Gradient-index optofluidic waveguide in polydimethylsiloxane.

We demonstrate a gradient-index (GRIN) optofluidic waveguide using polydimethylsiloxane cured with a radial variation of temperature. The waveguide wraps the microfluidic channel and the GRIN profile localizes the light around it, making the device suitable for evanescent sensing applications. The fabricated waveguide shows good light confinement, with a propagation loss of 1.47 dB/cm at a wavelength of 632.8 nm.

Simulation of an erbium-doped chalcogenide micro-disk mid-infrared laser source.

The feasibility of mid-infrared (MIR) lasing in erbium-doped gallium lanthanum sulfide (GLS) micro-disks was examined. Lasing condition at 4.5 µm signal using 800 nm pump source was simulated using rate equations, mode propagation and transfer matrix formulation. Cavity quality (Q) factors of 1.48 × 10(4) and 1.53 × 10(6) were assumed at the pump and signal wavelengths, respectively, based on state-of-the-art chalcogenide micro-disk resonator parameters. With an 80 µm disk diameter and an active erbium concentration of 2.8 × 10(20) cm(-3), lasing was shown to be possible with a maximum slope efficiency of 1.26 × 10(-4) and associated pump threshold of 0.5 mW.