Coherent Two-Photon Excitation by Multiple Light Pulses

Teets, Richard E.; Eckstein, J. N.; Hänsch, Theodor W.

doi:10.1103/physrevlett.38.760

Cited by 158 publications

(59 citation statements)

References 8 publications

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“…The two-photon transition rate was resonantly enhanced via available intermediate states using either two different excitation laser frequencies (13) or high-velocity atomic beams (14). High-resolution two-photon spectroscopy using picosecond pulsed light, hence without any appreciable intermediate-state interaction or absolute frequency reference, has been previously demonstrated (15,16).…”

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confidence: 99%

“…However, their work suggests that versatile programmable molecular systems capable of algorithmic assembly into an infinite variety of 2D or three-dimensional (3D) supra-architectures with increasing pattern complexity, shape, molecular diversity, and size could potentially be generated with nucleic acids (10). Although more chemically labile than DNA, natural RNAs offer a richer treasure trove of rigid structural motifs (11)(12)(13)(14) that can be potential modules for supramolecular engineering (15)(16)(17)(18)(19)(20). RNA tectonics (15) refers to the modular character of RNA, which can be decomposed and reassembled to create new RNA nanoscopic architectures.…”

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confidence: 99%

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United Time-Frequency Spectroscopy for Dynamics and Global Structure

Marian

Stowe

Lawall

et al. 2004

Science

265

195

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Ultrashort laser pulses have thus far been used in two distinct modes. In the time domain, the pulses have allowed probing and manipulation of dynamics on a subpicosecond time scale. More recently, phase stabilization has produced optical frequency combs with absolute frequency reference across a broad bandwidth. Here we combine these two applications in a spectroscopic study of rubidium atoms. A wide-bandwidth, phase-stabilized femtosecond laser is used to monitor the real-time dynamic evolution of population transfer. Coherent pulse accumulation and quantum interference effects are observed and well modeled by theory. At the same time, the narrow linewidth of individual comb lines permits a precise and efficient determination of the global energy-level structure, providing a direct connection among the optical, terahertz, and radio-frequency domains. The mechanical action of the optical frequency comb on the atomic sample is explored and controlled, leading to precision spectroscopy with an appreciable reduction in systematic errors.Ultrashort laser pulses have given a remarkably detailed picture of photophysical dynamics. In studies of alkali atoms (1) and diatomics (2) in particular, coherent wave packet motion has been observed and even actively controlled. However, the broad bandwidth of these pulses has prevented a simultaneous high-precision measurement of state energies. At the expense of losing any direct observation or control of coherent dynamics, precision spectroscopy enabled by continuous wave (cw) lasers has been one of the most important fields of modern scientific research, providing the experimental underpinning of quantum mechanics and quantum electrodynamics.This trade-off between the time and frequency domains might seem fundamental, but in fact it results from pulse-to-pulse phase fluctuations in laser operation. The recent introduction of phase-stabilized, widebandwidth frequency combs based on modelocked femtosecond lasers has provided a direct connection between these two domains (3, 4). Many laboratories have constructed frequency combs that establish optical frequency markers directly linked to a microwave or optical standard, covering a variety of spectral intervals. Atomic and molecular structural information can now be probed over a broad spectral range, with vastly improved measurement precision and accuracy enabled by this absolute frequency-based approach (5). One of the direct applications is the development of optical atomic clocks (6-8). To date, however, traditional cw laserbased spectroscopic approaches have been essential to all of these experiments, with frequency combs serving only as reference rulers (9).Here we take advantage of the phasestable femtosecond pulse train to bridge the fields of high-resolution spectroscopy and ultrafast dynamics. This approach of direct frequency comb spectroscopy (DFCS) uses light from a comb of appropriate structure to directly interrogate a multitude of atomic levels and to study time-dependent quantum coherence. DFCS allows time-resol...

