High-sensitivity miniature fiber-optic temperature probe based on cholesteric liquid crystal laser emission

Area of Science:

• Photonics and Optical Sensing
• Materials Science
• Nanotechnology

Background:

• Cholesteric liquid crystals (CLCs) possess unique periodic structures enabling resonant microcavity effects.
• CLC-based devices can function as laser sources when doped with gain media.
• Temperature variations induce shifts in the CLC laser wavelength, forming the basis for sensing applications.

Purpose of the Study:

• To develop a highly sensitive temperature detection method using CLC-filled miniature optical fiber probes.
• To investigate the temperature response characteristics of various CLCs.
• To enhance the temperature sensitivity of fiber-optic probes through material combination.

Main Methods:

• Fabrication of miniature optical fiber probes filled with cholesteric liquid crystals.
• Characterization of CLC laser wavelength shifts in response to temperature changes.
• Linear superposition of temperature sensitivities from two distinct CLCs (CLC2 and CLC4) to optimize probe performance.

Main Results:

• The study demonstrated that CLC's periodic structure acts as a resonant microcavity for laser generation.
• Individual CLCs exhibited varying temperature response characteristics, with CLC2 showing 2.77 nm/°C and CLC4 showing -4.64 nm/°C.
• The optimized fiber-optic temperature sensing probe achieved a high sensitivity of 7.41 nm/°C.

Conclusions:

• CLC-filled optical fiber probes offer a promising platform for sensitive temperature detection.
• Linear superposition of CLC sensitivities is an effective strategy for enhancing sensor performance.
• The developed fiber-optic probe exhibits a significant advancement in high-sensitivity temperature sensing capabilities.