At ETH Zurich, researchers have developed what may be the most powerful ultra-short laser pulses produced by any laser oscillator to date. The pulses last less than one trillionth of a second and have an average power of 550 watts— their peak power output is an incredible 100 megawatts. Just as a point of reference, the energy in these pulses could light up several hundred thousand vacuum cleaners just for an instant. With more than a 50% increase over the previous best, these new laser pulses represent a major leap forward for this technology.
This technological breakthrough will have far-reaching impacts on fields such as processing materials, medical procedures, precision measurements, and even the development of more accurate atomic clocks. The only problem is that such short laser pulses are not so easy to produce since Q-switching or mode-locking is very involved and requires precisely calibrated equipment and control.
The ETH Zurich team used a short-pulsed disk laser, incorporating advanced techniques to stabilize and amplify the light before converting it into powerful pulses. They employed a special setup of mirrors that made the light pass through the disk multiple times, enhancing its energy. To create the ultra-short pulses, the researchers utilized a Semiconductor Saturable Absorber Mirror (SESAM), a technology developed by Ursula Keller, a physics professor at ETH Zurich, over 30 years ago. This approach allowed the team to efficiently generate stable, high-powered pulses without the drawbacks of conventional laser amplifiers.
Lead researcher Moritz Seidel expressed excitement when the laser pulses were finally produced, highlighting the innovation’s success in overcoming previous limitations in pulse generation. The study demonstrates that combining laser oscillators with semiconductor-based mirrors like SESAM can be a viable alternative to amplifiers, offering greater control and precision.
Looking ahead, Keller and her team aim to further shorten these laser pulses, potentially reaching the attosecond (10?¹? seconds) range, which would open new possibilities in optical quantum computing, LASIK eye surgeries, and creating detailed microstructures in various materials. The breakthrough at ETH Zurich marks a significant advance in ultra-short laser technology, promising diverse applications across science and industry.
