Levitated Nanosphere Detects Individual Atomic Collisions
The Yale-led study provides a new method for measuring gas pressure by tracking particle perturbations in a laser trap.
Updated on Oct. 23, 2026 in Physics
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Researchers at Yale University have demonstrated a technique to detect individual atomic collisions using a silica nanoparticle levitated by a focused laser beam. This research-stage experiment, recently published in Physical Review Letters, measured how gas molecules perturb the harmonic motion of the 50 nm sphere.
Why it matters
By tracking these tiny collisions, scientists are developing methods to measure gas pressure at extremely low levels. This capability could eventually allow researchers to reconstruct the momentum of neutrinos by doping nanoparticles with radioactive isotopes.
The experiment used 50 nm silica nanospheres trapped in a laser focus, recording collision impulses at seven distinct pressure points. Researchers monitored motion by tracking the phase of backscattered laser light, which detected small perturbations without dislodging the particle.
The players
Yale University
An academic institution in New Haven known for fundamental research in quantum optics and high-energy physics.
Lawrence Berkeley National Laboratory
A Department of Energy research facility that contributed to this study on nanoparticle dynamics.
The details
The silica nanosphere is suspended in a vacuum chamber using optical tweezers—a high-intensity laser beam that creates an electric field gradient to hold microscopic objects in place. As gas molecules hit the nanosphere, they impart small amounts of momentum, causing minute deviations from the sphere's simple harmonic motion. This shift is captured by measuring the phase of the light reflected off the sphere, allowing the team to count individual collision events.
Timeline
2026: The findings were published in Physical Review Letters.
The Tech Race
This work advances the field of precision optomechanics, where researchers compete to measure increasingly minute forces on suspended objects. It serves as a necessary precursor to using levitated particles for high-energy physics experiments involving neutrino detection.
This research is currently in the experimental stage and does not have immediate commercial applications for the public. Future iterations may lead to more sensitive vacuum sensors for industrial or scientific instrumentation.
The takeaway
This technique proves that nanoparticle motion can serve as a sensitive barometer for gas pressure in extreme vacuums. Readers should track upcoming research on isotope doping, which will be the next milestone for using this platform to study neutrino momentum.
Further reading
For more developments in high-precision measurement, visit Physics.
Source note: This article includes information reported by Physics World.
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