Red-Emitting Distributed Bragg Reflector Lasers for Strontium-Based Optical Atomic Clocks

Optical atomic clocks based on the spectroscopy of strontium (Sr) atoms currently provide the most accurate time and frequency measurements. They reach fractional frequency uncertainties in the range of 10
⁻¹⁸
[1], which makes them promising candidates for the redefinition of the second and for improving, for example, the accuracy of satellite navigation.