Real-Time Dynamic Atomic Spectroscopy Using Electro-Optic Frequency Combs

Abstract

3. The right to use all or part of the Article, including the APS-prepared version without revision or modification, on the author(s)' web home page or employer's website and to make copies of all or part of the Article, including the APS-prepared version without revision or modification, for the author(s)' and/or the employer's use for educational or research purposes." November 2016Real-Time Dynamic Atomic Spectroscopy Using Electro-Optic Frequency Combs Spectroscopy is a key technology for both fundamental and applied science. A long-held desire has been the development of a means to continuously acquire broadband spectral data with simultaneous high time and frequency resolution. Frequency-comb technology can open this door: here, we use a spectroscopic technique based on an electro-optic comb to make continuous observations of cesium vapor across a 3.2-GHz spectral bandwidth with a 2-μs time resolution and with 10-MHz frequency sampling. We use a rapidly switched pump laser to burn narrow features into the spectral line and study the response to this step perturbation. This examination allows us to see a number of unexpected effects, including the temporal evolution of the bandwidth, the amplitude, and the frequency of these burnt features. We also report on the previously unobserved effect of radiation reabsorption, which slowly produces a broad pedestal of perturbation around each feature. We present models that can explain these dynamical effects.

Coherent multi-heterodyne spectroscopy using acousto-optic frequency combs

“…Finally, unlike previous approaches that involve non-linear optics phenomena or fast electronics to broaden the spectra, our approach permits the generation of combs with > 1500 coherent lines, and this without adding to the system hardware and/or software complexity. The high spectral resolution of acousto-optic FCs (sub-MHz), combined with the large number of spectral lines, makes them suitable for optical fiber sensing [29] or real-time atomic spectroscopy [30].…”

“…In this paper, we uncover the potentiality of acousto-optic FCs for multi-heterodyne spectroscopy with high spectral resolution. In a first set of experiments, we demonstrate self-heterodyne interferometry [28,30] for measuring the transmission peaks of a Fabry-Pérot cavity with a sub-MHz resolution. Then, by extending the tooth spacing to tens of MHz, we report molecular spectroscopy on the sub-millisecond time scale, albeit at the expense of using a detector with a relatively large RF bandwidth (broader than the measured absorption line).…”

Electromagnetically induced transparency in vacuum and buffer gas potassium cells probed via electro-optic frequency combs

“…Due to their flexibility, agility, and low phase noise electro-optic frequency combs [1–3] have seen widespread adoption for numerous applications including measurements of atomic (e.g., [4–6]) and molecular transitions (e.g., [7–9]), astronomical calibrations [10], and for frequency metrology [11]. As their comb tooth spacing is controlled via the driving radiofrequency waveform, rather than a physical length dimension as for mode-locked lasers, combs with ultranarrow tooth spacings (≪1 MHz) can readily be produced.…”

Quantitative modeling of complex molecular response in coherent cavity-enhanced dual-comb spectroscopy

“…Optical frequency combs (OFCs) [1][2][3][4] enable increasingly precise applications of atomic and molecular spectroscopy [5], including primary thermometry [6,7], optical radiocarbon dating [8], sub-Doppler and Doppler-free spectroscopy [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26], ultrafast and multidimensional spectroscopy [27][28][29][30], survey spectroscopy of molecular ions and cold molecules [31][32][33], and time-resolved spectroscopy for fundamental chemical kinetics [34][35][36][37]. Applied spectroscopies [38] also make novel use of optical frequency combs for actively monitoring greenhouse gas fluxes [39][40][41], methane for open-path detection [42] and unambiguous source attribution [43] and reactive atmospheric species [44], elucidating the chemical composition of combustion and open flames…”