An international team of scientists has conducted a detailed study of the optical properties of molybdenum oxychloride (MoOCl₂). This unusual material combines seemingly contradictory characteristics and could become the foundation for ultra-thin augmented reality devices, including smart contact lenses and miniature photonic chips.

The study was published in the journal Nano Letters.

An “Optical Chameleon”

Researchers from XPANCEO, the National University of Singapore, and the University of Chemistry and Technology in Prague discovered that MoOCl₂ exhibits extremely high optical anisotropy — its behavior changes dramatically depending on the direction in which light travels through it.

In one direction, the crystal reflects light like a metal, while in another it transmits light like glass. Because of this remarkable property, the material has been informally dubbed an “optical chameleon.”

The researchers also observed a record-breaking ability, among naturally occurring materials, to alter the direction of light waves. In a specific region of the green spectrum, light traveling through the material slows down significantly, while the electromagnetic field becomes greatly enhanced. This opens up new possibilities for highly efficient interactions between light and matter.

Potential Applications

Thanks to its unique properties, MoOCl₂ could be used to create:

  • Ultra-thin polarizers;
  • Nanophotonic devices;
  • Miniature waveguides;
  • Next-generation photonic processors.

Such technologies could eventually enable contact lenses and augmented reality glasses that are thousands of times thinner than a human hair while still being capable of manipulating light at the atomic scale.

“We are searching for materials capable of controlling light at the level of individual atoms so that we can move beyond traditional bulky optical components,” the researchers noted.

In Brief

Scientists have conducted the first detailed study of molybdenum oxychloride (MoOCl₂), a crystal with unique optical properties. Depending on the direction of light propagation, it can either reflect light like a metal or transmit it like glass. The material exhibits record-breaking anisotropy and enhances light–matter interactions. In the future, MoOCl₂ could serve as the basis for ultra-thin AR glasses, smart contact lenses, and photonic microchips.