Improvements to a Grating-Based Spectral Imaging Microscope and Its Application to Reflectance Analysis of Blue Pen...

Area of Science:

• Optical microscopy
• Spectroscopy
• Image analysis

Background:

• The chromatically resolved optical microscope (CROMoscope) is a grating-based spectral imaging microscope.
• Previous designs suffered from a twisting aberration and manual wavelength adjustment.

Purpose of the Study:

• To describe a modified CROMoscope design with improved performance.
• To evaluate the new design's capabilities in transmission-absorption and reflectance spectral imaging.

Main Methods:

• Modified CROMoscope geometry with a beam splitter to eliminate aberrations.
• Automated wavelength adjustment for reduced analysis time.
• Transmission-absorption and reflectance spectral imaging experiments.

Main Results:

• Successfully removed twisting aberration and automated wavelength adjustment.
• Achieved a spectral bandpass as small as 1.8 nm.
• Demonstrated high linearity (R² = 0.9999995) and repeatability in wavelength measurements.
• Successfully applied reflectance spectral imaging to classify blue ink samples with 97.6% accuracy using linear discriminant analysis.

Conclusions:

• The modified CROMoscope offers enhanced performance and new capabilities, including reflectance spectral imaging.
• The improved design is suitable for detailed spectral analysis and material classification.