quantum information


Scientists discover diamond defects can secure data transmission and measure temperatures

  • April 23, 2023
Scientists discover diamond defects to secure data transmission and measure temperatures
The black-and-white picture shows a microdiamond crystal as seen with a scanning electron microscope. The overlaid blue square with scattered spots of color is a fluorescence microscopy image highlighting the new color centers discovered by the authors of the study. These are defects that re-emit previously absorbed light in a narrow spectral range. Namely, as seen in the graph to the right, most of the emission occurs at a wavelength of about 630 nanometers. This peak has the merit of being clearly discernible, and it shifts depending on ambient temperature, allowing the diamond to be used as a remote temperature sensor. Credit: Arthur Neliubov/Skoltech

Scientists from Skoltech, Moscow Pedagogical State University, and other research centers have discovered a new class of defects in diamond that may be of use for quantum information processing and precise and remote temperature measurements within very small objects, such as living cells. The findings are reported in a letter published in Physical Review B.

Color centers are an umbrella term for defects of various nature in a transparent crystal, usually diamond. Typically, a color center is a foreign atom, such as nitrogen, incorporated into the crystal lattice of diamond, with one or more nearby carbon atoms missing.

What gives color centers their name are their optical properties. While diamond itself is transparent to visible light, color centers are spots in it that have the technologically appealing capacity to absorb light and effectively re-emit it in a rather narrow spectral band—that is, with a very specific color (wavelength). Importantly, color centers can effectively emit single photons. There are several potential applications where this narrow-band single-photon emission comes in handy.

Single photons are building blocks for quantum optics and quantum information applications. For example, such photons are useful for the ultimate data security technology—quantum encryption.

Read the rest