Near-UV laser diodes for external cavity lasers

Group III-nitride based laser diodes constitute efficient sources of laser light in the near-UV to green spectral range [1]. Such laser diodes are commercially available with output powers ranging from few mW to several 100mW. However, the wavelengths of these commercial diodes mainly fit to the common applications, namely data storage and laser projection. On the other hand, scientific applications in spectroscopy or quantum optics often need specific wavelengths not covered by commercial devices. For such applications, external cavity diode laser modules are typically employed in order to meet the high requirements on linewidth, stability and tunability of the emission wavelength.