Atomic and Laser Spectroscopy

Corney, Alan

doi:10.1093/acprof:oso/9780199211456.001.0001

Cited by 203 publications

(157 citation statements)

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“…In helium gas line broadening effects due to increased pressure can be explained by classical theory. Both shift and broadening of lines are proportional to the gas density [28] and are adequately explained by repulsive interaction between an excited atom and surrounded atoms [29] using the "impact approximation" [31]. The line widths that are predicted by this theory are shown in Figure 4 together with the observed widths of the 706 nm atomic line recorded in LHe at 4.2 K as a function of the hydrostatic pressures.…”

Section: Methodsmentioning

confidence: 95%

Spectroscopic investigation of liquid helium excited by a corona discharge: evidence for bubbles and “red satellites”

Bonifaci

Aitken

et al. 2009

Eur. Phys. J. Appl. Phys.

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Abstract. The establishment of corona discharges close to a point electrode under both negative and positive high voltage in normal liquid helium (LHe) at 4.2 K is reported. The experiments were carried out at constant temperature and pressures ranging from 0.1-10 MPa. Visible luminescence emitted from the zone close to the tip revealed lines due to excited He atoms and molecules. The molecular luminescence showed hot band emissions with vibrational levels populated up to v = 2. Rotational temperatures of 800 K were estimated showing that the excitations do not thermalise. With increasing pressure the lines shifted to shorter wavelengths and became broader. The magnitude of the increase in width deviated from what is expected from the gas phase and from classical line broadening theory and rather showed similarities to the behavior of bubbles in LHe. The detailed analysis of the rotational line intensity distribution revealed the presence of an additional radiator at the long wavelength side of molecular bands that we tentatively assign to "red satellite" emission. For corona discharges with positive tip polarities both atomic and molecular lines showed "red satellite" bands with much larger intensity than for negative polarity. The origin of the red satellite and the polarity dependence is unclear yet.

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Section: Methodsmentioning

confidence: 95%

Spectroscopic investigation of liquid helium excited by a corona discharge: evidence for bubbles and “red satellites”

Bonifaci

Aitken

et al. 2009

Eur. Phys. J. Appl. Phys.

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“…As the name suggests this effect is even smaller than the fine structure splitting, reduced by the factor ∼ m e /M P ≈ 1/1836 which is the electron to proton mass ratio. As in the case of the fine structure, we can form the sum of the two coupled angular momentum vectors J and I, in this case giving the total atomic angular momentum F The Hamiltonian describing the interaction between the total electronic angular momentum J and the total nuclear angular momentum I is given by [44][45][46][47] 12) where the interaction between J and the magnetic dipole moment and electric quadrupole moment of the nucleus has been included. Higher order terms resulting from interactions with higher order nuclear moments have been neglected in this Hamiltonian because experimental measurements are not sufficiently accurate to assign a non-zero contribution to them.…”

Section: Hyperfine Structurementioning

confidence: 99%

Single-photon atomic cooling

et al. 2007

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Dedicated to my parents, Anne and Neal Price, and to Elizabeth, my lovely bride to be, whose love and support keeps me going each day. AcknowledgmentsFirst, I would like to thank my supervisor, Dr. Mark G. Raizen. Never before have I met an individual with so many wonderful and inspiring ideas.His ability to see directly to the heart of physical problems and identify their fundamental issues is astounding. Whenever the project ran into what seemed to be serious trouble, Mark would give us a multitude of ideas to circumvent it. He has served as an endless source of ideas, inspiration, and motivation (when needed). I could not have asked for a better advisor and am thankful that he allowed me to join the group in the summer of 2003.This brings me to the wonderful group of people that I have had the pleasure of working alongside throughout these years. A particular thanks and acknowledgment goes to Travis Bannerman. He joined the group a little before my qualifier and has worked on this project with me for almost its entire duration. He is an extremely smart individual with keen physical instincts.He worked very hard, contributed many ideas and helped to make the project a success. I have no doubt that he will bring the experiment to the next level successfully and will continue to do great work beyond this lab, in whatever field he chooses. Next, I would like to thank Kirsten Veiring. She originally joined this lab as a Würzburg master student and did excellent work determining "magic wavelengths" for Sodium and Rubidium. Apparently she enjoyed v her time, and the lab's students, so much that she decided to return to do her doctoral work. When she did so, she joined me in the Rubidium experiment and helped to conclude much of the work discussed in this dissertation. She has a real eye for detail and a tremendously bright future.I would also like to thank other students in the lab who have made my time here so enjoyable. Hrishi has been in the lab the entire time I have.We both became the senior students on our respective projects around the same time. He has always been extremely friendly and helpful. On several occasions when I did not have a needed piece of equipment and he did, he gladly loaned it to me so that I could precede. Tongcang Li has tremendous physical intuition and is always up for an entertaining discussion on one topic or another. Whenever I was stressed, he always seemed to know how to help me put thing into perspective. Adam Libson is a great experimentalist that I have gotten to know well over the years through countless lunches together. His love of physics will take him far. David Medellin is fantastic with equations and has helped many people in the lab, including myself, by clarifying derivations.Isaac Chavez began as an undergraduate in our lab and made the transition into graduate student. He is an extremely hard worker from whom I expect great things. Tom Mazur is the newest member of our group and, in addition to being a really nice person, has started his graduate studies strong.Of cou...

