Photon arrival timing with sub-camera exposure time resolution in wide-field time-resolved photon counting imaging

Area of Science:

• Optics and Photonics
• Biophysical Imaging
• Materials Science

Background:

• Accurate measurement of photon arrival times is crucial for advanced imaging techniques.
• Existing methods often face limitations in temporal resolution, especially for fast decaying signals.
• Luminescence-based sensing requires precise timing for applications like concentration measurements.

Purpose of the Study:

• To develop a method for determining photon arrival times with sub-exposure time resolution.
• To leverage image intensifier phosphor decay for enhanced temporal information.
• To enable parallel, high-time-resolution luminescence decay measurements.

Main Methods:

• Utilizing an ultra-fast CMOS camera coupled with a photon counting image intensifier.
• Exploiting the invariant phosphor decay characteristics of the image intensifier screen.
• Developing a mathematical framework to correlate phosphor decay intensities with photon arrival times.

Main Results:

• Achieved time resolution as low as 1% of the camera's exposure time (approx. 40 ns with microsecond exposures).
• Demonstrated that relative phosphor decay intensities in successive frames uniquely determine photon arrival time.
• Validated the capability for parallel measurement of fast luminescence decays across multiple pixels.

Conclusions:

• The developed method offers unprecedented temporal resolution for photon detection.
• This technique is suitable for measuring fast luminescence decays (100 ns to microseconds).
• Potential applications include advanced oxygen and ion concentration imaging.