AbstractWe recently suggested that careful optimization of residual strain in nitride laser structures could be used to extend the operating wavelength into the red and infrared spectral region (Sharma and Towe, J. Appl. Phys. 106, 104509 (2009) and Appl. Phys. Lett. 96, 191105 (2010) [1, 2]). At the other wavelength extreme, in the ultraviolet, non‐optimal residual strain in nitride emitters with AlGaN layers and large crystal‐field splitting energies can cause a switching in emitted light polarization characteristics, leading to less efficient devices. Although Al‐rich AlGaN quantum wells favour shorter emission wavelengths, these structures also exhibit poor carrier confinement. These factors suggest that even in the ultra‐violet, the key limiting constraint for the development of lasers is the amount of residual strain in the structures. To properly resolve these issues, a critical analysis of strain, quantum confinement, and the polarization properties of nitride quantum well structures is warranted (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)