Use of submillimeter waveguide for laser transverse mode control, four-wave parametric frequency conversion, ultrafast broadband radiation generation and optical pulse shortening are presented. This paper begins with a general introduction to the applications of submillimeter waveguide to laser physics and nonlinear optics. Transverse mode selection by using an intracavity capillary is then described. Nonlinear optical frequency conversion in gas-filled hollow dielectric and hollow metallic waveguide structures is discussed. Applications of submillimeter liquid-core fiber to stimulated scattering, ultrafast broadband radiation generation and optical pulse shortening are presented, and transient stimulated Rayleigh-Kerr scattering is proposed to explain the observations of these nonlinear optical processes. It is shown that the unique characterization of high usable pump power and high power emission of submillimeter waveguides makes the waveguide structures ideal for high-power, high-energy laser physics and nonlinear optics.
