Spectroscopy in a New Light

Schawlow, A. L.

doi:10.1126/science.217.4554.9

Cited by 12 publications

(8 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition to photons, subatomic particles like neutron (25), electron (26,27) and proton (28) were incorporated later to the techniques of spectroscopy. The introduction of laser (20) , atomic fluorescence for volatile hydride forming elements, microwave induced plasmas for wastewater and biological materials, laser produced plasmas for studies on volatilization and aerosol expansion and inductively coupled plasma mass spectroscopy for the analysis of biological and environmental samples.…”

Section: Historical Backgroundmentioning

confidence: 99%

“…As summarized from reviews (20,21) and literature (22)(23)(24), spectroscopy evolved as a technique for studying the structure of atoms and molecules by observing the interactions of only electromagnetic radiation of selective wavelengths with material objects. In addition to photons, subatomic particles like neutron (25), electron (26,27) and proton (28) were incorporated later to the techniques of spectroscopy.…”

Section: Historical Backgroundmentioning

confidence: 99%

See 1 more Smart Citation

Imaging spectroscopy: Origin and future trends

Raychaudhuri

2015

Applied Spectroscopy Reviews

View full text Add to dashboard Cite

Imaging spectroscopy', a useful tool for modern spectroscopic studies can embed both spatial and spectral information to a set of images and derive the spectra from that. Such techniques are implemented to diversified fields like space observation and laboratory studies of solid materials.The present article intends to highlight the less noticed but significant fact that today's imaging spectroscopy in physical science originates from 'hyperspectral remote sensing', a technique for earth science that acquired maturity during the last three decades. It introduces several applications of spectral imaging for terrestrial and extra-terrestrial objects and anticipates some future trends in this technique. Implementation of imaging spectroscopy to atomic and molecular physics is hoped to provide with an indication of future researches in this direction.

show abstract

Section: Historical Backgroundmentioning

confidence: 99%

Section: Historical Backgroundmentioning

confidence: 99%

Imaging spectroscopy: Origin and future trends

Raychaudhuri

2015

Applied Spectroscopy Reviews

View full text Add to dashboard Cite

show abstract

“…Similarly, Müller first imaged single atoms using field ion microscopy . The demonstration of the laser by Maiman and its applications to molecular spectroscopy by Hansch, Schawlow, and others dramatically increased the resolution and sensitivity of molecular probes through the development of spectroscopic methods such as laser-induced fluorescence , and nonlinear resonant multiphoton ionization . The application of supersonic molecular beam techniques enabled preparation of molecules in well-defined velocity and quantum state distributions and, consequently, the studies of their quantum state-specific unimolecular , and bimolecular dynamics .…”

mentioning

confidence: 99%

Single-Molecule Femtochemistry: Molecular Imaging at the Space-Time Limit

Petek

2014

ACS Nano

View full text Add to dashboard Cite

Through a combination of light and electron probes, it may be possible to record single-molecule dynamics with simultaneous sub-Ångstrom spatial and femtosecond temporal resolution. Single-molecule femtochemistry is becoming a realistic prospect through a melding of laser spectroscopy and electron microscopy techniques. The paper by Lee et al. in this issue of ACS Nano takes a significant step toward chemical imaging at the space-time limit of chemical processes. By imaging electroluminescence spectra of single porphyrin molecules with submolecular resolution, the authors extract the implicit femtosecond dynamics of the coupled electron orbital-molecular skeletal motion triggered by a reduction-oxidation scattering process.

show abstract

“…Then additional narrow absorption dips called "cross-over dips" appear. Since, these narrow width dips are sensitive to the broadening by the collisions, they are observable under the condition that the buffer gas pressure is low [92]. Figure 2.10 shows a typical saturated absorption spectrum of the Rb sub-Doppler peaks obtained from the reference cell in the LH.…”

Section: Saturated Absorptionmentioning

confidence: 99%

Ramsey Spectroscopy in a Rubidium Vapor cell and Realization of an Ultra-Stable Atomic Clock

