Versatile hybrid plasmonic microfiber knot resonator

Abstract

A planar, all-optical fiber polarizer-based device based on a hybrid plasmonic microfiber knot resonator (HPMKR) is demonstrated in this Letter. A microfiber knot resonator (MKR) can be flexibly attached to the gold film, which forms the hybrid plasmonic mode with high propagation loss. Therefore, the device can be used not only as a broadband polarizer, but also as a high-quality resonator by tuning the geometry of the MKR. The polarizer has an extinction ratio of more than 15 dB ranging from 1200 to 1600 nm, and the Q-factor is more than 52,000 for one polarization state. For a chosen polarization, the resonator has an extinction ratio of nearly 15 dB, even though the diameter of the microfiber is more than 5 μm, which is unattainable for a normal MKR. By further optimizing and packaging, the device can be utilized as a weight sensor, with a sensitivity of 18.28 pm/g (51.2 pm/kPa) for the cavity resonant wavelength. Further, a vibration sensor on a HPMKR structure for detecting vibration from tens of hertz to several kilohertz is demonstrated.

Sensitive and Wearable Optical Microfiber Sensor for Human Health Monitoring

“…[14] From Figure 3a, the resonant wavelength exhibits an obvious blue-shift while we increase the loaded weight from 0 to 50 g. The contact area was 4 mm × 7 mm. In our experiment, the temperature change was less than 2 °C, resulting in a total shift that could not be read out by an optical spectrum analyzer (OSA) (resolution 0.02 nm).…”

“…[13] In addition, there are several microfiber-based resonators [14] applying evanescent-field coupling, which can enhance lightenvironment interaction. An intuitive approach is to employ thin microfibers which allow for large evanescent fields, extreme flexibility, and configurability.…”

“…[14] The flexible HPMKR is composed of a microfiber knot resonator (MKR) situated on a smooth gold film, exciting Silica-fiber-based sensors have the advantage of being small, electrically isolated, immune to electromagnetic fields, and easily incorporated into networks. [14] The flexible HPMKR is composed of a microfiber knot resonator (MKR) situated on a smooth gold film, exciting Silica-fiber-based sensors have the advantage of being small, electrically isolated, immune to electromagnetic fields, and easily incorporated into networks.…”

“…[14] The resonant wavelength shift results in the output light power change of a HPMKR for a certain light-wavelength input. [14] The resonant wavelength shift results in the output light power change of a HPMKR for a certain light-wavelength input.…”

“…[14] The resonant wavelength shift results in the output light power change of a HPMKR for a certain light-wavelength input. [14,18] And the encapsulated PDMS benefits for robustness and biocompatibility of devices. More specifically, the MKR is a miniaturized optical resonator.…”