200 femtosecond impulse response of a Fabry-Pérot etalon with the spectral ballistic imaging technique

We use the spectral ballistic imaging technique to measure the impulse response of a Fabry-Pérot etalon with less than 0.2 ps temporal resolution. The results show excellent agreement with the theoretical predictions and negligible noise. Comparison to the Kramers-Kronig method along with its limitations is also presented.