Serial time-encoded amplified microscopy

Time stretch microscopy, also known as serial time-encoded amplified imaging/microscopy or stretched time-encoded amplified imaging/microscopy' (STEAM), is a fast real-time optical imaging method that provides MHz frame rate, ~100 ps shutter speed, and ~30 dB (× 1000) optical image gain. Based on the photonic time stretch technique, STEAM holds world records for shutter speed and frame rate in continuous real-time imaging. STEAM employs the Photonic Time Stretch with internal Raman amplification to realize optical image amplification to circumvent the fundamental trade-off between sensitivity and speed that affects virtually all optical imaging and sensing systems. This method uses a single-pixel photodetector, eliminating the need for the detector array and readout time limitations. Avoiding this problem and featuring the optical image amplification for improvement in sensitivity at high image acquisition rates, STEAM's shutter speed is at least 1000 times faster than the best CCD and CMOS cameras. Its frame rate is 1000 times faster than the fastest CCD cameras and 10–100 times faster than the fastest CMOS cameras.

History

Time stretch microscopy and its application to microfluidics for classification of biological cells was invented at UCLA.

It combines the concept of spectrally encoded illumination with the photonic time stretch, an ultrafast real-time data acquisition technology developed earlier in the same lab to create a femtosecond real-time single-shot digitizer, and a single shot stimulated Raman spectrometer. The first demonstration was a one-dimensional version and later a two-dimensional version. Later, a fast imaging vibrometer was created by extending the system to an interferometric configuration. The technology was then extended to time stretch quantitative phase imaging (TS-QPI) for label free classification of blood cells and combined with artificial intelligence (AI) for classification of cancer cells in blood with over 96% accuracy.