Light and plasma are central research tools in the natural, engineering, and life sciences, and the foundation for photonic technologies. Tailored light across broad spectral and temporal ranges has massively expanded the application possibilities of photonic methods. It makes photonics one of the most important key and cross-cutting technologies for the 21st century.
Photonic technologies are applied in many fields, including the geo-, space, and life sciences, medicine, communication, quantum technologies, security applications, and data storage. Photonic research and technologies are among the most important innovation drivers for modern society and the economy.
The development of novel light sources and in particular new laser systems benefits many areas of science and technology. These include ultra-stable lasers with narrow linewidths, lasers with ultrashort pulses, and lasers emitting in new spectral ranges. It encompasses a wide variety of technologies, including crystals, semiconductors, fibres, and waveguides on photonic chips.
As a type of laser system, optical frequency combs are being developed across all regions of the electromagnetic spectrum, from the terahertz to the extreme ultraviolet range. Various photonic technologies are employed, from mode-locked lasers based on crystals or doped fibres to passive and active components on photonic chips. They are used for a wide variety of precision measurements and in quantum technology, from the frequency standard and clockwork mechanism for an optical clock to sensors in spectroscopy and length measurements.
The Leibniz institutes of the section work in a field ranging from the fundamental understanding of light-matter interaction on extreme temporal and spatial scales to optoelectronic devices and technical systems. Light-matter interactions are used to investigate materials and components, to shape surfaces and nanostructures, and to switch their properties. A particular potential for applications lies in the coordinated joint design of light and matter, through which entirely new functionalities for applications based on quantum effects can be realised, in direct interplay between photonics and materials research. Theoretical work and mathematical methods of analysis and simulation also play an important role.
In the terahertz range — i.e., in the electromagnetic spectrum at the transition from long-wave infrared radiation to electronic frequencies for wireless communication — fundamental optical and electrical material properties are investigated. Various diode lasers, such as quantum cascade lasers or high-power lasers, as well as novel detectors, are synthesised at the Leibniz institutes with atomic precision, optimised by means of theoretical analyses, and validated using the latest materials characterisation methods. Translated into next-generation devices, the results open up promising applications, for example in security technology at airports, in the exploration of the Earth‘s atmosphere and outer space, and in the development of cost-effective resilience systems for the protection of our public life.
The spectral range of X-ray radiation offers new possibilities for studying the atomic and electronic structure of materials in a time-resolved manner, thereby understanding dynamic processes on the atomic and nanometre scale that — beyond the fundamental gain in knowledge — can in future be used as mechanisms for realising novel applications, e.g. in the field of quantum-based sensing. Films with nanometre resolution allow functional components to be analysed and optimised.
Optical methods can be used in a versatile manner; the Leibniz institutes of the section develop new methods and push the boundaries of what is technically possible. Dual-comb interferometry extends the limits of precision measurement in several areas. As a spectroscopic technique, it provides insight into the structure of matter or serves sensor applications, e.g. for environmental or health diagnostics. Further applications of interferometry include dimensional metrology of macroscopic objects with sub-nanometre accuracy. In the field of astrophysics, photonic methods — so-called astrophotonics — enable new approaches in the miniaturisation of optical elements, in order to gather new insights in space missions and to carry out precision measurements in spectroscopy and interferometry.
In the field of Earth’s atmosphere, the Leibniz institutes develop special procedures for the use of lasers, the so-called “LiDAR” (Light Detection and Ranging). LiDAR is used to investigate the thermal and dynamic structure from the Earth‘s surface to the uppermost layer of the atmosphere, the thermosphere. The systems developed by Leibniz institutes achieve temporal and spatial resolutions that allow new insights into the global interplay of our planet and enable scientific predictions and a global understanding of the benefits of sustainable action on the habitability of our planet. Improved LiDAR systems secure the world-leading technological position in autonomous driving, as they are indispensable for distance measurement.
In parallel, the development of new photonic systems (plasma, light) is being pursued, including for environmental analytics, the exploration of plasma- and ion-assisted technologies for precision manufacturing of surfaces for optics and photonics, through to applications in medical technology, such as in devices for medical diagnostics and new forms of therapy, as well as applications in hygiene. Cold atmospheric pressure plasmas additionally enable novel combinations of photonic and plasma-based processes.
Further important research topics include the development of analytical methods for thin films and smallest material quantities, the development of compact diode lasers with high output power, new applications of plasma and laser technology in medicine, sensing, and process engineering, as well as the monolithic integration of light sources from III–V compound semiconductors into silicon technology. New technological and materials science challenges, such as the integration of optical photonic circuits on the scalable silicon technology platform, are being actively pursued, as is the synthesis and realisation of innovative quantum light sources based on entangled photons for use in medicine and environmental analytics.