Extended cavity diode lasers with tracked resonances

TL;DR

This paper introduces a simple, cost-effective method to enhance the stability and mode-hop free operation of extended cavity diode lasers by stabilizing the internal cavity resonance through noise minimization, applicable to existing systems.

Contribution

The authors propose a novel stabilization technique based on minimizing noise to maintain mode-hop free operation without modifying optical setups.

Findings

Achieved long-term mode-hop free operation in two ECDLs

Demonstrated low noise performance at low power consumption

Applicable to inexpensive non-antireflection coated diodes

Abstract

We present a painless, almost-free upgrade to present extended cavity diode lasers (ECDLs), which improves the long term mode-hop free performance by stabilizing the resonance of the internal cavity to the external cavity. This stabilization is based on the observation that the frequency or amplitude noise of the ECDL is lowest at the optimum laser diode temperature or injection current. Thus, keeping the diode current at the level where the noise is lowest ensures mode-hop free operation within one of the stable regions of the mode chart, even if these should drift due to external influences. This method can be applied directly to existing laser systems without modifying the optical setup. We demonstrate the method in two ECDLs stabilized to vapor cells at 852 nm and 895 nm wavelength. We achieve long term mode-hop free operation and low noise at low power consumption, even with an inexpensive non-antireflection coated diode.