Whether used as a decoration on your charcuterie spread, as a quick snack for the peckish photonics luminary, or as a fake eyeball to gross out trick-or-treaters on Halloween night, the value of a grape should not be understated. To expand on the fruit’s roles beyond set dressing and sustenance, researchers from Macquarie University have demonstrated how ordinary supermarket grapes can enhance the performance of quantum sensors, potentially leading to more efficient quantum technologies. Where did these mad researchers get the idea to use grapes in their research? Well, social media of course! Specifically, viral videos showing the interaction between two grapes placed into a microwave side by side. In the videos, the fruits sent sparks flying while generating plasma between each other, not only captivating scientists everywhere but almost assuredly voiding the warranty on everyone’s favorite kitchen appliance as content creators tested this theory themselves in the quest for more views. Other studies had been performed to investigate the electric fields produced from the interaction, but this team decided instead to focus on the magnetic field effects that are crucial for quantum applications. Grapes courtesy of iStock.com/Tim UR, safety glasses courtesy of iStock.com/VikiVector, and atom molecule icon courtesy of iStock.com/designer29. The team used specialized nano-diamonds containing nitrogen-vacancy centers that act as quantum sensors. These defects (one of the many defects giving diamonds their color), behave like tiny magnets that can detect the presence of magnetic fields. The researchers placed their quantum sensor on the tip of a thin glass fiber and positioned it between two grapes. By shining green laser light through the fiber, they could make these atoms glow red. The brightness of this red glow revealed the strength of the microwave field around the grapes. The size and shape of the grapes proved to be crucial to the experiment’s success. The team’s experiments relied on grapes ~27 mm long to concentrate microwave energy at approximately the right frequency of the diamond quantum sensor. Quantum sensing devices traditionally use sapphire for this purpose, but the Macquarie team theorized that water might work even better, though they conceded that it’s less stable and is apt to lose more energy in the process. This made grapes, which are mostly water enclosed in a thin skin, perfect for testing their theory. The researchers are now developing more reliable materials that could harness water’s unique properties, bringing the world closer to more efficient sensing devices as well as possible quantum technology miniaturization. Unfortunately, with this study concluded, the end has come to the grape’s time in the scientific spotlight, at least for now. But that doesn’t mean you shouldn’t feel a little more appreciation for the fruit the next time you peel a bunch of them in a bowl with the aim of scaring the ever-living plasma out of a few kids next Halloween. The research was published in Physical Review Applied (www.doi.org/10.1103/PhysRevApplied.22.064078).