Interferometric carrier-envelope phase stabilization for ultrashort pulses in the mid-infrared

TL;DR

This paper presents a novel active stabilization method for the carrier-envelope phase of mid-infrared pulses generated through difference-frequency mixing, achieving sub-30 mrad phase jitter and enhanced pulse energy stability.

Contribution

The study introduces a new CEP stabilization technique using ellipsometry of overlapping pulses, enabling precise phase control in MIR pulse generation.

Findings

Achieved CEP stabilization with phase jitter below 30 mrad.

Demonstrated stabilization of MIR pulse energy.

Validated the technique through high-harmonic generation in a semiconductor.

Abstract

We demonstrate an active carrier-envelope phase (CEP) stabilization scheme for optical waveforms generated by difference-frequency mixing of two spectrally detuned and phase-correlated pulses. By performing ellipsometry with spectrally overlapping parts of two co-propagating near-infrared generation pulse trains, we stabilize their relative timing to 18 as. Consequently, we can lock the CEP of the generated mid-infrared (MIR) pulses with a remaining phase jitter below 30 mrad. Employing these pulses for high-harmonic generation in a bulk semiconductor validates our technique. This experiment reveals that our method also stabilizes the energy of the MIR pulses, thereby approaching the intrinsic stability of the underlying laser system.