Ashish Arora of IISER Pune with the set up. Credit: IISER Pune

A delicate, non-destructive method means scientists can explore a host of quantum processes in extremely thin two-dimensional materials with precision and accuracy1.

This could be used to study a whole range of atomically thin semiconductors, magnets, conductors and insulators, says a team at the Indian Institute of Science Education and Research (IISER) in Pune.

About 100,000 sheets of two-dimensional materials together become as thick as a human hair. At this scale, quantum physics prevails. To better understand quantum materials, the scientists developed a method that employs light excitation and detection.

They used a beam displacer, and a charge-coupled device (CCD) camera integrated into a spectrometer. The beam displacer separated two polarisations of light in space. When polarized light passes through material under a magnetic field, the polarization rotates. Known as the Faraday rotation, this reveals information about the quantum states inside the material.

The spectrometer dispersed light at different wavelengths, while the CCD camera detected these with high precision.

The team, which included Ashish Arora at IISER and Rudolf Bratschitsch and his peers at the University of Muenster in Germany, wrote new mathematical formulae to analyse their data. Previous methods took many hours, but with this method precise measurements can be made within three to four minutes.

The researchers note that it can unveil the properties of 2D materials with high accuracy under very low magnetic fields.