The past few years have brought to life a new class of semiconductor diode lasers, spanning the spectral range from the violet to the green, based on wide band gap semiconductors. The first laser demonstrations in the blue/green were made in ZnSe-based quantum well (QW) heterostructures [1]. This has been followed by the rapid recent developments in the GaN-compounds that have brought the latter devices to the threshold of technological viability [2]. The presentation by S. Nakamura in this Jablonski Centennial Conference offers several examples of the progress with the light emitting nitride devices, including LEDs that span the wavelength range from near ultraviolet to amber. In this paper we focus on the rich realm of optical physics that the wide band gap semiconductor lasers offer, specifically in terms of light-matter coupling within a high density two-dimensional system electron-hole in a ZnCdSe or InGaN quantum well. Although these ternary compounds that define active optical media are expected to be rather similar in terms of (effective mass theory) expectations, namely that strong Coulomb (excitonic) correlations are much more dominant that in conventional semiconductor lasers, we find considerable contrasts between the wide gap II-VI and III-V systems at present. The many-electron contributions to the physics of optical gain and stimulated emission in the nitride diode lasers are largely masked by the presence of a significant amount of spatial compositional fluctuations in the InGaN QW material. The disorder arises from the