Terahertz Measurements for Ultrafast Dynamics

• Numerous applications call for “ultrafast” terahertz measurements
• High-bandwidth Schottky detectors observe individual terahertz pulses...
• ...at repetition rates as high as 100 MHz
• This enables monitoring of dynamic processes with a sub-µs temporal resolution
• Recommended systems: TeraFlash smart

A range of applications in fundamental science call for terahertz observations at “extreme” speeds. One example involves the study of protein dynamics in water, where solved biomolecules unfold within milli- or microseconds. Spectroscopy under rapidly changing environmental conditions forms yet another active field of research: Pulsed magnets, for instance, generate intense fields which last no longer than a few milliseconds. Time-resolved measurements therefore require truly “ultrafast” methods, with data rates in the kHz to MHz range.

A photoconductive switch hooked up to a femtosecond laser produces tens of millions of terahertz pulses per second. High-bandwith Schottky diodes enable intensity measurements of each individual terahertz pulse. The combination of a powerful InGaAs emitter and a Schottky receiver has been shown to achieve measurement rates up to 100 MHz – orders of magnitude higher than conventional detection schemes based on mechanical delay stages. This enables the observation of dynamic processes with a temporal resolution as short as a ten nanoseconds.