Dynamic measurement for electric field sensor based on wavelength-swept laser

Area of Science:

• Optics and Photonics
• Materials Science
• Electrical Engineering

Background:

• Nematic liquid crystals (NLCs) exhibit electro-optic properties, changing their refractive index under an applied electric field.
• Fabry-Perot etalons are optical resonators sensitive to changes in their optical path length.
• Existing electric field sensors may lack dynamic measurement capabilities or require complex setups.

Purpose of the Study:

• To demonstrate a dynamic measurement technique for electric field sensing.
• To utilize a nematic liquid crystal Fabry-Perot etalon for electric field detection.
• To measure the frequency of dynamic electric field variations.

Main Methods:

• Employing a wavelength-swept laser to probe a nematic liquid crystal Fabry-Perot etalon.
• Measuring the shift in transmitted peak wavelengths as a function of applied electric field strength.
• Analyzing the temporal modulation of transmitted peaks to determine electric field frequencies.

Main Results:

• The effective refractive index of the NLC decreases from 1.67 to 1.51 with increasing electric field intensity.
• Dynamic variations in the electric field were measured using a high-speed wavelength-swept laser.
• The measured frequencies of dynamic variations closely matched the amplitude modulation frequencies of the electric field.

Conclusions:

• A novel dynamic electric field sensor based on NLC Fabry-Perot etalons is successfully demonstrated.
• The sensor effectively measures the frequency of amplitude-modulated electric fields.
• This technique offers a promising approach for real-time electric field monitoring.