Laser emission from tapered fiber-based liquid-crystal microsphere for sensing

Area of Science:

• Optics and Photonics
• Materials Science
• Chemical Sensing

Background:

• Whispering gallery mode (WGM) lasers in microspheres are sensitive to environmental changes.
• Tapered fibers offer advantages over traditional rectangular fibers for microsphere laser integration.
• Liquid crystals provide tunable optical properties crucial for sensing applications.

Purpose of the Study:

• To introduce a novel laser emission probe utilizing liquid-crystal microspheres and tapered fibers.
• To investigate the laser characteristics and sensing capabilities of this new system.
• To explore its potential for microenvironmental biosensing.

Main Methods:

• Injecting cholesteric liquid crystal (CLC) into hollow glass microspheres (HGMs).
• Attaching HGMs to the front end of a tapered fiber to create a laser cavity.
• Analyzing laser emission spectra and wavelength shifts in response to organic vapors.

Main Results:

• The tapered fiber suppressed WGM laser emission, favoring a single-mode photonic bandgap (PBG) laser peak.
• The PBG laser peak wavelength shifted in response to increasing concentrations of organic vapors.
• Demonstrated a tunable laser response to chemical stimuli.

Conclusions:

• Tapered fiber-based liquid-crystal microsphere lasers offer a promising platform for sensing.
• The system exhibits sensitivity to organic vapors, enabling concentration-dependent wavelength modification.
• Potential applications include microenvironmental biosensing and chemical detection.