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If you've ever consumed food made with olive oil, there's a good chance you've unknowingly ingested materials capable of producing lasers. Researchers have recently demonstrated 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 in the journal Advanced Optical Materials.

Edible microlasers can be realized in different configurations, including whispering gallery modes (where light circulates inside a droplet) and Fabry–Pérot cavities (where 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.

Importantly, 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.

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