title: Broadly defining lasing wavelengths in single bandgap-graded semiconductor nanowires.
abstract: Designing lasing wavelengths and modes is essential to the practical applications of nanowire (NW) lasers. Here, according to the localized photoluminescence spectra, we first demonstrate the ability to define lasing wavelengths over a wide range (up to 119 nm) based on an individual bandgap-graded CdSSe NW by forward cutting the NW from CdSe to CdS end. Furthermore, free spectral range (FSR) and modes of the obtained lasers could be controlled by backward cutting the NW from CdS to CdSe end step-by-step. Interestingly, single-mode NW laser with predefined lasing wavelength is realized in short NWs because of the strong mode competition and increase in FSR. Finally, the gain properties of the bandgap-graded NWs are investigated. The combination of wavelength and mode selectivity in NW lasers may provide a new platform for the next generation of integrated optoelectronic devices.
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation, Department of Optical Engineering, Zhejiang University , Hangzhou 310027, China.
authors.forename: Zongyin
authors.initials: Z
authors.lastname: Yang
authors.forename: Delong
authors.initials: D
authors.lastname: Wang
authors.forename: Chao
authors.initials: C
authors.lastname: Meng
authors.forename: Zhemin
authors.initials: Z
authors.lastname: Wu
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Yaoguang
authors.initials: Y
authors.lastname: Ma
authors.forename: Lun
authors.initials: L
authors.lastname: Dai
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Liu
authors.forename: Tawfique
authors.initials: T
authors.lastname: Hasan
authors.forename: Xu
authors.initials: X
authors.lastname: Liu
authors.forename: Qing
authors.initials: Q
authors.lastname: Yang