We have tuned the whispering gallery modes of a fused silica microresonator over nearly 1 nm at 800 nm, i.e. over half of a free spectral range or the equivalent of 10 linewidths of the resonator. This has been achieved by a new method based on the stretching of a two-stem microsphere. The devices described below will permit new Cavity-QED experiments with this ultra high finesse optical resona...

In this paper, we describe the synthesis and characterization of a luminomagnetic microspheres with core-shell structures (denoted as Fe3O4@ SiO2 @SiO2-Tb(PABA)3). The luminomagnetic microspheres were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM),...

Microlaser with multiple lasing bands is critical in various applications, such as full-color display, optical communications, and computing. Here, we propose a simple efficient method for homogeneously doping rare earth elements into silica whispering-gallery microcavity. By this method, an Er-Yb co-doped microsphere cavity the highest quality (Q) factor (exceeding 108) among rare-earth-doped ...

The spectral shift response of optical whispering-gallery modes due to the adsorption and desorption of water molecules into a SiO2 nano-coating is investigated. This coating is applied to a silica microsphere and optical-shift measurements are made at a very low humidity level (<10%). The micro-optical coupling system is incorporated into a sealed vacuum chamber for controlled humidity testing...

A micro-optical force sensor concept based on the morphology-dependent shifts of optical modes of dielectric microspheres is investigated. The optical resonances, commonly referred to as the whispering gallery modes (WGM), were excited by evanescently coupling light from a tunable diode laser using a tapered single-mode fiber. A compressive force applied to the sphere induces a change in both t...

Coatings of spherical optical microresonators are widely employed for different applications. Here the effect of the thickness of a homogeneous coating layer on the coupling of light from a tapered fiber to a coated microsphere has been studied. Spherical silica microresonators were coated using a 70SiO(2)- 30HfO(2) glass doped with 0.3 mol% Er(3+) ions. The coupling of a 1480 nm pump laser ins...

Carbon microsphere was successfully synthesized from waste office paper via hydrothermal method and high temperature treatment in nitrogen atmosphere. The process of carbon synthesis fiber using concentrated sulfuric acid studied, the influence H2SO4 concentration reaction time on hydrolysis considered. To investigate mechanism conversion to microsphere, Fourier transform infrared spectrometry ...

We have developed a novel, spectroscopic technique for high-sensitivity, label-free DNA quantification. We demonstrate that an optical resonance (whispering gallery mode) excited in a micron-sized silica sphere can be used to detect and measure nucleic acids. The surface of the silica sphere is chemically modified with oligonucleotides. We show that hybridization to the target DNA leads to a re...

Miniaturized Whispering Gallery Mode (WGM) temperature sensor has great potentials of high resolution and great on-chip integration capability. This study focuses on the development of this kind of sensor based on the shifting wavelength of the optical resonance due to thermal expansion and thermo-optic effects of a silica microsphere. Excellent linear dependence of the wavelength shift versus ...