The Purcell effect and Lamb shift were discovered in the middle of the 20th century. They are connected with zero-point vibrations that always appear in a vacuum. The combination of these vibrations with a quantum system such as atom, molecule or quantum point, results in spontaneous electromagnetic radiation of the excited system, which becomes stable after that. This phenomenon is called spontaneous emission. In 1946 Edward Purcell discovered that the speed of spontaneous emission depends on surroundings of the excited system. A year later his colleagues Willis Lamb and Robert Retherford measured the influence of zero-point vibrations on fine structure of the hydrogen atoms` energy levels. Mr. Lamb won the Nobel Prize in Physics for his discoveries in 1955.
The research team consisted of scientists of ITMO University, Ioffe Physical-Technical Institute, Australian National University and VPI Development Center aimed at applicability of these quantum effects in photonics. Unlike electrons, photons have no charge and rest mass; zero-point vibrations of photons needn`t low temperature and nanometer accuracy.
The researchers analyzed a behavior of light using a waveguide and a microresonator setting them close to each other. Owing to wave nature of photons they penetrate from the waveguide to the microresonator and vice versa. The waveguide also has two reflectors that provoke one more resonator with a low Q-factor. According to the experiment, the distance between reflectors affects the lifetime of photons in the microresonator. It is the Purcell effect applied for massless particles. Besides, Lamb shift is demonstrated with one distinction: instead of electron`s energy level the resonance frequency of microresonator has been changed.
According to Mr. Rybin, one of the authors of the article, the results of the research can be applied for development of optoelectronic devices such as elements of optical memory. Besides, it is very easy to influence the quality change of microresonators` characteristics.
“About ten years ago all modern computers quickly became out-of-date. However the situation has changed five years ago. Nowadays more and more people suppose that in the nearest future it will be impossible to increase computational capacity of computers because electrons have constant mass and charge. That is why one cannot increase operation frequency of devices making them smaller. Photon-based systems` development is an alternative way of the progress, the lack of mass makes photons faster than electrons. Our research is the first step towards photonic devices, integrated systems and optical computers. We found out that even without optimization of system parameters one can modify the lifetime of photons by at least 25 times,” said Mikhail Rybin, senior researcher of Chair of Nano-Photonics and Metamaterials.
Read the article here.
