Modulation transfer function and number of equivalent elements for SPRITE detectors.

Area of Science:

• Optoelectronics
• Infrared detection technology
• Semiconductor physics

Background:

• Signal Processing In The Element (SPRITE) detectors are photoconductive HgCdTe devices.
• SPRITE detectors perform time-delay-and-integration within the detector element, eliminating external circuitry.
• Current models often simplify SPRITE detector analysis using low-frequency approximations.

Purpose of the Study:

• Develop spatial frequency-dependent expressions for SPRITE detector modulation transfer function (MTF) and equivalent element number (N(eq)).
• Provide a more accurate analytical framework for SPRITE detector performance.
• Guide the optimization of SPRITE detector design for specific spatial frequency ranges.

Main Methods:

• Utilized a Green's function method to model carrier generation, recombination, and diffusion processes.
• Derived analytical expressions for MTF and N(eq) as functions of spatial frequency.
• Avoided the conventional low-frequency assumption of a square resolution element.

Main Results:

• Introduced novel spatial frequency-dependent expressions for SPRITE detector MTF and N(eq).
• The derived expressions incorporate physical parameters like element length, carrier lifetime, mobility, and operating voltage.
• Demonstrated the applicability of these expressions in designing optimized SPRITE elements.

Conclusions:

• The developed Green's function approach provides a more comprehensive understanding of SPRITE detector performance across spatial frequencies.
• The derived spatial frequency-dependent expressions enable precise optimization of SPRITE detector design.
• This work advances the design and application of HgCdTe-based SPRITE detectors in infrared imaging.