NMR detection with an atomic magnetometer

We demonstrate detection of NMR signals using a non-cryogenic atomic magnetometer and describe several novel applications of this technique. A water free induction decay (FID) signal in a 0.5 $\mu$T field is detected using a spin-exchange-relaxation-free K magnetometer and the possibility of using a multi-channel magnetometer for 3-D MRI requiring only a single FID signal is described. We also demonstrate detection of less than $10^{13}$ $^{129}$Xe atoms whose NMR signal is enhanced by a factor of 540 due to Fermi-contact interaction with K atoms. This technique allows detection of less than $10^{9}$ $^{129}$Xe spins in a flowing system suitable for remote NMR applications

Ab initio oscillator strengths for transitions between J=1 odd and J=1,2 even excited states of Ne I

Ab initio theory is developed for radiative transitions between excited states of neon. Calculations of energies for even excited states J=1, J=2 supplement our previous calculations for J=1 odd excited states. Line strengths for transitions between J=1 odd and J=1,2 even states of Ne I are evaluated. A comparison with experiments and semiempirical calculations is given.Comment: 5 page

Non-linear amplification of small spin precession using long range dipolar interactions

In measurements of small signals using spin precession the precession angle usually grows linearly in time. We show that non-linear interactions between particles can lead to an exponentially growing spin precession angle, resulting in an amplification of small signals and raising them above the noise level of a detection system. We demonstrate amplification by a factor of greater than 8 of a spin precession signal due to a small magnetic field gradient in a spherical cell filled with hyperpolarized liquid $^{129}$Xe. This technique can improve the sensitivity in many measurements that are limited by the noise of the detection system, rather then the fundamental spin-projection noise.Comment: 4 pages, 4 figure