Ultrafast electrooptic dual-comb interferometry.

Vicente Durán,Victor Torres-Company,Santiago Tainta

doi:10.1364/oe.23.030557

Abstract

Dual-comb interferometry is a particularly compelling technique that relies on the phase coherence of two laser frequency combs for measuring broadband complex spectra. This method is rapidly advancing the field of optical spectroscopy and empowering new applications, from nonlinear microscopy to laser ranging. Up to now, most dual-comb interferometers were based on modelocked lasers, whose repetition rates have restricted the measurement speed to ~kHz. Here we demonstrate a dual-comb interferometer that is based on electrooptic frequency combs and measures consecutive complex spectra at an ultra-high refresh rate of 25 MHz. These results pave the way for novel scientific and metrology applications of frequency comb generators beyond the realm of molecular spectroscopy, where the measurement of ultrabroadband waveforms is of paramount relevance.

Highlights

The dual-comb spectrometer is an instrument that unlocks the full potential of laser frequency combs for high-precision spectroscopy [1,2,3,4,5,6]
This choice allows for using low bandwidth detectors (~100 MHz) with high dynamic range (~16 bits), but it comes at the expense of a limit in the refresh rate
We have demonstrated that the electrooptic dual-comb technique allows measuring broadband optical waveforms at ultra-high single-interferogram refresh rates

Summary

Introduction

The dual-comb spectrometer ( known as dual-comb interferometer) is an instrument that unlocks the full potential of laser frequency combs for high-precision spectroscopy [1,2,3,4,5,6]. It offers a spectral resolution capable to resolve the individual frequency components of the comb It can scan terahertz bandwidth spectra at high signal-to-noise ratio (SNR) in relatively fast acquisition times (from milliseconds to a few seconds) because it is free from mechanical moving parts [3]. An additional characteristic of a dual-comb spectrometer is that it can retrieve the spectral phase of the sample under test This has triggered applications different than molecular spectroscopy, such as coherent LIDAR [14,15,16], vibrometry [17] or the analysis of optical telecommunication components [18]

Methods

Discussion

Conclusion