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confidence: 99%

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confidence: 99%

United Time-Frequency Spectroscopy for Dynamics and Global Structure

Marian

Stowe

Lawall

et al. 2004

Science

265

195

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“…The principle of excitation with phase-coherent pulses (Baklanov and Chebotaev 1977) is very similar to Ramsey spectroscopy with spatially separated fields (Ramsey 1949). Experimentally, it was already explored in the late 1970s (Teets et al 1977, Eckstein et al 1978 by exciting atomic sodium using dye laser pulses in a resonator. Similar experiments were performed with two delayed pulses in sodium, demonstrating Ramsey-type interference (Salour and Cohen-Tannoudji 1977).…”

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confidence: 99%

Precision Laser Spectroscopy in the Extreme Ultraviolet

Eikema

Ubachs

2011

Handbook of High‐resolution Spectroscopy

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Techniques for the production of short wavelengths in the extreme ultraviolet wavelength range are described, spanning low‐order harmonic generation in the perturbative regime for narrow bandwidth XUV production to the plateau‐regime with the three‐step collisional model for the generation of high harmonics with broadband ultrafast pulses. In addition, the intermediate regime is discussed for pulses of 300 ps duration, as well as the regime of harmonic conversion based on continuous wave lasers aiming at the production of coherent Lyman‐α radiation. Applications of XUV sources in the frequency domain typically rely on the production of XUV‐light from narrowband Fourier‐transform‐limited pulses for recording high‐resolution spectra. Alternatively, harmonically upconverted pulses of ultrashort duration (with inter‐pulse coherence) can be used for spectroscopic studies in the time and frequency domain (such as direct frequency comb spectroscopy techniques). Examples of both approaches for atomic and molecular spectroscopy are discussed at some length. For precision metrology on atomic systems, a focus is put on the Lamb shift determination in the He ground state. In the realm of molecular spectroscopy, predissociation phenomena in the nitrogen molecule are highlighted, with relevance for dissociation processes occurring in the upper layers of the Earth atmosphere. Similar predissociation phenomena in carbon monoxide are also treated in some detail, in this case with relevance for the chemistry in interstellar clouds. Precision XUV spectroscopy of molecular hydrogen is discussed as well, as it relates to the possibility of detecting a variation of the proton–electron mass ratio on a cosmological time scale. In the last section, applications of direct frequency comb spectroscopic techniques at short wavelengths are explained and prospects are given for using these techniques at extreme ultraviolet wavelengths.

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“…The concept of using a coherent pulse train for high-resolution spectroscopy dates back to the 1970s [32,33], but it was only in 2004 that high-quality DFCS results were obtained using the modern generation of phase-stabilized femtosecond frequency combs [19]. These systems exhibit remarkable pulse-to-pulse phase coherence and frequency stabilities better than one part in 10…”

Section: Dfcs and Uv Frequency Combsmentioning

confidence: 99%

Prospects for precision measurements of atomic helium using direct frequency comb spectroscopy

et al. 2007

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Abstract. We analyze several possibilities for precisely measuring electronic transitions in atomic helium by the direct use of phase-stabilized femtosecond frequency combs. Because the comb is self-calibrating and can be shifted into the ultraviolet spectral region via harmonic generation, it offers the prospect of greatly improved accuracy for UV and far-UV transitions. To take advantage of this accuracy an ultracold helium sample is needed. For measurements of the triplet spectrum a magneto-optical trap (MOT) can be used to cool and trap metastable 2 3 S state atoms. We analyze schemes for measuring the two-photon 2 3 S → 4 3 S interval, and for resonant two-photon excitation to high Rydberg states, 2 3 S → 3 3 P → n 3 S, D. We also analyze experiments on the singlet-state spectrum. To accomplish this we propose schemes for producing and trapping ultracold helium in the 1 1 S or 2 1 S state via intercombination transitions. A particularly intriguing scenario is the possibility of measuring the 1 1 S → 2 1 S transition with extremely high accuracy by use of two-photon excitation in a magic wavelength trap that operates identically for both states. We predict a "triple magic wavelength" at 412 nm that could facilitate numerous experiments on trapped helium atoms, because here the polarizabilities of the 1 1 S, 2 1 S and 2 3 S states are all similar, small, and positive.

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Coherent Two-Photon Excitation by Multiple Light Pulses

Cited by 158 publications

References 8 publications

United Time-Frequency Spectroscopy for Dynamics and Global Structure

United Time-Frequency Spectroscopy for Dynamics and Global Structure

Precision Laser Spectroscopy in the Extreme Ultraviolet

Prospects for precision measurements of atomic helium using direct frequency comb spectroscopy

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