Tunable optical filter for colorimetric applications

Area of Science:

• Optics
• Materials Science

Background:

• The Christiansen effect describes the phenomenon where the refractive indices of two materials become equal at a specific temperature, leading to increased transmission.
• Traditional filters based on the Christiansen effect often use solid particles, which can limit tunability and performance.

Purpose of the Study:

• To fabricate and characterize a temperature-controlled tunable optical filter utilizing glass fibers instead of solid particles.
• To investigate the transmission properties of this novel filter design within the visible spectrum.

Main Methods:

• Fabrication of a tunable optical filter by substituting solid particles with glass fibers.
• Experimental testing of the filter's performance under controlled temperature conditions.
• Analysis of transmission spectra, including peak wavelength, peak transmission, and full width at half maximum (FWHM).

Main Results:

• The fabricated filter demonstrated temperature-controlled tunability in the visible range.
• At an operating temperature of 95°C, the filter exhibited a peak wavelength of 509.5 nm.
• The filter achieved a peak transmission of 50.8% with a FWHM of 71 nm at 95°C.

Conclusions:

• The use of glass fibers in a Christiansen effect-based filter is feasible and allows for temperature-controlled optical tuning.
• This novel filter design shows potential for applications requiring adjustable optical filtering in the visible spectrum.