More than 50 years ago, pioneering work led to the measurement of magnetic fields using optical pumping (excitation using a 'pump' pulse) and probing (measuring changes with a probe pulse) of alkali atoms. More recently, highly sensitive optical atomic magnetometers based on superconducting quantum interference devices (SQUIDs) have gained ground, particularly for biomedical applications. However, they are very expensive and complicated to operate, requiring cryogenic temperatures. Advances in conventional magnetometer technologies have replaced simple and inexpensive light sources with lasers. Now, highly sensitive measurement of magnetic fields is possible based on optical techniques applied to high-density alkali metal atoms in a vapour. These advances have opened the door to areas previously accessible only with SQUID-based magnetometers. A training network intends to exploit this with EU support of the COSMA (Coherent optics sensors for medical applications) project. The emerging technology is highly sensitive and already much less expensive than SQUIDs. Innovative compensation of spurious magnetic fields that eliminates the need for expensive isolated rooms will further increase the many benefits. Scientists are exploiting precise laser spectroscopy experiments, complex theoretical calculations and expertise in biomagnetic phenomena. Ten research groups from Armenia, Bulgaria, India, Israel, Italy, Poland, Russia, the United Kingdom and the United States are supporting the training effort. Nine of them have a long and successful history of collaboration. Research on all lines of inquiry is progressing quite well. To date, 23 of the 25 planned exchanges of the first reporting period have been successfully carried out. The teams have advanced their objectives regarding optical atomic magnetometers with stray magnetic field compensation for medical applications. A novel device for measurement of low-field nuclear magnetic resonance is delivering promising results. The teams have already published first results on their novel systems and techniques. COSMA is intended to transfer knowledge among teams and researchers, strengthening existing ties and building new ones while advancing scientific expertise related to detection and analysis of biomagnetism. It appears to have found the formula for success and is on the road to cost-effective and high-sensitivity biomagnetism measurement in a magnetically unshielded environment.
Biomagnetism, magnetic fields, magnetometers, superconducting quantum interference devices, optics sensors