03 Jul 2025
Food-safe development by researchers in Ljubljana, Slovenia, could monitor and verify products.
Researchers at the Jožef Stefan Institute in Ljubljana, Slovenia, have demonstrated what they call “edible microlasers” — tiny lasers made entirely from food-safe materials—that can be used for food monitoring, product authentication and tagging.
These edible microlasers are composed of droplets of oil or water–glycerol mixtures doped with natural optical gain substances, such as chlorophyll (the green pigment in leaves) or riboflavin (vitamin B2).
Researchers have shown that olive oil already contains enough chlorophyll to be used directly as a laser in the form of droplets without the need for additional ingredients. They can be excited using external light, such as a pulsed laser. The research is described in Advanced Optical Materials.
Edible microlasers can be realized in different configurations, including whispering gallery modes, in which light circulates inside a droplet, and Fabry–Pérot cavities, in which light reflects back and forth between two surfaces. Their emission properties can be tuned by varying the cavity size or the surrounding conditions, such as the refractive index of the medium.
Due to their highly sensitive output emission, microlasers can serve both as optical barcodes and sensors. For example, researchers have encoded a date into a peach compote using microlaser barcodes embedded inside the food. The barcode remained optically stable and readable for over a year. In other experiments, edible microlasers have been designed to respond to changes in pH, temperature, sugar concentration, and microbial growth, offering a platform for real-time food freshness sensing.
Food-safe
Importantly, according to the researchers, these microlasers do not alter the nutritional value or taste of the food and are suitable for vegetarians. This approach combines photonics and food science in a novel, biocompatible way that could reduce food waste, detect counterfeits, and improve food quality control.
Beyond the food industry, this edible laser technology may also find applications in pharmaceuticals, cosmetics, agriculture, and other fields where biocompatible, ingestible barcodes and sensors are valuable.
Abdur Rehman Anwar, Dr. Maruša Mur, and Dr. Matjaž Humar are physicists working in the Lab for biophotonics, soft photonics and quantum optics at the Jožef Stefan Institute. Anwar, a young researcher, holds a master’s degree from Pakistan, where he worked on LEDs. He is currently focused on developing microlaser-based barcodes and sensors.
Dr. Maruša Mur is a postdoctoral researcher whose PhD research focused on photonic microdevices and topological defects in liquid crystals. Her current work explores bio-integrated photonics and embedding microdevices in biological systems. Dr. Matjaž Humar leads the lab and holds a PhD in optical microresonators. A former postdoctoral fellow at Harvard Medical School, he pioneered intracellular lasers. He is the recipient of two ERC and Marie Skłodowska-Curie Fellowships.