Sub-Doppler diode laser frequency stabilization with the DAVLL scheme on the D₁ line of a ⁸⁷Rb vapor-cell

We established an experimental set-up that allows laser stabilization using the Doppler¹ and sub-Doppler^2,3 Dichroic Atomic Vapor Laser Locking (DAVLL) and the Saturated Absorption (SA) scheme. In this report we present comparative studies between Doppler and sub-Doppler DAVLL using heterodyne frequency stability measurements with an independently SA stabilized laser. Some major sources of frequency instability are discussed together with ways to improve the stability. Special focus is laid on the sub-Doppler DAVLL stabilization technique where a new approach for getting higher stability is introduced. In our measurements, the ⁸⁷Rb D₁ line was used as reference atomic line.