Refractive index and absorption coefficient of blue phase liquid crystal in terahertz band

ABSTRACT

The refractive index and absorption coefficient of blue phase liquid crystals are investigated by terahertz time-domain spectroscopy system. Four phases, including isotropic phase, BPII, BPI, and cholesteric phase are investigated. The refractive index of liquid crystal sample is dependent on the temperature, which is related to the different phases. In our experiment, in the frequency range of 0.2–1.2 THz, the refractive index of BPII and BPI is about 1.620 and 1.625, respectively. For BPII and BPI, the measured absorption coefficients increase with the increase of frequency, with absorption peak appearing at 1.11 and 1.05 THz, respectively. These properties of BPLC provide useful information for BPLC-based terahertz components such as phase shifter, wave-plates and so on.

GRAPHICAL ABSTRACT

KEYWORDS:

• Blue phase liquid crystal
• refractive index
• absorption coefficient
• Terahertz

Acknowledgements

This work is supported by National Natural Science Foundation of China (NSFC) (Project Nos. 61405088), Basic Research of Shenzhen Science and Technology Innovation Council (Project No. JCYJ20150601155130435), Shenzhen Overseas High-Level Talent Peacock Team (Project No. KQTD2015071710313656).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is supported by National Natural Science Foundation of China (NSFC) [Project Nos. 61405088], Basic Research of Shenzhen Science and Technology Innovation Council [Project No. JCYJ20150601155130435], Shenzhen Overseas High-Level Talent Peacock Team [Project No. KQTD2015071710313656].