Multipoint Nanolaser Array in an Individual Core–Shell CdS Branched Nanostructure

Abstract

Nanoscale laser arrays are attractive for their potential applications in highly integrated nanodevices, which are always obtained by nanowire arrays with complicated fabrication techniques. Here, a quite different nanolaser array is successfully realized based on a highly ordered core–shell CdS branched nanostructure with implanted Sn nanoparticles in junctions that split the individual multichannel nanostructures to various microcavities with effective light confinement and oscillation, thus to achieve a multipoint nanolaser array. Under the excitation of an ultraviolet laser, the strong band‐edge emission can be well reflected between Sn nanoparticles at junctions and effectively scattered into branch segments due to Sn nanoparticles existence in junctions, furthermore oscillating in various microcavities along trunks or branches to form multipoint lasing from Fabry‐Pérot (F‐P) mode with a quality factor up to 990 and the low threshold at around 3.78 MW cm−2. The corresponding fluorescent microscope images further demonstrate the formation of multipoint F‐P lasing at various segments. The theoretical simulation indicates that implanted Sn nanoparticles work as hot point to enhance the confinement of light around the Sn centers. The existence of surface plasmon from the Sn metal particles is further confirmed by the polarization dependent photoluminescence measurement. The results provide a new way to realize nanolaser arrays.

Hyperbranched Microwire Networks of Organic Cocrystals with Optical Waveguiding and Light‐Harvesting Abilities

“…Conceptually,t hese well-organized, singlecrystalline hyperbranched MWs may be used as miniaturized optical waveguide elements. [10,[45][46][47] Thep hoton transport behavior of branching (2:1)10Ft:BAM Ws were preliminarily examined by amicro-PL equipment equipped with a405 nm continuous wave (CW) laser. As displayed in Figure 5a,t he laser beams were focused onto as ingle two-level branched MW in ad irection perpendicular to the quartz substrate.T he corresponding bright-field optical (Figure 5b)a nd fluorescence microscopy images (Figure 5c)r eveal its highly crystalline character and aligned branches.U pon localized excitation of the trunk/ trunk junction Iw ith the CW laser (Figure 5d), green light propagates following two pathways:1) travels along the two trunks and directly emit from their tips;2 )travels along one trunk and…”

Optical and Optoelectronic Performances of Quasi-Rectangular Cross-Sectional Sn-Doped CdS Nanowires

“…The plot clearly exhibits nonlinear behavior, and the lasing threshold is determined to be about 11.3 mW/cm 2 , which depicts the transition from the spontaneous emission to the stimulated emission. Moreover, because of the low density of defects of the synthesized rectangular cross-sectional nanowire, the lasing threshold is much lower than the other reported Sn-doped nanostructure, such as comb-like branched nanostructure . As known, the lasing mode can be well modulated by the shape of nanostructure, so in the end, we compared the lasing behavior of the Sn-doped CdS nanowire with rectangular and hexagonal shaped cross section.…”

“…Moreover, because of the low density of defects of the synthesized rectangular cross-sectional nanowire, the lasing threshold is much lower than the other reported Sndoped nanostructure, such as comb-like branched nanostructure. 33 As known, the lasing mode can be well modulated by the shape of nanostructure, so in the end, we compared the lasing behavior of the Sn-doped CdS nanowire with rectangular and hexagonal shaped cross section. As shown in Figure 2f, due to the nonregular shape of the cross section (SEM image shown in the inset of Figure 2f), only two lasing modes are observed, while six lasing modes can be collected at hexagonal cross-sectional Sn-doped CdS nanowires, providing an easy way to realize single-mode lasing.…”

Hyperbranched Microwire Networks of Organic Cocrystals with Optical Waveguiding and Light‐Harvesting Abilities

“…Conceptually, these well‐organized, single‐crystalline hyperbranched MWs may be used as miniaturized optical waveguide elements [10, 45–47] . The photon transport behavior of branching (2:1)10Ft:BA MWs were preliminarily examined by a micro‐PL equipment equipped with a 405 nm continuous wave (CW) laser.…”