Nathalie Picqué is a research group leader at the Max-Planck Institute of Quantum Optics (Garching, Germany). She was previously a tenured research scientist with the Centre National de la Recherche Scientifique (CNRS) at Orsay (France). Her research focuses on exploring new ideas that involve laser frequency combs and on applying these novel concepts to metrology, molecular spectroscopy, holography and chip-scale sensing.
An optical frequency comb is a spectrum of narrow, evenly spaced, laser lines, which is often generated using an ultrashort-pulse mode-locked laser. An interferometer can be formed using two such frequency combs of slightly different line spacing. Without moving parts, dual-comb interferometers outperform state-of-the-art devices in an increasing number of applications including spectroscopy and holography, offering unique features such as frequency measurements, accuracy, precision, speed. The dual-comb interferometer is an interferometer where the time delay between pairs of interfering pulses is automatically scanned. Fundamentally different from any other type of spectrometers, it performs direct frequency measurements, without geometric limitations to resolution. For spectroscopy, ground-breaking consequences are: (i) unique combination of broad spectral span and Doppler-free resolution; (ii) recording speed: compared to conventional Fourier transform spectroscopy, recording times are shortened from seconds to microseconds; (iii) compactness: a high-resolution broadband gas-phase spectrometer on a photonic chip is demonstrated. Moreover, the capabilities of digital holography are augmented to novel optical diagnostics, such as precise dimensional metrology over large distances without interferometric phase ambiguity, or hyperspectral 3-D imaging with high spectral resolution.