Electrically tuned whispering gallery modes microresonator based on microstructured optical fibers infiltrated with dual-frequency liquid crystals

Abstract

An electrically tunable whispering gallery mode (WGM) microresonator based on an HF-etched microstructured optical fiber (MOF) infiltrated with dual-frequency liquid crystals (DFLCs) is proposed and experimentally demonstrated for the investigation of the crossover frequency and Freedericksz transition of DFLCs. Experimental results indicate that for applied electric field with operation frequency below the crossover frequency, WGM resonance wavelength decreases with the increment of applied electric field strength. On the contrary, for applied electric field with operation frequency beyond the crossover frequency, WGM resonance dips show red shift as the applied electric field intensity increases. The proposed electrically tunable microcavity integrated with DFLCs is anticipated to find potential applications in optical filtering, all-optical switching, and electrically manipulated bi-directional micro-optics devices.

Electrically Tunable Polymer Whispering-Gallery-Mode Laser

“…Under the electric field of 0.48 kV/mm, the maximum blueshift of the first microring laser reaches 0.73 nm, which is in consistency with the second microring laser (0.71 nm). Although the tuning range of this in situ tunable microring laser is limited compared to some tunable WGM lasers with special gain materials [ 26 , 32 , 33 , 37 ] and mechanically tuned WGM lasers in three-dimensional space [ 30 , 31 ], it is ten times that of other WGM lasers tuned in two-dimensional space [ 29 , 34 , 37 ]. Wavelength tuning at different electric field amplitudes is clearly shown in Figure 4 .…”

“…In addition, some researchers have shown that electronically tunable distributed feedback (DFB) lasers can be achieved through electroactive dielectric elastomer actuators [ 35 ] and III–V InGaAsP tuning layers [ 36 ]. To date, there have been a few studies on WGM electrical tuning; microstructural fibers based on dual-frequency liquid crystal (DFLCs) [ 37 ] and metal-dielectric core–shell hybrid microcavities with thermo-optical effects [ 38 ] provide WGM tuning schemes for wavelength shifting by applied electric fields.…”

Metal–Organic Framework Coated Devices for Gas Sensing

“…The sensing principles of MOF-based sensing devices rely on signal transduction stemming from the surface reaction and/or interaction between gas molecules and the sensing materials. ,,, The targeted analyte-MOF interactions cause changes in the physical properties of the sensing materials, and these changes can be detected by the transducer and translated into one or more measurable. Noteworthily, the interactions between the targeted analyte and materials typically involve noncovalent interactions , (e.g., van der Waals forces, hydrogen bonding, and π–π interactions) and covalent bonding, , which are mainly determined by the detected gas molecules and the structure and composition of the sensing material.…”

“…57 Compared with the commonly utilized sensing materials (e.g., polymers, metal oxide semiconductors (MOSs), carbon-based materials, and MXenes), MOFs featuring the merits of high porosity, large specific surface area, controllable pore size/geometry, potential functionalities, and tailor-made physicochemical properties, have been regarded as excellent sensing materials for targeted gas detection. Recently, great advances in the shaping of MOFs onto versatile substrates as functional films have laid the foundation for the preparation of MOF-based sensing devices including MOF-based chemiresistive sensors, 58 capacitors, 59 FETs, 60 electrochemical sensors, 61 QCMs, 62 microresonators, 63 and surface acoustic waves (SAWs). 64 MOF coatings serve as either the sensing layers or molecule-sieving layers outside the active MOS structures.…”

Liquid-Crystal-Filled Side-hole Fiber for High-Sensitivity Temperature and Electric Field Measurement

“…The latest research progress on novel liquid crystal functional materials [12,13,14,15,16] makes it promising to be used in many fields such as smart textiles, energy-efficient electronics, and smart laser protection [17]. Liquid crystals have some unique physical properties, such as good fluidity at normal temperature, under the action of an external electric field, the direction of the liquid crystal molecules rearrange, resulting in a change in the refractive index of the liquid crystal, making it possible to design a liquid-crystal-based fiber electro-optic device by integration of liquid crystal material with optical fiber [18,19,20,21,22].…”