4. Characterization techniques and experimental measurements

4.1 Extreme event measurement issues

Since optical skywaves are, by definition, extreme but rare fluctuations in the electromagnetic field, capturing and measuring them represents a real technological challenge. On the one hand, there is the problem of the non-repeatability of these events, and on the other, their ultra-short duration. Indeed, in order to detect ultra-short events whose arrival time is unknown, the detection method must offer both excellent temporal resolution and high recording capacity (high acquisition rate). In other words, we need to be able to resolve rapid variations on the scale of the optical pulse (fs-ps), but also on a larger scale (ns-µs) extending over billions of pulses in order to achieve sufficient sampling.

On the temporal side,...