A team led by UC Berkeley has developed a highly sensitive laser detector that produces magnetic resonance images at room temperature using low-power, off-the-shelf magnets.

The apparatus uses polarised laser light to align rubidium atoms in a vapor. The atomic alignment changes in response to faint magnetic signals and the same laser can measure these slight changes, so less powerful magnets are required.

The apparatus could be scaled down to handheld size, the scientists believe.