Optical bio-chemical sensors based on whispering gallery mode resonators

Abstract

Whispering gallery mode (WGM) resonators have attracted extensive attention and their unique characteristics have led to some remarkable achievements. In particular, when combined with optical sensing technology, the WGM reonator-based sensor offers the advantages of small size, high sensitivity and a real-time dynamic response. At present, this type of sensor is widely applied in the bio-chemical sensing field. In this paper, we briefly review the sensing principle, the structures and the sensing applications of optical bio-chemical sensors based on the WGM resonator, with particular focuses on their sensing properties and their advantages and disadvantages. In addition, the existing problems and future development trends of WGM resonator-based optical bio-chemical sensors are discussed.

Whispering Gallery Mode Optical Microresonators: Structures and Sensing Applications

“…It is easy to coat polymer, nanoparticle, or dye on the surface of the microcavity, which greatly improves the optical sensing performance of the microcavity . Based on the aforementioned, microsphere resonators are particularly suitable for ultra‐high sensitivity research in the fields of physics, biology, and chemistry …”

“…The benefits of this method are a small loss, uniform surface, easy to control the diameter of the microsphere cavity, low cost, and so on. However, the shortcoming is that glass exists in rod form, and only one microsphere cavity can be produced at a time …”

“…[18,19] Based on the aforementioned, microsphere resonators are particularly suitable for ultra-high sensitivity research in the fields of physics, biology, and chemistry. [20]…”

“…However, the shortcoming is that glass exists in rod form, and only one microsphere cavity can be produced at a time. [20][21][22] Hydrogen-oxygen flame method: the top of the fiber is placed in a hydrogen-oxygen/nitrogen-butane microflame for about 1 min, and the fiber head melted into a ball under the action of surface tension. When the tip of the optical fiber melts, the fiber needs to rotate around the axis to minimize the bending of the microcavity.…”

Reflective Fiber Surface Plasmon Resonance Sensor for High-Sensitive Mercury Ion Detection

“…In contrast, fiber optic sensors have unique advantages, such as multiplexing, high flexibility, high sensitivity, remote sensing, low cost, and immunity to electromagnetic interference [9][10][11], which play an increasingly important role in the detection of heavy metal ions. In recent years, researchers proposed many fiber sensing technologies to detect heavy metal ions, including: Evanescent wave absorption [12], Mach-Zehnder interferometer [13], fluorescence [14], and surface plasmon resonance (SPR) [15].…”