozaki,et al.  Simple model for estimating band edge wavelengths of selective reflection from cholesteric liquid crystals for oblique incidence. , 2019, Physical review. E.

[7]  Myeong Ock Ko,et al.  In situobservation of dynamic pitch jumps of in-planar cholesteric liquid crystal layers based on wavelength-swept laser. , 2018, Optics express.

[8]  Timothy J White,et al.  Reflection spectra of distorted cholesteric liquid crystal structures in cells with interdigitated electrodes. , 2014, Optics express.

[9]  R. Hikmet,et al.  Electrically switchable mirrors and optical components made from liquid-crystal gels , 1998, Nature.

[10]  Yong Li,et al.  Full-color reflective display based on narrow bandwidth templated cholesteric liquid crystal film , 2017 .

[11]  S P Palto,et al.  Spectral and polarization structure of field-induced photonic bands in cholesteric liquid crystals. , 2015, Physical review. E, Statistical, nonlinear, and soft matter physics.

[12]  Vincent P. Tondiglia,et al.  Large range electrically-induced reflection notch tuning in polymer stabilized cholesteric liquid crystals , 2015 .

[13]  Ronald Sroka,et al.  Bandwidth-variable tunable optical filter unit for illumination and spectral imaging systems using thin-film optical band-pass filters. , 2013, The Review of scientific instruments.

[14]  Michel Mitov,et al.  Going beyond the reflectance limit of cholesteric liquid crystals , 2006, Nature materials.

[15]  Lalgudi V. Natarajan,et al.  Electrically Induced Color Changes in Polymer‐Stabilized Cholesteric Liquid Crystals , 2013 .

[16]  G. W. Gray,et al.  Physical Properties of Liquid Crystals , 2003 .

[17]  Yo Inoue,et al.  Faster pitch control of cholesteric liquid crystals , 2017 .

[18]  Timothy J White,et al.  Optically switchable, rapidly relaxing cholesteric liquid crystal reflectors. , 2010, Optics express.

[19]  Masahiko Hara,et al.  Experimental Study on Higher Order Reflection by Monodomain Cholesteric Liquid Crystals , 1983 .

[20]  John W. Goodby,et al.  Chiral Nematics: Physical Properties and Applications , 2008 .

[21]  J. W. Doane,et al.  Control of reflectivity and bistability in displays using cholesteric liquid crystals , 1994 .

[22]  Gia Petriashvili,et al.  Paper like cholesteric interferential mirror. , 2013, Optics express.

[23]  Heinz-S. Kitzerow,et al.  Electrical fine tuning of liquid crystal lasers , 2012 .

[24]  Shin-Tson Wu,et al.  Transflective liquid crystal displays , 2010, Journal of Display Technology.

[25]  Michel Mitov,et al.  Cholesteric Liquid Crystals with a Broad Light Reflection Band , 2012, Advanced materials.

[26]  Haiqing Xianyu,et al.  In-plane switching of cholesteric liquid crystals for visible and near-infrared applications. , 2004, Applied optics.

[27]  Mi-Yun Jeong,et al.  Continuous spatial tuning of laser emissions with tuning resolution less than 1 nm in a wedge cell 
of dye-doped cholesteric liquid crystals. , 2010, Optics express.

[28]  Mi-Yun Jeong,et al.  Continuously tunable optical notch filter and band-pass filter systems that cover the visible to near-infrared spectral ranges. , 2018, Applied optics.

[29]  Michel Mitov,et al.  Theoretical and experimental optical studies of cholesteric liquid crystal films with thermally induced pitch gradients. , 2006, Physical review. E, Statistical, nonlinear, and soft matter physics.

[30]  Robert B. Meyer,et al.  Effects of a magnetic field on the optical transmission in cholesteric liquid crystals , 1972 .

[31]  Myeong Ock Ko,et al.  Dynamic measurement for electric field sensor based on wavelength-swept laser. , 2014, Optics express.