High power, frequency agile comb spectroscopy in the mid-infrared enabled by a continuous-wave optical parametric oscillator

TL;DR

This paper presents a novel mid-infrared frequency comb generation method using an electro-optic comb to pump a continuous-wave optical parametric oscillator, enabling high power, frequency agility, and broad spectral coverage for advanced spectroscopic applications.

Contribution

The authors introduce a new approach combining electro-optic combs with a singly-resonant optical parametric oscillator to produce high-power, broad, and coherent mid-infrared combs with up to 2400 teeth.

Findings

Generated mid-infrared combs with up to 2400 teeth.

Achieved high-resolution methane spectroscopy.

Theoretical analysis suggests combs can span several THz.

Abstract

While mid-infrared optical frequency combs have been widely utilized in areas such as trace gas sensing, chemical kinetics, and combustion science, the relatively low power per comb tooth has limited acquisition times and sensitivities. We have developed a new approach in which an electro-optic frequency comb is utilized to pump a continuous-wave singly-resonant optical parametric oscillator in order to spectrally translate the comb into the mid-infrared. Through the use of electro-optic combs produced via chirped waveforms we have produced mid-infrared combs containing up to 2400 comb teeth. We show that a comb can be generated on the non-resonant idler when the pump modulation is non-synchronous, and we use these combs to perform high resolution spectroscopy on methane. In addition, we describe the underlying theory of this method and demonstrate that phase matching should allow for combs as broad as several THz to be spectrally translated to the mid-infrared. The high power and mutual coherence as well as the relatively low complexity of this approach should allow for broad application in areas such as chemical dynamics, quantum information, and photochemistry.