Research opportunities are available for a wide range of practical and basic linear and nonlinear refractive index issues. The focus is on developing new concepts and measurement methods for characterization of index of refraction properties (index dispersion, dependence on stress and temperature, birefringence, nonlinear properties, etc.), for wavelengths in the range VUV – mid IR (0.12 - 15 microns). These include: interferometric methods; optical issues, such as symmetry-breaking effects of finite momentum at short wavelengths (first measured and analyzed for practical optical materials at NIST); nonlinear effects; measurements of nano-scale materials; and a new project on the development of methods for in situ characterization of channel waveguide materials in integrated photonic structures.