We demonstrate a low-threshold microsphere laser on a silicon chip, fabricated from erbium-doped silica sol–gel film. Single-longitudinal mode lasing emission is observed from a 37 μm diameter microsphere cavity with an erbium ion concentration of 2× 1019 cm−3. The measured lasing threshold of the silica microsphere laser is as low as 4.8 μW. (Some figures may appear in colour only in the onlin...

We analyze second order parametric processes in a silica microsphere coated with radially aligned nonlinear optical molecules. In a high-Q nonlinear microsphere, we discover that it is possible to achieve ultralow threshold parametric oscillation that obeys the rule of angular momentum conservation. Based on symmetry considerations, one can also implement parametric processes that naturally gen...

We experimentally demonstrate controlled polarization-selective phenomena in a whispering gallery mode resonator. We observed efficient ( approximately 75%) polarization conversion of light in a silica microsphere coupled to a tapered optical fiber with proper optimization of the polarization of the propagating light. A simple model treating the microsphere as a ring resonator provides a good f...

Spherical silica optical microresonators were doped with erbium ions by ion implantation at energies of 925 keV and 2.05 MeV using a rotating stage. After thermal annealing at 800 C, light was coupled into the microsphere using a tapered optical fiber. An optical quality factor as high as 1.9 · 10 was observed at k = 1450 nm, corresponding to a modal loss of only 0.01 dB/cm. When pumped at 1450...

A silica microsphere suspension and a silica sol are employed in a two-step dipping process for the preparation of a superhydrophobic surface. It's not only a facile way to achieve the lotus effect, but can also create a multi-functional surface with different wetabilities, adhesive forces and transparencies.

We have locked a whispering-gallery resonance of a fused-silica microsphere to a frequency-scanning laser. The resonance frequency is modulated by axial compression of the microsphere, and phase-sensitive detection of the fiber-coupled optical throughput is used for locking. Using a laser wavelength of either 1570 nm or 830 nm, we demonstrate a locked tracking range exceeding 30 GHz for a micro...

Copper nitride nanoparticles supported on a mesoporous superparamagnetic silica microsphere exhibit superior activity toward the Huisgen cycloaddition of azides and alkynes. The nitride catalyst offers significant advantages over homogeneous Cu catalysts.

A novel room‐temperature photodetector based on a silica‐microsphere optical resonator operating from the mid‐infrared to terahertz spectral region is reported. The sensor relies free‐space visible laser whose frequency locked center of whispering‐gallery mode (WGM). devised scheme automatically tracks any small change in microresonator's size and refractive index that occurs upon illumination ...

Doppler cooling the center-of-mass motion of an optically levitated microsphere via the velocity-dependent scattering force from narrow whispering gallery mode resonances is described. Light that is red detuned from the whispering gallery mode resonance can be used to damp the center-of-mass motion in a process analogous to the Doppler cooling of atoms. The scattering force is not limited by sa...