Autocorrelation measurement of an ultra-short optical pulse using an electrically focus-tunable lens

Abstract

In this communication, a novel technique to measure the temporal width of an ultra-short optical pulse using an electrically focus-tunable lens (EFTL) is proposed and implemented (no need for a mechanical translation stage). The principle is based on the time delay experienced by the pulse when it passes through the deformed membrane of the EFTL as the focal length changes by an applied current. The resolution of the system is approximately 0.23 fs, with a total time delay of 0.69 ps. A typical autocorrelation can be performed in less than 5 s with an excellent Signal to Noise Ratio. The same technique can be implemented to study ultrafast phenomena like electronic relaxation or ultrafast fluorescence in a pump-probe configuration.

Integration of liquid crystal optical delay and mechanical stage optical delay for measurement of ultrafast autocorrelations and terahertz pulses

“…Serna et al approached this problem by implementing an electrically-focused tunable lens to measure fine temporal step sizes in ultrafast laser autocorrelations [10]. While this measurement technique is elegant, the actuation that alters the lens focus, includes the compression of a polymer membrane.…”

“…This is advantageous as it has minimal modification to beam parameters (e.g. beam shaping, fiber optic coupling [10,11,15]). Optical techniques integrating LC devices have improved acquisition parameters [16,17].…”