High-sensitivity miniaturized spectrometers using photonic crystal slab filters

Area of Science:

• Spectroscopy
• Optical Engineering
• Materials Science

Background:

• Miniaturized spectrometers offer portability and cost-effectiveness for onsite analysis.
• A key challenge for miniaturized spectrometers is limited sensitivity due to reduced dimensions and component quality.
• This limits their application in low-light-level measurements.

Purpose of the Study:

• To develop a compact spectrometer with significantly improved sensitivity.
• To overcome the sensitivity limitations of conventional miniaturized spectrometers.
• To enable broader deployment in sensitive analytical applications.

Main Methods:

• Integration of photonic crystal slab filters with band-stop characteristics into an image sensor.
• Utilizing a band-stop strategy where detectors read all wavelengths except the band-stop.
• Employing mathematical spectral reconstruction from a single coded image with pre-calibrated responses.

Main Results:

• Achieved a spectral resolution of 1.9 nm.
• Demonstrated over ten times greater sensitivity compared to conventional grating spectrometers in fluorescence spectroscopy.
• The design is compatible with complementary metal-oxide-semiconductor (CMOS) technology for mass production.

Conclusions:

• The developed compact spectrometer offers a substantial improvement in sensitivity.
• The band-stop filter strategy maximizes energy extraction, enhancing detection limits.
• CMOS compatibility ensures low-cost mass production, paving the way for widespread use in sensitive applications.