“Pushing the boundaries of the measurable”

Dr. Thomas, can you briefly introduce Menlo Systems GmbH?

Dr. Gabrielle Thomas: With pleasure. Since our foundation in 2001, we have developed into a globally active developer and manufacturer of technologies for precision measurement technology at the highest level. In essence, these are stabilized lasers for generating optical frequency combs for a wide range of applications: from time and frequency metrology, to high-resolution spectroscopy and two-photon fluorescence microscopy, as well as 3D nanoprinting, to LiDAR, or for use in astronomy and space-based metrology. We also focus on applications in quantum technology. Our product portfolio, which we develop, manufacture and sell with over 200 employees, also includes terahertz systems and femtosecond fiber lasers. Many of our employees have a degree in physics or engineering—and a passion for high-precision photonic solutions. We see it as our task to help scientists and our customers in industry through our solutions to keep on pushing the boundaries of what can be measured. So much so that our astro combs are now considered important enablers in the search for exoplanets of distant stars. Extremely low-noise, high-precision measuring instruments are required to detect the signals of orbiting planets based on their spectral signatures.

Your co-founder was awarded the Nobel Prize in Physics in 2005 for optical frequency comb technology. How have optical frequency combs developed since then?

Thomas: Around 25 years have passed since the first demonstration of fully stabilized optical frequency combs. During this time, the technology has developed from very complex and space-consuming systems, which could only be operated with vast background knowledge, to compact, turnkey products. Today, optical frequency combs work at the touch of a button and can be implemented almost at the volume of a shoe box. The first systems filled entire optical tables. Thanks to consistent industrialization, todays frequency combs offer the necessary reliability for use in research laboratories and high-tech industries, can be adapted to specific customer requirements and also be operated without a PhD. The aim is to allow users to concentrate fully on their goals and dreams instead of having to laboriously familiarize themselves with the operation of our systems.

Menlo is on course for internationalization. What role does your collaboration with Thorlabs and Hamamatsu play in that?

Thomas: We are and will remain on course for growth worldwide. Our relationships with Thorlabs and Hamamatsu are very helpful in this respect, as they both provide us with important insights and support in developing the markets in North America and Asia. They also help us to develop and implement our strategic goals, and inspire us with the experience they have already gained on a global level and on a large scale. Incidentally, both companies are not only cooperation partners, but also shareholders—and therefore strategic partners of Menlo. We are united by the goal of making our internationalization sustainable. So far, we are represented in the U.S., China and Japan, and of course in Germany, France, the UK and Austria.

Can you outline the range of applications for these frequency combs, which are also known as optical rulers?

Thomas: One key application is high-precision spectroscopy, for example for analyzing molecular fingerprints with our mid-infrared frequency combs. But they do also play an important role today in optical clocks, chemical sensors and quantum sensor technology. And let’s not forget time distribution and synchronization in large laboratories. The image of an optical ruler fits. When high-frequency waves pass over a comb structure with extremely precise distances between the individual optical “prongs”, their frequency can be determined very accurately. That is exactly what timing and synchronization systems for large-scale facilities such as particle accelerators or geodetic observatories make use of.

Optical frequency combs are based on high-end photonic components. It is obvious that they are in demand in research, but which industries require such high precision?

Thomas: We are registering great interest and increasing demand from the young, nascent quantum industry, which requires high-precision measuring instruments. It is also dependent on reliable, turnkey solutions so that it can concentrate on the actual use of light for its quantum computer platforms, quantum sensors or optical clocks. Traditional measurement technology is also expanding into the nanometer and in part, sub-nanometer range—for example in the semiconductor industry or the production of high-end optics—where it requires extremely precise optical frequency combs.

To what extent do your laser systems for quantum technology differ from systems for other fields of application—but to what extent are they also similar?

Thomas: A good example is the optical clock. The “pendulum” or oscillator of an optical clock is an atomic transition in the visible part of the spectrum. The number of oscillations per second is several orders of magnitude higher than the microwave oscillations of cesium atomic clocks. More oscillations lead to greater time accuracy, allowing us to determine the time more precisely. Implementing such an optical clock, requires low-noise continuous wave and comb light over a wide frequency range, which can be achieved with our ultra-stable reference laser and optical frequency combs. The stabilized continuous wave light is used for spectroscopy of the clock. The optical frequency comb is used to flexibly transfer the stability of the ultra-stable reference to all required wavelengths and to convert the optical oscillations into electronically measurable signals. Although other applications may not require this high level of precision and flexibility, they must however be reliable, compact and easy to use. Ultimately, we can draw on our modular component kit when configuring systems for all types of applications.

Measurements in quantum technologies probably require similarly sensitive, noise-free instruments as those used to detect exoplanets. Are the measurement tasks in the nano- and macrocosm comparable?

Thomas: There are definitely similarities! Noise or systematic errors can make measurements unusable or greatly distort measurement signals. If you want to identify a tiny exoplanet orbiting a distant star from a distance by means of a periodically recurring but very weak signal, you must be able to distinguish this signal from a large variety of other measured signals without any doubt. The situation is similarly complex in quantum technology and optical clocks, where specific wavelengths and stabilities in the order of 10-18 are required. Precision is the key factor in both areas,- but there are also major differences. It is therefore important to understand the problem individually for each measurement task. Our AstroComb operates in the 10 to 25 gigahertz range and delivers a very flat optical spectrum over a very wide wavelength range. In this respect, it differs quite clearly from the solutions that are used for optical clocks, for example.

Menlo was represented at both LASER World of PHOTONICS and World of QUANTUM 2023. Do you already see quantum technologies as a separate market?

Thomas: In 2023, we celebrated the 50 anniversary of LASER World of PHOTONICS. World of QUANTUM is a little behind. But this market is developing rapidly and has now reached a level where we see it as an independent, standalone target market for our solutions. Photonics, and laser technology in particular, provide the key enabling technologies that are needed for the continuous, successful development of this market. The laser and quantum communities belong together and I see us as one fantastic, growing community. Its a pleasure to be a part of it. Thats why Menlo will also be represented at both trade fairs in 2025, because we feel part of both communities and want to contribute to progress in both worlds with our solutions.