Highly sensitive and selective detection of nitrite using a fiber optofluidic laser.

Nitrite ion (NO2-) is a common contaminant that can significantly threaten human health and the environment. In this study, we demonstrate a chemical sensing platform to monitor the nitrite concentration using a fiber optofluidic laser (FOFL). An optical fiber, integrated into a microchannel, is used both as an optical micro-cavity and the sensing element.

Large dynamic range dual-mode pH sensors dye-doped ionic liquid fiber optofluidic lasers.

We report a fiber optofluidic laser (FOFL) using an RhB-doped ionic liquid (BmimPF) as the gain medium and explore its application for large dynamic range highly sensitive pH sensing. Due to the high -factor of the FOFL and the unique merits of BmimPF, lasing emission presents a threshold of only 0.61 μJ mm.

Optical fiber optofluidic laser based on surfactant solubilization of rhodamine B gain in an aqueous solution.

We report a whispering gallery mode (WGM)-based fiber optofluidic laser (FOFL), in which rhodamine B (RhB) in an aqueous surfactant solution of sodium dodecylbenzene sulfonate (SDBS) is used as the laser gain medium. Here, the role of SDBS is to scatter the RhB dye molecules to effectively prevent its self-association in the aqueous solution. Therefore, the fluorescence quantum yield of the used RhB dye is improved due to the enhanced solubilization, which results in a low lasing threshold of ∼2.

High sensitivity pH sensing by using a ring resonator laser integrated into a microfluidic chip.

We present a chip-scale integrated pH sensor with high sensitivity by using an optofluidic ring resonator (OFRR) laser. An optical fiber with a high refractive index (RI) is employed both as an optical cavity and the sensing reactor along a microchannel, while disodium fluorescein (DSF) aqueous solution with a low RI is served as the cladding gain medium and fluorescent probes. The pump light is introduced along the fiber axis and guided by the total internal reflection at the fiber/cladding interface.

Versatile Optofluidic Solid-Core/Liquid-Cladding Waveguide Based on Evanescent Wave Excitation.

In this paper, we present the design and operation of a solid-core/liquid-cladding (SL) waveguide excited by an evanescent wave. To do this, an optical fiber is integrated into a microfluidic channel and pumped along the fiber axis, ensuring the cladding solution is excited by the evanescent field of the guided mode at the core/cladding interface. The pump beam is guided by the total internal reflection in the fiber, providing a uniform excitation along the microfluidic channel.

Demonstration of polarization mode selection and coupling efficiency of optofluidic ring resonator lasers.

We demonstrate the polarization mode selection and the dependence of coupling efficiency on polarization state of pump light for an optofluidic ring resonator (OFRR) laser. An optical fiber is chosen to serve as the ring resonator and surrounded by rhodamine 6G dye solution of lower refractive index as the fluidic gain medium. When the ring resonator is pumped by a linearly s-polarized laser, the emitted whispering gallery mode (WGM) lasing is of parallel polarization (TM mode), while p-polarized laser excitation generates a vertically polarized lasing emission (TE mode), both TM and TE mode lasing emission coexist simultaneously if the ring resonator is pumped by the s- and p-mixed polarized light.

Polarization characteristics of Whispering-Gallery-Mode fiber lasers based on evanescent-wave-coupled gain.

The polarization characteristics of Whispering-Gallery-Mode (WGM) fiber lasers based on evanescent-wave-coupled gain are investigated. For the laser gain is excited by side-pumping scheme, it is found that the polarization property of lasing emission is simply dependent on the polarized states of the pump beams. The polarization property of lasing emission depends on the propagating situation of the pump beams in an optical fiber if the laser gain is excited by evanescent-wave pumping scheme, that is, if the pump beams within the fiber are meridional beams, the lasing emission is a transverse electric (TE) wave that forms a special radial polarization emission.