Wavelength tuning of VECSELs by cavity geometry

In this paper we report on the wavelength tuning of a VECSEL by changing the cavity geometry. The development and demonstration of a tunable high power single frequency Vertical External Cavity Surface Emitting Lasers (VECSEL) operating at various wavelengths from the UV to the IR region of the spectrum have been reported in many papers. However, it is important to understand that in many instances a precise lasing wavelength is required for proper operation. For example, VECSELs have been designed to specifically interact with the sodium spectral lines. If the VECSEL growth is not adequate, it may not be possible to reach the desired wavelength in a traditional cavity where the intracavity mode interacts with the VECSEL chip at normal incidence. Here we notice that if a fold angle is introduced at the VECSEL chip, a spectral blue shift occurs, and extended tunability may be possible. Therefore, by altering the cavity geometry it may be possible to further optimize a VECSEL design to obtain maximum output power at a desired wavelength.