Abstract

External-cavity diode lasers (ECDLs) operating in the near infra-red spectral range have become a standard tool in the field of atomic physics as well as in bio-medical applications. Applications of conventional ECDLs in Littrow as well as in Littman/Metcalf configuration suffer from their sensitivity on ambient conditions such as vibrations, acoustics, and temperature variations [1]. Furthermore, advanced applications require a narrower linewidth below 100 kHz as well as a high output power in the several hundred milliwatts regime. Applying external-cavity feedback from volume holographic gratings (VHGs), consisting of photo-thermo-refractive glass with a high damage threshold, has proven to stabilize and simplify ECDLs [2]. So far VHG stabilized external cavity configurations suffered either from an output power below hundred milliwatts if a ridge laser was employed or from a poor beam profile and high optical linewidth if a diode laser bar was used [3].

© 2015 IEEE