A team of researchers of the Cluster of Excellence “Nanosystems Initiative Munich” (NIM) at the Institute of Physics at Augsburg University and the Walter Schottky Institute at TU Munich successfully used nanomechanical sound waves to control a ‘molecule of light’ formed by two neighboring nanophotonic resonators. In their recent publication in Nature Communications the team led by NIM-Professor Hubert Krenner showed that the vibrating sound wave switches on and off the bond of their photonic molecule at unprecedented speeds.
For their experiments NIM-graduate student Stephan Kapfinger and his supervisor Hubert Krenner at the chair of Experimental Physics I (Prof. Achim Wixforth) at Augsburg University used nanometer-thin membranes of semiconducting material into which they drilled a large periodic array of tiny holes using cleanroom nanofabrication.
In such a structure, a ‘photonic crystal’, light of well-defined energy (or color) can be trapped inside a region where three holes are skipped, thus forming a tiny ‘defect’ and acting as a nanocavity. Together with the group of Dr. Michael Kaniber and Prof. Jonathan Finley at TUM, they designed and fabricated a structure of two adjacent nanocavities, in which photons, single quanta of light, can oscillate back and forth.
“In our photonic molecule, photons behave just like electrons, which create a chemical bond in a hydrogen molecule. While the two hydrogen atoms forming an H2 molecule are totally identical by nature, the two artificial, man-made nanophotonic cavities usually are not,” Stephan Kapfinger explains. Until now, these tiny nanoscale imperfections have hampered the realization of coupled photonic elements or even larger scale photonic circuits.
The Augsburg research team used a smart trick to solve this pressing problem: they designed and employed a tiny sound wave, a nanometer earthquake on a chip, such that it compresses one of the nanocavities and simultaneously stretches the other.
This way, they are able to overcome the tiny fabrication related imperfections and make the two nanocavities identical for a very short snatch. Moreover, this happens also at a precisely defined time during the cycle of the sound wave, thus providing total control over the coupling.
Stephan Kapfinger is really enthusiastic on the success of his experiment: “It was fascinating to see that the two nanocavities don’t emit at the same color as one would naively expect. In fact they “repel” each other and the difference is simply the bond strength of the photonic molecule! Many scientists have tried hard to measure this effect but with little success.”
Hubert Krenner notes: “Our hallmark experiment not only demonstrates scaling and control at unprecedented speed. It also shows that nanomechanical waves can be efficiently converted to optical signals. This is quantum-mechanical control in the truest sense of the word.” The pioneering work and longstanding expertise of the Augsburg group on the application of surface acoustic waves (SAW) led to numerous important results and application. These cover the entire spectrum of the very active field of nanoscience and attracted large attraction worldwide. “We are very happy, that surface acoustic waves, our special tool for which we are famous here in Augsburg, led to another outstanding result in the field of nanophotonics,” Achim Wixforth proudly adds.
The studied photonic crystal devices are highly attractive because they can be scaled to large integrated circuits for light even in the quantum regime. Based on their groundbreaking experiments, the NIM research team expects that this system can now finally be extended to an optical quantum computer. Shaking and rattling them using well defined nanoquakes will be the clock of the quantum processor.
This work is supported by the Deutsche Forschungsgemeinschaft (DFG) via the Emmy Noether Programme (KR3790/2-1) and Sonderforschungsbereich SFB 631, and by the Excellence Initiative via the Cluster of Excellence Nanosystems Initiative Munich (NIM).
Stephan Kapfinger, Thorsten Reichert, Stefan Lichtmannecker, Kai Müller, Jonathan J. Finley, Achim Wixforth, Michael Kaniber and Hubert J. Krenner
Dynamic acousto-optic control of a strongly coupled photonic molecule
Nature Communications 6, 8540 (2015), doi:10.1038/ncomms9540
Prof. Hubert Krenner – firstname.lastname@example.org
Prof. Achim Wixforth – email@example.com
Lehrstuhl für Experimentalphysik I
Klaus P. Prem | idw - Informationsdienst Wissenschaft
UNH scientists help provide first-ever views of elusive energy explosion
16.11.2018 | University of New Hampshire
NASA keeps watch over space explosions
16.11.2018 | NASA/Goddard Space Flight Center
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure
Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...
09.11.2018 | Event News
06.11.2018 | Event News
23.10.2018 | Event News
16.11.2018 | Health and Medicine
16.11.2018 | Life Sciences
16.11.2018 | Life Sciences