Infrared hyperspectral imaging using a broadly tunable external cavity quantum cascade laser and microbolometer focal...

Area of Science:

• Spectroscopy
• Optical Engineering
• Chemical Imaging

Background:

• Mid-infrared (MIR) spectroscopy is crucial for chemical identification and characterization.
• Hyperspectral imaging provides spatial and spectral information, enabling detailed sample analysis.
• Limitations in current systems include speed, spectral range, and brightness.

Purpose of the Study:

• To develop and demonstrate a versatile, high-performance mid-infrared hyperspectral imaging system.
• To achieve rapid acquisition of hyperspectral data cubes with high spectral resolution.
• To showcase the system's capability for chemical imaging of various sample types.

Main Methods:

• Integration of a broadly tunable external cavity quantum cascade laser (EC-QCL) with a microbolometer focal plane array (FPA).
• The EC-QCL provided high-brightness illumination across a spectral range of 985 cm⁻¹ to 1075 cm⁻¹ (9.30–10.15 μm).
• Acquisition of hyperspectral data cubes (hypercubes) with 300 wavelengths at 0.3 cm⁻¹ intervals in 12 seconds.

Main Results:

• Demonstrated high spectral resolution chemical imaging of methanol vapor in both static and dynamic conditions.
• Successfully imaged and characterized multi-component liquid and solid samples.
• The system achieved rapid data acquisition with broad spectral coverage and high spectral resolution.

Conclusions:

• The combined EC-QCL and microbolometer FPA system offers a versatile and efficient platform for MIR hyperspectral imaging.
• The system's capabilities are suitable for analyzing diverse chemical species and sample states.
• This technology advances the potential for real-time chemical analysis and material characterization.