Gharavipour¹

View full text Add to dashboard Cite

Various application fields in industry, telecommunication, navigation and space demand reliable, compact, high-performance frequency standards with a stability level of <1×10−14 at 105s (equivalent to <1ns/day). Thanks to semiconductor technology, optical pumping technique with a laser has opened up new schemes based on laser-microwave double-resonance (DR), such as continuous-wave (CW) and pulsed optical pumping (POP) to operate vapor cell atomic clocks. In this thesis, we demonstrate the performances of a vapor cell Rubidium (Rb) atomic clock operating in a Ramsey-DR (based on POP) scheme in an ambient laboratory using a compact magnetron-type microwave cavity with a volume of only 45 cm3 and a low quality factor of ≈ 150. The Ramsey-DR scheme involves two resonant electromagnetic fields to interrogate the atoms - the optical field to polarize a population of atoms by optical pumping, and the microwave field to drive the ground-state hyperfine clock transition that serves as an atomic frequency reference. The applied optical and microwave pulses are separated in time in the Ramsey-DR scheme; therefore, the light shift (LS) effects can be strongly reduced which results in improving the clock stability. The magnetron-type microwave cavity is designed, developed and built in collaboration with Laboratory of Electro Magnetics and Acoustics (LEMA) at Ecole Polytechnique Fédérale de Lausanne (EPFL)1. A newly homemade vapor cell with a 10 times smaller stem volume compared to the previous contains 87Rb and buffer gases of Argon and Nitrogen. The smaller stem results in reducing the stem temperature coefficient by about one order of magnitude, which has been a limiting factor for the medium- to long-term scales clock stability. Detailed characterizations and performances of the clock signal (Ramsey central fringe) are presented in this study2. We obtain a clock signal with a contrast up to approximately 35% and a linewidth of approximately 160 Hz by optimizing the various parameters involved in the Ramsey-DR scheme. In our smaller cavity, these achievements are not trivial, because of the high requirements on field homogeneity over the entire cell volume are more challenging to meet. In this work, a short-term stability (1 s to 100 s) of 2.4×10-13τ−1/2 is achieved which is comparable to the state-of-the-art results using the CW-DR scheme and/or using the POP scheme with a larger TE011 microwave cavity with a higher quality factor. The LS effect is quantified in our Ramsey-DR Rb atomic clock. In addition, we present a preliminary model based on the CW-DR LS theory and estimate the intensity LS coefficient in the Ramsey-DR scheme. Moreover, a new analytical expression is developed to predict the clock’s short-term stability by considering the optical detection duration in the Ramsey-DR scheme. From this formula, we also estimate the best Ramsey time to improve the short-term stability of the clock. This thesis, in addition, contains a more fundamental investigation on the measurements of the population and coherence relaxation times (T1 and T2, respectively) of the 87Rb "clock transition". This study has been performed in collaboration with the Institute of Physics Belgrade (University of Belgrade)3. These relaxation times are relevant for our Rb atomic clock, since they limit the usable "Ramsey time" in the Ramsey-DR scheme. An experimental method of Optically-Detected Spin-Echo (ODSE), inspired by classical nuclear magnetic resonance spin-echo, is developed to measure the ground-state relaxation times of 87Rb atoms held in our buffer gas vapor cell. The ODSE method enables accessing the intrinsic (T2 (specific for the clock transition) by suppressing the decoherence arising from the inhomogeneity of the C-field across the vapor cell. The measured T2 with the ODSE method is in good agreement with the theoretical prediction. This work has been done at the Laboratoire Temps-Fréquence of University of Neuchâtel, in col- laboration with the EPFL-LEMA for the magnetron-type microwave cavity, Istituto Nazionale di Ricerca Metrologica (INRIM) that provided the Local Oscillator (LO) and Physics Institute of Belgrade University for relaxation times measurements. 1 Within the projects Fonds National Suisse (FNS):"Microwave Cavities for High Performance Double Resonance Atomic Clocks and Sensors" no. 140712 (2012-2015) and "Study of microwave cavities for high performance pulse pumped double resonance atomic clocks" no. 162346 (2015-2018). 2 Within the MClocks project: "Compact and High-Performing Microwave Clocks for Industrial Applications", EMRP (European Metrology Research Programme, Programme of Euramet) project IND55-Mclocks (2013-2016). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. 3 Within the project FNS (SCOPES): "Ramsey spectroscopy in Rb vapor cells and application to atomic clocks" no. 152511 (2014-2018).

show abstract

Spectroscopy in a New Light

Cited by 12 publications

References 51 publications

Imaging spectroscopy: Origin and future trends

Imaging spectroscopy: Origin and future trends

Single-Molecule Femtochemistry: Molecular Imaging at the Space-Time Limit

Ramsey Spectroscopy in a Rubidium Vapor cell and Realization of an Ultra-Stable Atomic Clock

Contact Info

Product

Resources

About