Low-cost THz electro-optic detection in single-shot and at MHz acquisition rates, using photonic time-stretch

A range of applications requires THz pulses to be recorded in one shot, and at high acquisition rates. This concerns TDS of rapidly evolving samples, and diagnostics in accelerator-based light sources (synchrotron radiation facilities and free-electron lasers). Although demonstrations of MHz+ single-shot TDS have been made, the application range remained very limited because of the high cost of the equipments needed for the readout (typically oscilloscopes with 8-20 GHz bandwidth). We present here the design of a single-shot time-stretch THz digitizer (or time-domain spectrometer), that uses mid-IR laser probes. As a result, low-bandwidth readout oscilloscopes can be now used (down to 1GHz). We present the performances of this novel TDS versus the state-of-art. The new design is expected to extend considerably the application rage of high repetition rate single-shot THz recorders in accelerator physics, and in TDS spectroscopy.