High Speed Optoelectronics

Conventional two photon microscopy uses photomultiplier tubes which are too slow and too fragile for surgical imaging applications, where speed is critical and surgeons expect to work with the lights on.  We are developing photodetectors that enable high dynamic range imaging while being resilient to background light.  These custom detectors have been made open-source at https://github.com/OpenSiPM/

OpenSiPM detection module featuring integrated transimpedance amplifier, power supply and digital control over USB-C. The impulse response with the integrated 26 MHz low pass filter is shown on the right.

In addition, the high dynamic range enables scanning a large number of points per second at high signal levels without saturation, enabling high speed and low noise simultaneously.  Our group is developing this technology to enable very high speed imaging of large tissue specimens at high SNR.

GaAsP PMT and SiPM imaging at 50 MP/s. The low saturation power of the PMT means that a limited number of photons are divided over a large number of pixels resulting in poor shot noise limited SNR. The SiPM with 20x higher saturation power and lower excess noise can maintain the same as SNR at much higher imaging rates.