Precision laser spectroscopy in fundamental studies

Abstract

The role of precision spectroscopic measurements in the development of fundamental theories is discussed, with particular emphasis on the hydrogen atom, the simplest stable atomic system amenable to the accurate calculation of energy levels from quantum electrodynamics. Research areas that greatly benefited from the participation of the Lebedev Physical Institute are reviewed, including the violation of fundamental symmetries, the stability of the fine-structure constant a, and sensitive tests of quantum electrodynamics.

Partial Compensation of Thermal Noise in the Fundamental Mode of an Optical Cavity

“…Highly-stable optical cavities are widely used in experiments related to precision optical measurements: for registration of gravitational waves [1], searches for dark matter [2,3], highresolution spectroscopy in optical atomic clocks [4,5], and in other fundamental research [6,7] Stabilization of laser radiation frequency by reference monolithic high-Q Fabry-Perot cavities using the Pound-Driver-Hall (PDH) technique [8] allows to reduce spectral linewidth to values less than 100 mHz [9][10][11].…”