Wavelength-Tunable Defect Modes in a Liquid-Crystal-in-Cavity Photonic Structure in the Near-Infrared Region

Yi-Cheng Chang^1*, Guan-Fu Sung², Shun-Yi Chiu³, Yu-Chen Liou⁴, Hsu Chih Yuan⁵, Chin-Pin Yeh⁵, Wei Lee³

¹Institute of Lighting and Energy Photonics, National Yang Ming Chiao Tung University, Tainan, Taiwan
²College of Photonics, National Yang Ming Chiao Tung University, Tainan, Taiwan
³Institute of Imaging and Biomedical Photonics, National Yang Ming Chiao Tung University, Tainan, Taiwan
⁴Institute of Photonic System, National Yang Ming Chiao Tung University, Tainan, Taiwan
⁵Apogee Optocom Co., Ltd, Tainan, Taiwan

* Presenter:Yi-Cheng Chang, email:nick136021@gmail.com

An optical module based on a liquid crystal (LC) layer confined in a resonance cavity is proposed for operation in the near-infrared region. Defect modes within the photonic bandgap (PBG) are generated by alternately coating high- and low-index dielectric media on two glass substrates to produce multilayer films and by subsequently assembling such two identical dielectric mirrors coated with conductive and aligning layers to sandwich the LC defect layer. The wavelengths of the transmitted peaks of the defect modes can be effectively modulated by an applied AC voltage. Characterized by tunable defect-mode wavelengths, compact volume, simple manufacture, stable operation, and low cost, this PBG structure holds great promise for the development of miniature spectrometers.

Keywords: Spectrometer, Liquid Crystal, Photonic Bandgap, Multilayer Film, Defect Modes