Max Planck spin-off delivers purer laser light for optical measurements

To the point

• Business innovation: VM Photonics GmbH is a spin-off of the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) and Leibniz University Hannover. It offers ultra-precise laser light for optical measurements that is ten times purer and more stable than that of comparable products.
• Experience: Company founders Henning Vahlbruch and Fabian Meylahn have decades of experience in developing laser systems for gravitational-wave detectors.
• Verified advantage: The new laser system outperforms comparable systems in terms of both power and frequency stability. This advantage is maintained even with subsequent amplification to higher laser power.
• Many applications: Potential applications include measuring gravitational waves, monitoring climate change from space, generating squeezed light and searching for dark matter.

From gravitational-wave research to the market

Forty years after their invention, laser systems based on non-planar ring oscillators (NPROs) are among the most important tools for high-precision physics measurements. They provide the stable and pure laser light that – after further amplification and stabilization – enables the measurement of gravitational waves with instruments such as LIGO and Virgo. Their observations have been revolutionizing astronomy since 2015. “Our team at the Max Planck Institute for Gravitational Physics in Hanover and the Institute for Gravitational Physics at Leibniz University Hanover has decades of experience designing, fabricating, and installing some of the world’s most precise laser systems,” explains Fabian Meylahn, VM Photonics GmbH co-founder at the Max Planck Institute. “We came to the conclusion that we could not only manufacture the commercially available NPRO lasers ourselves, but also significantly improve them,” adds Henning Vahlbruch, the company’s co-founder from the university institute. “Our goal was to develop a laser source that delivers more stable and more pure laser light than what is currently available on the market.”

Measurable progress: laser light 10 times more stable

In a recent publication in Review of Scientific Instruments, Vahlbruch and Meylahn have compared the laser source they developed at the AEI with similar commercial systems. To this end, they developed a test bed to measure the fluctuations in the power and frequency of the laser light. This allowed them to compare the laser sources, each with a power of 400 milliwatts and a wavelength of 1064 nanometers, directly with each other.

Even without the internal power stabilization enabled, a feature available in all devices, the new VM Photonics GmbH development significantly outperformed the other tested devices. With power stabilization enabled, the newly developed source’s laser power fluctuations are far below those of other laser systems across the entire examined spectrum, from 10 hertz to several hundred kilohertz – especially in the low-frequency range. The frequency stability of the new laser system –that is, how much the wavelength of the laser light varies – also exceeds that of the other systems tested by a factor of more than 10 across the entire examined range. The VM Photonics GmbH laser offers an additional low-power mode, delivering only 250 milliwatts instead of the usual 400 milliwatts. This further improves frequency stability.

New horizons: applications beyond astrophysics

“This high-precision laser source has a wide range of applications in which it can deliver more accurate results and more precise measurements,” says Benno Willke, co-author of the study and group leader at the institutes. “Potential applications include measuring gravitational waves on Earth and in space, satellite-based gravimetry for monitoring climate change, comparing atomic clocks, searching for dark matter and new elementary particles, and identifying the fingerprints of quantum gravity.”

This article was first published on 20 November by Max Planck Society.