Rubidium Stabilises Laser For Quantum Technology

Researchers at UC Santa Barbara have engineered compact, low-cost lasers matching lab-grade performance, unlocking potential in quantum applications and environmental sensing.

Researchers at the University of California (UC), Santa Barbara, have invented a compact laser capable of delivering lab-grade precision at a fraction of the size and cost. Developed using rubidium atoms and chip-scale integration, this innovation shows immense potential for applications in quantum computing, precision timekeeping, and environmental sensing, including satellite-based gravitational mapping.

Achieving ultra-precise atomic measurements often requires lasers with exceptional spectral purity—light that oscillates at a single, stable frequency. Traditionally, such precision demands bulky and expensive tabletop laser systems. The new device, designed in the lab of Daniel Blumenthal, professor, UC shrinks this capability into a matchbox-sized laser that retains high performance, making it suitable for portable and space-deployable quantum technologies. Researchers believe this development will appeal to scientists working in quantum experiments, environmental monitoring agencies, and space researchers, thanks to its compact design and affordability.

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“These smaller lasers will enable scalable solutions for real-world quantum systems,” explained Andrei Isichenko, a graduate researcher on the project. “They are vital for cold atom quantum sensors and quantum computing with neutral atoms and trapped ions.”

At the heart of the innovation lies rubidium, a well-known element in atomic physics. By stabilising the laser with rubidium’s optical properties, researchers achieved unparalleled precision. “By locking the laser to the atomic transition line, it takes on the stability of that transition,” Blumenthal stated. Unlike traditional systems that rely on multiple components to remove noise, this laser integrates all functions on a single chip.

The team achieved this breakthrough using advanced silicon nitride resonators and low-loss waveguides. Their design not only rivals but outperforms traditional bulky systems in key metrics such as frequency noise and linewidth by four orders of magnitude.

Beyond its precision, the laser offers significant scalability. It employs a USD $50 diode and leverages a cost-effective fabrication process inspired by electronic chip manufacturing. This development opens doors to numerous applications, including atomic timekeeping, earthquake monitoring, and mapping gravitational fields from space.

“The compactness, low cost, and power efficiency make this technology ideal for deployment in space,” Blumenthal noted, highlighting its potential to revolutionise environmental sensing and quantum experimentation.