Scientists from the Institute of Applied Physics of the Russian Academy of Sciences, together with colleagues from the Institute of Chemistry of High Purity Substances of the Russian Academy of Sciences, developed and created an optical microresonator from a new high-purity tellurite glass with a factor of quality of more than 25 million. Due to the high record achieved value of the quality factor (for microresonators based on tellurite lenses) and the huge optical nonlinearity of this microresonator, it was possible to implement the cascade generation of narrowband radiation up to the fourth order inclusive on the effect of stimulated the Mandelstam-Brillouin scattering. On the basis of such microresonators, miniature supersensitive sensors, biosensors and other devices can be created.
The microresonator manufactured by the authors is a ball with a diameter of 75 micrometers made of specially synthesized glass based on tellurium dioxide with the addition of tungsten, lanthanum and bismuth dioxides. Inside the resonator, the light propagates near the equator. Making a gigantic number of revolutions before leaving the resonator, the light increases its intensity by several orders of magnitude. Because of this, at low pump powers, on the order of a milliwatt or less, it is possible to realize nonlinear optical effects, including stimulated Mandelstam-Brillouin scattering.
In this case, the radiation from the bomb creates a hypersonic wave, in which the light is scattered in the opposite direction with a decrease in frequency by an amount determined by the properties of the material. Due to the presence of a resonator, a first-order Brillouin wave is generated from the noise. If its power is high enough, then a cascade process is possible: a first-order Brillouin wave creates its own hypersonic wave, in which the light is scattered and a second-order Brillouin wave is generated, which in turn pumps a third order. order wave, etc.
The proposed theoretical model made it possible to explain in detail the experimental results and reveal the essential factors of the ongoing physical processes. The authors conducted experimental studies in the telecommunications range (radiation wavelength ~ 1.5 μm), but potentially microcavities based on synthesized glass can be used in a much wider spectral range – from 1 to 3-5 μm, which is impossible when microcavities are fabricated from standard silicate glasses.
Article published in Sensors magazine.
This work was supported by Russian Science Foundation grant 20-72-10188.