RESUMO
A Fabry-Perot interferometer displacement sensor is proposed and demonstrated. This sensor is prepared by inserting two ceramic ferrules into a polydimethylsiloxane (PDMS) hose to generate a Fabry-Perot cavity. The cavity is filled with nematic liquid crystals (NLCs), which induce a Vernier effect due to the birefringence of NLCs. The flexible PDMS hose makes the cavity length adjustable. A displacement sensor with sensitivity of â¼2.97 nm/µm and a dynamic range of 0.9 mm at the center wavelength of 1550 nm is experimentally demonstrated.
RESUMO
A novel high-sensitivity Fabry-Perot (FP) interferometer temperature sensor based on liquid crystals (LCs) and the Vernier effect is proposed and demonstrated in this Letter. This sensor is prepared by inserting two cleaved single-mode fibers into a section of a capillary tube to generate an FP cavity. The cavity is filled with LCs, which induces a Vernier effect due to the birefringence of LCs. The refractive indices of the ordinary and extraordinary light have different responses to the temperature changes. As a result, the temperature sensitivity is significantly improved by detecting the peak shifts of a periodic envelope. The experimental results show that the proposed sensor can provide a high-temperature sensitivity of 19.55 nm/°C. This sensor offers key features and advantages of the Fabry-Perot interferometer, including low cost and good fringe visibility. Furthermore, such a sensor probe can meet different requirements of temperature sensing in various application areas by using different kinds of LCs.
RESUMO
The lasing behaviors of dye-doped cholesteric liquid crystal (DDCLC) microshells fabricated with silica-glass-microsphere coated DDCLCs were examined. Lasing characteristics were studied in a carrier medium with different refractive indices. The lasing in spherical cholesteric liquid crystals (CLCs) was attributed to two mechanisms, photonic band-gap (PBG) lasing and whispering-gallery modes (WGMs), which can independently exist by varying the chiral agent concentration and pumping energy. It was also found that DDCLC microshells can function as highly sensitive thermal sensors, with a temperature sensitivity of 0.982 nmâ °C-1 in PBG modes and 0.156 nmâ °C-1 in WGMs.