Modulation transfer function measurement of microbolometers with small pixel pitch.

Area of Science:

• Optical engineering
• Microbolometer technology
• Image sensor characterization

Background:

• Miniaturized optical systems face Size, Weight, Power, and Cost (SWAP-C) challenges.
• Decreasing pixel pitch in focal plane arrays (FPAs) is crucial for miniaturization.
• Measuring Modulation Transfer Function (MTF) for small pixels presents high cut-off frequency challenges.

Purpose of the Study:

• To adapt and apply an improved interferometric method for MTF measurement in microbolometer FPAs.
• To assess the performance of FPAs with varying small pixel pitches (17, 12, and 8.5 µm).
• To extract key technological parameters of microbolometer pixels.

Main Methods:

• Utilized an enhanced interferometric method based on Lloyd's mirror setup.
• Applied improved test bench and image processing techniques.
• Fitted experimental results with an analytical model.

Main Results:

• Successfully measured MTF for microbolometer FPAs with 17, 12, and 8.5 µm pixel pitches.
• Experimental data provided insights into pixel size and cross-talk.
• The method demonstrated effectiveness for high spatial frequencies.

Conclusions:

• The improved interferometric technique is suitable for characterizing small-pixel microbolometer FPAs.
• Accurate MTF measurement is vital for assessing miniaturized optical system quality.
• The method facilitates the deduction of critical pixel technological parameters.