Speed at its limits
Physicists develop ultra-fast semiconductor nano-lasers
The fastest, in this case means the speed at which the laser can be turned on and off and not the length of laser pulse, as Prof. Dr. Carsten Ronning from the University of Jena clarifies. “While the fastest lasers typically need several nanoseconds for one cycle our semiconductor nano-laser only needs less than a picosecond and is therefore a thousand times faster,“ the solid state physicist continues.
For their nano lasers the researchers use tiny wires made of zinc oxide. These wires have diameters of a few hundreds of nanometres – around a thousandth of the diameter of human hair - and are about a few micro meters long. Their properties make these nanowires an active laser medium and a resonator at the same time. “Light is being reflected at the ends of the nanowire, similar to a mirror, and is then amplified while propagating through the nanowire,“ says Robert Röder. The PhD student in Prof. Ronning’s team is one of the authors on this current publication.
For the researchers the concept of using nanowires as a laser is not new. However, the new idea in this publication is the possibility to fundamentally modify the speed of these lasers. To this end the physicists combined the semiconductor with a metallic layer, leaving only a 10 nanometer thin gap layer between both in which the light field is constricted. “This is how light-matter interactions are accelerated,“ says Robert Röder. This is not only “world record“ regarding the switching speed. “Most likely we also achieved the maximum possible speed, at which such a semiconductor laser can be operated“. Applications for these ultrafast und nanometre small lasers are especially optical transistors and sensors. “Using such tiny sensors single molecules or microbes can be detected in medical diagnostics“, emphasizes Prof. Ronning.
Original publication
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Topic world Sensor technology
Sensor technology has revolutionized the chemical industry by providing accurate, timely and reliable data across a wide range of processes. From monitoring critical parameters in production lines to early detection of potential malfunctions or hazards, sensors are the silent sentinels that ensure quality, efficiency and safety.