Optical phase locking of two infrared CW lasers separated by 100 THz

TL;DR

This paper demonstrates phase-locking of two widely separated infrared lasers using harmonic generation and beat note detection, creating a mini frequency comb with high output power across multiple wavelengths.

Contribution

It introduces a novel method to phase-lock two IR lasers separated by 100 THz using harmonic generation and beat note feedback, forming a high-power mini frequency comb.

Findings

Achieved phase-locking of two IR lasers separated by 100 THz.

Generated a mini frequency comb with four high-power optical lines.

Output powers exceed those from femtosecond laser sources by three orders of magnitude.

Abstract

We report on phase-locking of two continuous wave infrared laser sources separated by 100 THz emitting around 1029 nm and 1544 nm respectively. Our approach uses three independent harmonic generation processes of the IR laser frequencies in periodically poled MgO: LiNbO3 crystals to generate second and third harmonic of that two IR sources. The beat note between the two independent green radiations generated around 515 nm is used to phase-lock one IR laser to the other, with tunable radio frequency offset. In this way, the whole setup operates as a mini frequency comb (MFC) emitting four intense optical radiations (1544 nm, 1029 nm, 772 nm and 515 nm), with output powers at least 3 orders of magnitude higher than the available power from each mode emitted by femtosecond lasers.