Using two optical frequency combs and a photon counter, the experiments open up amazing prospects for carrying out dual-comb spectroscopy in low-light conditions and they pave the way for unique applications of photon-level diagnostics, such as precision spectroscopy of single atoms or particles for essential tests of physics and ultraviolet photochemistry in the Earths environment or from space telescopes.Advancements in Ultraviolet SpectroscopyUltraviolet spectroscopy plays an important role in the research study of electronic shifts in atoms and rovibronic shifts in molecules. These studies are vital for tests of essential physics, quantum-electrodynamics theory, determination of basic constants, accuracy measurements, optical clocks, high-resolution spectroscopy in support of atmospheric chemistry and astrophysics, and strong-field physics.Scientists in the group of Nathalie Picqué have actually now made a significant leap in the field of ultraviolet spectroscopy by successfully executing high-resolution linear-absorption dual-comb spectroscopy in the ultraviolet spectral variety. “Our innovative approach to low-light interferometry conquers the obstacles postured by the low efficiency of nonlinear frequency conversion, and lays a solid foundation for extending dual-comb spectroscopy to even much shorter wavelengths,” comments Bingxin Xu, the post-doctoral scientist who led the experiments.Indeed, an engaging future application is the development of dual-comb spectroscopy at short wavelengths, to allow precise vacuum- and extreme-ultraviolet molecular spectroscopy over broad spectral periods. Nathalie Picqué concludes.The advancement of dual-comb spectroscopy in the brief wavelength variety promises advances in several clinical and technological fields, underscoring the value of this achievement.Reference: “Near-ultraviolet photon-counting dual-comb spectroscopy” by Bingxin Xu, Zaijun Chen, Theodor W. Hänsch and Nathalie Picqué, 6 March 2024, Nature.DOI: 10.1038/ s41586-024-07094-9.
By Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (MBI) April 20, 2024An ultraviolet photon-counting dual-comb spectrometer. Two ultraviolet frequency combs of a little various pulse repeating frequencies are generated at very low light levels by nonlinear frequency conversion of near-infrared combs. One ultraviolet comb passes through a sample. The two weak combs are then superimposed with a beam splitter and discovered by a photon-counting detector. At power levels more than one million times weaker than generally used, the data of the found photons carries the details about the sample with its possibly highly intricate optical spectrum. Credit: T.W. Hänsch (MPI of Quantum Optics) and N. Picqué (MPI of Quantum Optics, Max Born Institute). In a research study recently published in Nature, scientists from limit Born Institute in Berlin, Germany, and the Max-Planck Institute of Quantum Optics in Garching have revealed a new method for deciphering the residential or commercial properties of matter with light, that can at the same time find and specifically measure numerous substances with a high chemical selectivity.Their method interrogates the atoms and particles in the ultraviolet spectral area at very feeble light levels. Using two optical frequency combs and a photon counter, the experiments open up amazing potential customers for performing dual-comb spectroscopy in low-light conditions and they pave the method for novel applications of photon-level diagnostics, such as precision spectroscopy of single atoms or particles for basic tests of physics and ultraviolet photochemistry in the Earths atmosphere or from area telescopes.Advancements in Ultraviolet SpectroscopyUltraviolet spectroscopy plays a vital role in the research study of electronic transitions in atoms and rovibronic transitions in particles. These research studies are necessary for tests of essential physics, quantum-electrodynamics theory, decision of essential constants, precision measurements, optical clocks, high-resolution spectroscopy in assistance of climatic chemistry and astrophysics, and strong-field physics.Scientists in the group of Nathalie Picqué have actually now made a significant leap in the field of ultraviolet spectroscopy by successfully implementing high-resolution linear-absorption dual-comb spectroscopy in the ultraviolet spectral variety. This cutting-edge achievement opens brand-new possibilities for performing experiments under low-light conditions, paving the method for unique applications in different clinical and technological fields.Principles and Challenges of Dual-Comb SpectroscopyDual-comb spectroscopy, an effective strategy for accurate spectroscopy over broad spectral bandwidths, has been mainly used for infrared direct absorption of small particles in the gas phase. It counts on measuring the time-dependent disturbance in between 2 frequency combs with somewhat various repetition frequencies. A frequency comb is a spectrum of equally spaced, phase-coherent laser lines, that imitates a ruler to measure the frequency of light with severe precision. The dual-comb technique does not struggle with the geometric restrictions connected with standard spectrometers, and uses terrific potential for high precision and accuracy.However, dual-comb spectroscopy usually requires intense laser beams, making it less appropriate for circumstances where low light levels are critical. The team has now experimentally showed that dual-comb spectroscopy can be efficiently employed in starved-light conditions, at power levels more than a million times weaker than those generally used.This advancement was achieved utilizing two distinct experimental setups with different kinds of frequency-comb generators. The group established a photon-level interferometer that properly tape-records the statistics of photon counting, showcasing a signal-to-noise ratio at the basic limitation. This achievement highlights the optimum usage of readily available light for experiments, and opens up the prospect of dual-comb spectroscopy in difficult situations where low light levels are essential.Overcoming Technical Challenges and Future ApplicationsThe scientists dealt with the obstacles associated with creating ultraviolet frequency combs and constructing dual-comb interferometers with long coherence times, paving the way for advances in this sought after objective. They exceptionally managed the shared coherence of 2 comb lasers with one femtowatt per comb line, showing an optimal build-up of the counting stats of their interference signal gradually exceeding one hour. “Our ingenious technique to low-light interferometry overcomes the obstacles postured by the low performance of nonlinear frequency conversion, and lays a strong structure for extending dual-comb spectroscopy to even much shorter wavelengths,” remarks Bingxin Xu, the post-doctoral researcher who led the experiments.Indeed, an engaging future application is the advancement of dual-comb spectroscopy at short wavelengths, to make it possible for precise vacuum- and extreme-ultraviolet molecular spectroscopy over broad spectral periods. Currently, broadband extreme-UV spectroscopy is restricted in resolution and precision, and depends on unique instrumentation at specialized centers.” Ultraviolet dual-comb spectroscopy, while a challenging objective, has now end up being a reasonable one as an outcome of our research. Importantly, our results extend the full abilities of dual-comb spectroscopy to low-light conditions, unlocking unique applications in accuracy spectroscopy, biomedical noticing, and ecological atmospheric sounding. On a more personal note, this turning point results from an experiment performed at the Max-Planck Institute of Quantum Optics and finished whereas I had currently taken up my position of director at limit Born Institute. I can not picture a more awesome way to transition to a new institute. MBI will now host our next interesting experiments in this field!” Nathalie Picqué concludes.The development of dual-comb spectroscopy in the brief wavelength range promises advances in several clinical and technological fields, highlighting the importance of this achievement.Reference: “Near-ultraviolet photon-counting dual-comb spectroscopy” by Bingxin Xu, Zaijun Chen, Theodor W. Hänsch and Nathalie Picqué, 6 March 2024, Nature.DOI: 10.1038/ s41586-024-07094-9.