Scientists Successfully Shrink Powerful Femtosecond Laser Onto Single Chip
EPFL researchers achieve 20-year goal of integrating ultrafast laser technology that could revolutionize medical devices and atomic clocks.
Researchers at EPFL have accomplished a breakthrough that has eluded scientists for two decades: successfully shrinking a powerful ultrafast laser onto a photonic chip while maintaining performance comparable to traditional tabletop systems. The integrated device delivers pulse energies of 1.05 nanojoules and pulse durations as short as 147 femtoseconds, representing the first chip-scale ultrafast laser capable of matching conventional femtosecond laser performance. The achievement could dramatically reduce the size and cost of advanced laser technologies used in everything from precision manufacturing to medical diagnostics.
Femtosecond lasers, which produce pulses lasting just quadrillionths of a second, have been among the most powerful tools in modern optics for decades. Their applications span precision eye surgery, manufacturing of microelectronics, and optical frequency combs that power the world's most accurate atomic clocks. Despite their importance, these systems have remained large and expensive, typically occupying entire optical tables and requiring significant infrastructure to operate effectively.
Professor Tobias Kippenberg, who led the EPFL team, noted that creating a high-pulse-energy femtosecond laser on a chip had been widely regarded as the holy grail of integrated photonics for more than twenty years. The researchers achieved this goal using a laser architecture called the Mamyshev oscillator, a design that had received relatively little attention in integrated photonics despite its unique advantages for chip-scale implementation.
The system places a nonlinear waveguide between two optical filters that transmit different portions of the light spectrum. As intense laser pulses travel through the waveguide, they expand into a broader range of colors, allowing part of the broadened pulse to pass through both filters and continue circulating. Weaker light behaves differently, getting blocked by the filters and removed from the cycle. Co-author Zheru Qiu explained that this design is particularly attractive because it requires no components that are difficult to manufacture on silicon nitride chips.
The breakthrough offers significant advantages beyond just miniaturization. Photonic chips confine light to extremely small waveguides, causing strong nonlinear interactions that can destabilize many laser architectures. However, the Mamyshev oscillator proves remarkably resistant to these problems, making it well-suited for integrated photonic devices. The 42-centimeter laser cavity achieved stable operation while maintaining the high performance characteristics needed for demanding applications, potentially opening new possibilities for portable precision instruments and compact quantum technologies.