title: Photoerasable and photorewritable spatially-tunable laser based on a dye-doped cholesteric liquid crystal with a photoisomerizable chiral dopant.
abstract: This study investigates, for the first time, a photoerasable and photorewritable spatially-tunable laser using a dye-doped cholesteric liquid crystal (DDCLC) with a photoisomerizable chiral dopant (AzoM). UV illumination via a photomask with a transmittance-gradient can create a pitch gradient in the cell such that the lasing wavelength can be spatially tuned over a wide band of 134nm. The pitch gradient is generated by the UV-irradiation-induced gradient of the cis-AzoM concentration and therefore the induced gradient of the cell HTP value, resulting in the spatial tunability of the laser. Furthermore, the laser has advantages of photoerasability and photorewritability. The spatial tunability of the laser can undergo more than 100 cycles of photoerasing and photorewriting processes without decay or damage.
authors.affiliation: Institute of Electro-Optical Science and Engineering and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan 701, Republic of China.
authors.forename: Shih-Hung
authors.initials: SH
authors.lastname: Lin
authors.forename: Cang-Yi
authors.initials: CY
authors.lastname: Shyu
authors.forename: Jui-Hsiang
authors.initials: JH
authors.lastname: Liu
authors.forename: Po-Chih
authors.initials: PC
authors.lastname: Yang
authors.forename: Ting-Shan
authors.initials: TS
authors.lastname: Mo
authors.forename: Shuan-Yu
authors.initials: SY
authors.lastname: Huang
authors.forename: Chia-Rong
authors.initials: CR
authors.lastname: Lee