title: Two-photon excited highly polarized and directional upconversion emission from slab organic crystals.
abstract: Effective upconversion emission from an organic crystal of cyano-substituted oligo (p-phenylenevinylene) (CNDPASDB) based on two-photon absorption is presented. Frequency upconverted cavityless lasing, or amplified spontaneous emission, from the crystal pumped by a femtosecond laser of 800 nm was observed when the excitation energy exceeded the threshold of 1.3 mJpulse(-1)cm(-2). Its polarization contrast was estimated to be approximately 0.93. This large ratio is due to the unified unidirectional configuration of the molecular long axis in crystal, beneficial to the stimulated emission with a low threshold. These results indicate that the present CNDPASDB crystal has a potential for upconversion laser device application.
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University,2699 Qianjin Street, Changchun 130012, China.
authors.forename: Hong-Hua
authors.initials: HH
authors.lastname: Fang
authors.forename: Qi-Dai
authors.initials: QD
authors.lastname: Chen
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.forename: Hong
authors.initials: H
authors.lastname: Xia
authors.forename: Yu-Guang
authors.initials: YG
authors.lastname: Ma
authors.forename: Hai-Yu
authors.initials: HY
authors.lastname: Wang
authors.forename: Hong-Bo
authors.initials: HB
authors.lastname: Sun