Pixelated gradient thickness optical filter for visible light spectroscopy.

Area of Science:

• Optics and Photonics
• Spectroscopy
• Materials Science

Background:

• Traditional spectroscopy often requires bulky and expensive equipment.
• Miniaturization of spectroscopic devices is crucial for portable applications.

Purpose of the Study:

• To propose and evaluate a miniature, low-cost pixelated gradient thickness optical filter for visible spectroscopy.
• To demonstrate the feasibility of using this filter in a compact spectroscopic module.

Main Methods:

• Fabrication of a 2D array of metal-dielectric-metal thin films in Fabry-Pérot configurations with varying cavity thicknesses.
• Wavelength-selective characterization via transmittance measurements across the visible spectrum.
• Performance evaluation using a CMOS image sensor to record output signals under monochromatic illumination.

Main Results:

• Successful reconstruction of target spectra from sensor data.
• Demonstrated wavelength-selective properties of individual filter pixels.
• Validation of the filter's performance as a spectroscopic module.

Conclusions:

• The proposed pixelated gradient thickness optical filter is a viable technology for low-cost, miniature spectroscopy.
• This innovation can significantly expand the use of spectroscopy in everyday handheld devices.