Ultrafast photon counting applied to resonant scanning STED microscopy

Area of Science:

• Microscopy
• Photonics
• Biophysics

Background:

• Super-resolution microscopy techniques like STED microscopy are crucial for biological research.
• Fast resonant scanning in STED microscopy offers potential for reduced photobleaching and faster acquisition.
• Existing systems often face limitations in speed, field of view, or signal quantification.

Purpose of the Study:

• To develop an ultrafast photon counting system for resonant scanning STED microscopy.
• To enhance image quality and reduce photobleaching in STED imaging.
• To enable hardware-based time-gating for continuous wave STED microscopy.

Main Methods:

• Development of an ultrafast photon counting system utilizing a multigiga sample per second analogue-to-digital conversion chip.
• Implementation of a 450 MHz pixel clock enabling 2.2 ns pixel dwell time.
• Integration of hardware-based time-gating with resonant scanning for continuous wave STED microscopy.

Main Results:

• Achieved an unprecedented 450 MHz pixel clock for ultrafast readout.
• Enabled a large field of view (∼50 × 50 μm) with reduced photobleaching.
• Demonstrated superior signal-to-noise ratio and highly linear quantification for enhanced image quality.

Conclusions:

• A frontier photon counting image acquisition system with ultrafast readout has been constructed.
• The system offers excellent counting linearity and flexibility for signal processing.
• This advancement facilitates resonant-scanning continuous wave STED microscopy with online time-gated detection.