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“…Random spin fluctuations and their associated coherences reveal the complete magnetic structure of the atomic 2 S 1/2 ground state, including hyperfine, Zeeman, and nuclear moment effects. Historically, this information is obtained with conventional magnetic resonance techniques (optical pumping and/or radio-frequency excitation) [22][23][24] , which necessarily perturb the spin ensemble away from thermal equilibrium. ), where is the density of atoms, f and β are the transition's oscillator strength and polarizability (β=2 and -1 for D1 and D2, respectively), ν is the laser frequency, and ∆=ν−ν 0 N 0 is the laser detuning from transition center (assumed here to be much larger than pressurebroadened transition width).…”

mentioning

confidence: 99%

Spectroscopy of spontaneous spin noise as a probe of spin dynamics and magnetic resonance

Crooker

Rickel

Balatsky

et al. 2004

Nature

229

296

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The spin correlation function,, has a Fourier transform S(ω) that is proportional to the measured power spectrum of δθ F (t).A typical noise spectrum from rubidium vapor is shown in Fig. 1b, taken with the laser detuned 25 GHz from the D1 transition. The sharp peaks at frequencies Ω=869and 1303 kHz are due to random spin fluctuations which are precessing in the small 1.85G transverse magnetic field, effectively generating spontaneous spin coherences between ground-state Zeeman sublevels. These coherences precess with effective g- atomic ground state into two hyperfine F-levels with total spin and g-factor, where is the free electron g-factor. Thus, the nuclear spin of 2 ≅ J g 85 Rb (I=5/2) and 87 Rb (I=3/2) may be directly measured from spin fluctuations in thermal equilibrium. Noise spectra acquired near the D2 transition show similar peaks (inset, Fig. 1b), which move as expected with magnetic field. The 13 kHz measured width of these noise peaks indicates an effective transverse spin dephasing time ~100µs, much less than the known Rb spin lifetime (~1s), due largely to the transit time of atoms across the ~100 µm laser diameter. The spectral density of the spin noise is small --the 87 Rb peak in Fig. 1b = ∆That the off-resonant laser non-perturbatively probes spin fluctuations is evidenced in Fig. 2 (Fig. 3c,d Finally, we show that fluctuation correlation spectra can reveal detailed information about complex magnetic ground states arising from, e.g., nuclear magnetism and hyperfine interactions. Figure 4a shows the spin noise spectrum in 39 K.With increasing magnetic field, the noise peak broadens and eventually splits into 4 resolvable spin coherences. This is the well-known quadratic Zeeman effect, which originates in the gradual decoupling of the electron and nuclear spin (the hyperfine interaction) by the applied magnetic field. Within each hyperfine level (see Fig. 4b), the 2F+1 Zeeman levels become unequally spaced, resulting in 2F distinct coherences . The photodiode difference current is converted to voltage (transimpedance gain=40V/mA, or ~20V/mWatt of unbalanced laser power at 790 nm) and measured in a spectrum analyzer. Above a few kilohertz, the measured noise floor arises primarily from photon shot noise, which contributes ~175 nV/ Hz of spectrally flat (white) noise at a typical laser power of 200 µW. The photodiodes and amplifier contribute an additional 65 nV/ Hz of uncorrelated white noise. All noise spectral densities are root-mean-square (rms) values, and spectra were typically signal-averaged for 10-20 minutes. The accuracy of measured hyperfine constants and g-factors was imposed by the gauss resolution of the Hall bar magnetic field sensor. Measurement of inter-hyperfine spin coherence (Fig. 4d) was performed with a higher-bandwidth, lower gain amplifier (~0.70 V/mA), and a typical laser power of 3.5 mW. Unless otherwise stated, measurements of rubidium (potassium) vapor were performed with 250 (125) Torr of nitrogen buffer gas, which broadens the linewidth of the D1 and D2 optical tran...

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Atomic and Laser Spectroscopy

Cited by 203 publications

References 0 publications

Spectroscopic investigation of liquid helium excited by a corona discharge: evidence for bubbles and “red satellites”

Spectroscopic investigation of liquid helium excited by a corona discharge: evidence for bubbles and “red satellites”

Single-photon atomic cooling

Spectroscopy of spontaneous spin noise as a probe of spin dynamics and magnetic resonance

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