KAIST’s Department of Physics Professor Han-Seok Lee and Professor Yong-Hee Lee implemented a Brillouin laser on a semiconductor chip that operates with 100 times lower pump energy than before.
Improving the measurement accuracy of ultra-precise sensors such as distance and rotation sensors for autonomous driving
(Daejeon = Sejong Chungcheong News) Reporter Song Yoon-young = KAIST is a joint research team of Professors Lee Han-seok and Professor Lee Yong-hee of the Department of Physics (first-generation collaboration laboratory), through joint research with the research team of Professor Moo-Han Choi of Kyungpook National University and Professor Deok-Yong Choi of National University of Australia. It announced on the 23rd that it has succeeded in implementing the Rouen laser. The ultra-compact, low-power, and low-noise light source with almost no frequency fluctuations is a key element required for the construction of a next-generation ultra-precise optical sensor.
▶ Brillouin laser: *Based on Brillouin scattering, laser light is generated and amplified, so the more easily the medium of the laser causes Brillouin scattering, the less energy can be operated. The output laser light has a lower frequency fluctuation and very low noise than the input pump light.
▶ Brillouin scattering: A phenomenon in which light interacts with a medium to generate acoustic phonons and scatter them. The scattered light undergoes a frequency reduction corresponding to the energy of the sound wave, and can be used in laser construction because it is possible to replicate the light of the same characteristic as stimulated emission.
The joint research team maximized the performance by developing a Brillouin laser based on a chalcogen compound glass that causes Brillouin scattering hundreds of times better than conventional materials. Chalcogen compound glass has a fundamental weakness in that it is difficult to form by etching on a chip due to its chemical instability, but the research team solved this problem by developing a new fabrication technique in which an optical element is spontaneously formed during the deposition process.
The manufacturing technique developed by the research team can be compared to obtaining the desired shape of snow by controlling only the shape of the roof without directly touching the snow, since the shape of the snow accumulated on the roof in winter is determined by the shape of the roof. In other words, it was the first to prove that when a floor structure is properly formed using silicon oxide, which is easy to process with the current semiconductor process technology, an optical element with excellent performance is spontaneously formed by simply depositing a chalcogen compound glass thereon.
The joint research team succeeded in implementing a high-performance Brillouin laser based on chalcogen compound glass in the form of a microscopic optical device on a semiconductor chip using this fabrication technique developed in-house. In addition, it was revealed that the laser can be driven with a pump energy that is more than 100 times lower than the previous record.
An official of the joint research team said, “miniaturization and low-power drive are essential elements for commercialization.” It is expected that it will be widely used,” he said.
He also added meaning that “the new process technique developed in the research process is not only very meaningful in that it introduced and made possible various materials that could not be used so far, and it is a source technology that is likely to be widely used in the future.” did.
Corresponding author Prof. Han-Seok Lee, who led the study, predicted, “Calcogen compound glass can be applied to the mid-infrared band where absorption lines of various molecules exist, so it will be able to expand its application range to environmental monitoring and healthcare fields based on molecular spectroscopy.” Another corresponding author, Prof. Deok-Yong Choi, said, “The process technique developed in the research process enables hybrid integration of various materials and can be applied to the fields of high-efficiency quantum light sources and quantum memories, which are the key elements of the future quantum Internet. ˮ and emphasized.
This thesis of a joint research team, which was co-authored by Dr. Dae-Gon Kim from KAIST Department of Physics and Postdoctoral Researcher Han Sang-yoon (currently Professor of Daegu-Gyeongbuk Institute of Science and Technology) as the co-first author, was published in the international journal Nature Communications on November 23rd. (Paper name: Universal light-guiding geometry for on-chip resonators having extremely high Q-factor)
Meanwhile, this research was selected for the 2018 Samsung Future Technology Promotion Project and was conducted with continuous support.
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