Researchers from the Budapest University of Technology and Economics (BME), the HUN-REN Wigner Research Centre for Physics, the University of Notre Dame in the United States, and the École Polytechnique Fédérale de Lausanne in Switzerland have addressed this problem by exploring new materials. In their study, they demonstrated that nitrogen-doped diamonds can create an energy structure under the influence of a strong magnetic field and external optical irradiation, which exhibits a laser-like phenomenon known as population inversion, providing evidence of coherent terahertz radiation emission.
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