Jul 29, 2020
Recently, an international team of researchers led by researchers from ITMO University（Russia）announced that it has developed the world's most compact semiconductor laser in the visible light range at room temperature. This laser is a nanoparticle with a size of only 310 nanometers (3000 times smaller than a millimeter), which can produce green coherent light at room temperature and can even be seen through a standard optical microscope.
It is worth mentioning that scientists have successfully overcome the green part of the visible light band. The main researcher of this article, Sergey Makarov, a professor at the School of Physics and Engineering of ITMO University, said: “In modern light-emitting semiconductors, In the field, there is a "green gap" problem." The green gap means that the quantum efficiency of conventional semiconductor materials used in light-emitting diodes drops sharply in the green part of the spectrum. This problem hinders the development of room temperature nanolasers made of conventional semiconductor materials. . "
The ITMO University research team chose perovskite halide as the material for its nano laser. Traditional lasers consist of two key elements: an active medium that allows coherent excitation and emission and an optical resonator that helps to confine electromagnetic energy inside for a long time. Perovskite can provide these two properties: a certain shape of nanoparticles can act as both an active medium and a high-efficiency resonator. Scientists successfully created 310-nanometer-sized particles, which when excited by femtosecond laser pulses, can generate laser radiation at room temperature.
In fact, the volume of small lasers usually has a cubic relationship with the emitted wavelength, and since the wavelength of green light is only 1/3 of that of infrared light, green lasers can be made smaller. This is essential for producing ultra-compact components for future optical computer systems.