Ultrafast laser pulses bring diamond-based quantum internet closer to reality
Researchers from Berlin have demonstrated a new method for generating single photons in a diamond-based quantum system
The controlled generation of single photons is an essential element of numerous quantum technology applications, such as quantum networks and quantum computing. A research team from the Integrated Quantum Photonics working group at the Department of Physics at Humboldt-Universität zu Berlin and the Joint Lab Diamond Nanophotonics at the Ferdinand-Braun-Institut (FBH) in Berlin, led by Prof. Dr. Tim Schröder, has now demonstrated the successful application of the new SUPER (Swing-UP of the quantum EmitteR population) method. The approach facilitates the controlled generation of light particles (photons). Results of the study were recently published in the journal Nature Communications.
New SUPER method renders photon generation more efficient
The study focuses on diamond crystals that contain specific defects in their atomic structure – so-called tin vacancy centers (SnV centres), also known as color centers. These atomic structures serve as stable quantum bits (qubits), which can store and process quantum information and couple it to light particles. A major challenge in quantum technology to date has been controlling these qubits with light while simultaneously clearly detecting the photons emitted by the qubits as information carriers. Conventional approaches often rely on complex filtering techniques that reduce efficiency and limit the scalability of the system for practical applications.
Working together with Prof. Doris Reiter and Dr. Thomas Bracht from TU Dortmund University, the research team has now shown that this problem can be solved using the new SUPER method, co-developed by the colleagues in Dortmund. In SUPER, two precisely tuned laser pulses (control lasers) excite the quantum system. This makes it much easier to separate the control laser from the individual photons that carry the quantum information. The researchers controlled the qubits using extremely short laser pulses. These pulses operate in the femtosecond range (one quadrillionth of a second) and represent one of the fastest optical control operations ever demonstrated for diamond-based quantum systems.
Ultrafast laser pulses improve control over the quantum state
‘With ultrafast pulses, we can control the quantum state on completely new time scales. This opens the door to faster and more complex quantum operations in diamond,’ says Cem Güney Torun, doctoral student at the Department of Physics and one of the two lead authors of the study. Mustafa Gökçe, also a lead author and former research assistant at the Department of Physics, adds: ‘Our method enables us to efficiently excite the system while keeping the emitted single photons clean and usable. That is a key requirement for building practical networks for quantum communication.’
Another important finding is that the SUPER method preserves the internal quantum spin state of the system. This property is crucial for generating quantum entanglement between distant nodes, another cornerstone of future quantum communication networks.
Combination of nanofabrication, ultrafast optics, and modelling enables new insights
For the study, the quantum researchers combined various experimental approaches: the fabrication of diamond nanostructures with embedded tin vacancy centers, ultrafast optical technologies, and theoretical modelling. This combination enabled the team to demonstrate that SUPER provides a powerful new tool for solid-state quantum technology. The results bring diamond-based quantum repeaters and distributed quantum computers one step closer to practical application.
Link to the article in Nature Communications: https://www.nature.com/articles/s41467-026-69911-1
Contact:
Humboldt-Universität zu Berlin
Institut für Physik
Working group “Integrated Quantum Photonics”
www.physics.hu-berlin.de/en/iqp
Prof. Dr. Tim Schröder
+49 30 2093-4818
tim.schroeder(at)physik.hu-berlin.de
M.Sc. Cem Güney Torun
+49 30 2093-82142
toruncem(at)physik.hu-berlin.de
Press release FBH & HU Berlin: 16 March 2026