Refractive index changes in all types of optical media induced by an optical field through resonant and nonresonant mechanisms with submicrosecond responses are surveyed in this paper. Relevant data for over 100 representative media have been compiled and tabulated, and numerical examples have been worked out for several important media. For room-temperature operation, solid polydiacetylenes, CS2 liquid, and N2-buffered 12 vapor are found to be roughly comparable in sensitivity for self-induced phase shift for a given transmission loss. Nitroaniline compounds are somewhat less sensitive but also interesting. For operation in the 10 µm region, n-InSb is most sensitive. If operation at somewhat elevated temperature (100 to 200 C) is acceptable, then N2-buffered alkali-metal vapors are the best with about two orders of magnitude higher sensitivity. At liquid nitrogen temperature, a thin film of CdS could be as sensitive as a 105 times thicker sample of PTS polydiacetylene if the signal frequency is near the intrinsic exciton lines of CdS.