Mid-wave infrared multispectral imaging with HgCdTe photodetector.

Area of Science:

• Optics and Photonics
• Materials Science
• Infrared Technology

Background:

• Multispectral imaging offers precise material identification by analyzing absorption/reflection spectra.
• Development of mid-wave infrared (MWIR) multispectral imaging systems is currently limited.
• Existing systems often lack the desired spatial and spectral resolution for complex applications.

Purpose of the Study:

• To develop a novel fabrication strategy for pixel-level bandpass filter arrays in the MWIR.
• To integrate these filters onto HgCdTe photodetectors for simultaneous multi-band acquisition.
• To achieve high-performance multispectral imaging in the MWIR region.

Main Methods:

• A two-step lithography technique was employed for filter array fabrication.
• Four mid-infrared filters were precisely arranged in a 2x2 pattern.
• The filter array was integrated onto 640x512 HgCdTe photodetectors with a 15 µm pitch.

Main Results:

• Simultaneous acquisition of multiple MWIR spectral bands was achieved in a single device.
• Excellent performance was demonstrated with a noise equivalent temperature difference (NETD) below 25 mK.
• Reconstructed images effectively differentiated complex structures and resolved fine details.

Conclusions:

• The developed fabrication strategy is effective and scalable for realizing high-performance MWIR multispectral photodetectors.
• This work advances the capabilities of mid-infrared imaging technologies.
• The technology holds promise for various applications requiring detailed spectral information in the MWIR range.