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Université de Fribourg

Experimental study of laser-detected magnetic resonance based on atomic alignment

Di Domenico, Gianni ; Bison, Georg ; Groeger, Stephan ; Knowles, Paul E. ; Pazgalev, Anatoly S. ; Rebetez, Martin ; Saudan, Hervé ; Weis, Antoine

In: Physical Review A, 2006, vol. 74, no. 6, p. 063415

We present an experimental study of the spectra produced by optical–radio-frequency double resonance in which resonant linearly polarized laser light is used in the optical pumping and detection processes. We show that the experimental spectra obtained for cesium are in excellent agreement with a very general theoretical model developed in our group [Weis, Bison, and Pazgalev, Phys. Rev. A 74,...

Université de Fribourg

Sensitivity of double-resonance alignment magnetometers

Di Domenico, Gianni ; Saudan, Hervé ; Bison, Georg ; Knowles, Paul E. ; Weis, Antoine

In: Physical Review A, 2007, vol. 76, no. 2, p. 023407

We present an experimental study of the intrinsic magnetometric sensitivity of an optical or rf-frequency double-resonance magnetometer in which linearly polarized laser light is used in the optical pumping and detection processes. We show that a semiempirical model of the magnetometer can be used to describe the magnetic resonance spectra. Then, we present an efficient method to predict the...

Université de Fribourg

A new optical magnetometer for MCG measurements in a low-cost shielding room

Bison, Georg ; Schläpfer, U. ; Di Domenico, Gianni ; Saudan, Hervé ; Weis, Antoine

In: International Congress Series, 2007, vol. 1300, p. 561-564

In the past years we were able to show that room temperature optical magnetometers based on magnetic resonance in atomic vapors can be used to measure magnetocardiographic (MCG) signals of healthy adults. The objective of our ongoing work is to demonstrate that multichannel arrangements of affordable and maintenance-free optical magnetometers can be operated in clinical settings. On the way to...

Université de Fribourg

Laser-pumped cesium magnetometers for high-resolution medical and fundamental research

Groeger, Stephan ; Bison, Georg ; Knowles, Paul E. ; Wynands, Robert ; Weis, Antoine

In: Sensors and Actuators A: Physical, 2006, vol. 129, no. 1-2, p. 1-5

Laser-pumped cesium magnetometers allow highly sensitive magnetometry at room temperature. We report on applications of that technique in biomagnetic diagnostics and in a neutron electric dipole moment (nEDM) experiment. In the biomagnetic application the magnetic field from the beating human heart is detected using a gradiometer, which reaches an intrinsic sensitivity of 80 fT/Hz1/2....

Université de Fribourg

Theory of double resonance magnetometers based on atomic alignment

Weis, Antoine ; Bison, Georg ; Pazgalev, Anatoly S.

In: Physical Review A, 2006, p. 033401

We present a theoretical study of the spectra produced by optical–radio-frequency double resonance devices, in which resonant linearly polarized light is used in the optical pumping and detection processes. We extend previous work by presenting algebraic results which are valid for atomic states with arbitrary angular momenta, arbitrary rf intensities, and arbitrary geometries. The only...

Université de Fribourg

A sound card based multi-channel frequency measurement system

Groeger, Stephan ; Bison, Georg ; Knowles, Paul E. ; Weis, Antoine

In: The European Physical Journal: Applied Physics, 2006, vol. 33, p. 221-224

For physical processes which express themselves as a frequency, for example magnetic field measurements using optically-pumped alkali-vapor magnetometers, the precise extraction of the frequency from the noisy signal is a classical problem. We describe herein a frequency measurement system based on an inexpensive commercially available computer sound card coupled with a software single-tone...

Université de Fribourg

A high-sensitivity laser-pumped Mx magnetometer

Groeger, Stephan ; Bison, Georg ; Schenker, Jean-Luc ; Wynands, Robert ; Weis, Antoine

In: The European Physical Journal D, 2006, vol. 38, no. 2, p. 239-247

We discuss the design and performance of a laser-pumped cesium vapor magnetometer in the Mx configuration. The device will be employed in the control and stabilization of fluctuating magnetic fields and gradients in a new experiment searching for a permanent electric dipole moment of the neutron. We have determined the intrinsic sensitivity of the device to be 15 fT in a 1 Hz...

Université de Fribourg

Development of an optical cardio-magnetometer

Bison, Georg ; Weis, Antoine (Dir.) ; Scheffold, Frank (Codir.) ; Erné, Sergio-Nicola (Codir.)

Thèse de doctorat : Université de Fribourg, 2004 ; Nr. 1450.

This thesis describes the development of a new type of cardiomagnetometer, a device that can measure the magnetic field generated by the beating human heart. Such exceedingly weak magnetic fields carry diagnostically relevant information and can be measured noninvasively at the surface of the body. Cardiomagnetic measurements were previously performed using superconducting magnetometers (SQUID)...

Université de Fribourg

Design and performance of laser-pumpedCs-magnetometers for the planned UCN EDMExperiment at PSI

Groeger, Stephan ; Bison, Georg ; Weis, Antoine

In: Journal of Research of the National Institute of Standards and Technology, 2005, vol. 110, p. 179-183

We designed laser-pumped cesium vapor magnetometers in the Mx configuration for the control and stabilization of magnetic field fluctuations and gradients in a new experiment searching for a permanent electric dipole moment of the neutron. The intrinsic sensitivity of the device was determined to be 30 fT in a measurement bandwidth of 1 Hz, limited by laser noise. In the shot noise...

Université de Fribourg

Optimization and performance of an optical cardiomagnetometer

Bison, Georg ; Wynands, Robert ; Weis, Antoine

In: Journal of the Optical Society of America: B, 2005, vol. 22 No. 1, p. 77-87

Cardiomagnetometry is a growing field of noninvasive medical diagnostics that has triggered a need for affordable high-sensitivity magnetometers. Optical pumping magnetometers (OPMs) are promising candidates for satisfying that need since it has been demonstrated that they can be used to map the magnetic field of the beating human heart. We discuss the principle of a phase-detecting OPM and...