Noise immune cavity enhanced optical heterodyne velocity modulation spectroscopy

Siller, Brian; Porambo, Michael; Mills, Andrew A.; McCall, Benjamin J.

doi:10.1364/oe.19.024822

Cited by 28 publications

(16 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While our previous cavity-enhanced velocity modulation technique studies 7,28,29 showed a discrimination between ions and neutrals in the lock-in detection phase, the ion beam technique is rigorously insensitive to absorbing or dispersing neutrals.…”

Section: Discussionmentioning

confidence: 84%

“…The geometric mean of these two values gives a rest transition frequency of ν 0 = 10859.34392 cm −1 , which is within 8 MHz of the rest frequency of 10859.34418 cm −1 measured with sub-Doppler resolution and frequency comb calibration in a positive column discharge. 29 This accuracy appears to be limited primarily by the asymmetry in the observed lineshapes (the optical frequency comb itself has an accuracy 1 MHz), and so we expect this to be further improved in the future. …”

Section: A Spectroscopic Resultsmentioning

confidence: 98%

“…The Ti:Sapphire laser, optical cavity, locking scheme, 7, 28 and the NICE-OHMS technique 29 have been described previously, so only a brief overview is given here. Two sets of RF sidebands are added by electro optic modulators (EOM).…”

Section: Heterodyne Detectionmentioning

confidence: 99%

“…For each point in our spectrum, the frequency of the Ti:Sapphire laser is determined by measuring the beat frequency between the Ti:Sapphire laser and the nearest comb mode. 28,29 In order to demonstrate the precision of the spectroscopic measurements, several frequency comb calibrated scans are shown in Sec. III A.…”

Section: Frequency Comb Calibrationmentioning

confidence: 99%

See 3 more Smart Citations

Ultra-sensitive high-precision spectroscopy of a fast molecular ion beam

Mills

Siller

Porambo

et al. 2011

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

Direct spectroscopy of a fast molecular ion beam offers many advantages over competing techniques, including the generality of the approach to any molecular ion, the complete elimination of spectral confusion due to neutral molecules, and the mass identification of individual spectral lines. The major challenge is the intrinsic weakness of absorption or dispersion signals resulting from the relatively low number density of ions in the beam. Direct spectroscopy of an ion beam was pioneered by Saykally and co-workers in the late 1980s, but has not been attempted since that time. Here, we present the design and construction of an ion beam spectrometer with several improvements over the Saykally design. The ion beam and its characterization have been improved by adopting recent advances in electrostatic optics, along with a time-of-flight mass spectrometer that can be used simultaneously with optical spectroscopy. As a proof of concept, a noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) setup with a noise equivalent absorption of ∼2 × 10 −11 cm −1 Hz −1/2 has been used to observe several transitions of the Meinel 1-0 band of N + 2 with linewidths of ∼120 MHz. An optical frequency comb has been used for absolute frequency calibration of transition frequencies to within ∼8 MHz. This work represents the first direct spectroscopy of an electronic transition in an ion beam, and also represents a major step toward the development of routine infrared spectroscopy of rotationally cooled molecular ions.

show abstract

Section: Discussionmentioning

confidence: 84%

Section: A Spectroscopic Resultsmentioning

confidence: 98%

Section: Heterodyne Detectionmentioning

confidence: 99%

Section: Frequency Comb Calibrationmentioning

confidence: 99%

See 2 more Smart Citations

Ultra-sensitive high-precision spectroscopy of a fast molecular ion beam

Mills

Siller

Porambo

et al. 2011

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…The central bore, where the plasma discharge occurs, is surrounded by a sheath of flowing liquid nitrogen, which is in turn surrounded by a vacuum jacket to prevent ice from forming on the cell. OHVMS) 20 configuration, as was done by Crabtree et al 17 One such scan, showing strong central Lamb dip features on top of the Doppler profile, is shown in Figure 5. In this experiment, cavity enhancement is combined with 2f demodulation, making detection sensitive to not only velocity modulation but also concentration modulation of the ions of interest.…”

Section: ■ Experimental Sectionmentioning

confidence: 83%

Indirect Rotational Spectroscopy of HCO⁺

et al. 2013

Self Cite

View full text Add to dashboard Cite

Spectroscopy of the ν 1 band of the astrophysically relevant ion HCO + is performed with an optical parametric oscillator calibrated with an optical frequency comb. The sub-MHz accuracy of this technique was confirmed by performing a combination differences analysis with the acquired rovibrational data and comparing the results to known ground-state rotational transitions. A similar combination differences analysis was performed from the same data set to calculate the previously unobserved rotational spectrum of the ν 1 vibrationally excited state with precision sufficient for astronomical detection. Initial results of cavity-enhanced sub-Doppler spectroscopy are also presented and hold promise for further improving the accuracy and precision in the near future.

show abstract