3D Nanowaveguide Fiber Modes

This is the cylindrical counterpart to a planar nanowaveguide: a step-index optical fiber, orbit-able in 3D, whose guided-mode intensity pattern is built from thousands of individually placed field samples rather than a flat texture. Each sample's brightness comes from the real fundamental-mode radial profile (the Marcuse Gaussian approximation used across fiber-optics engineering) and, once the V-number crosses the 2.405 single-mode cutoff, a second LP11 lobe pattern blends in to show the azimuthal structure of the next guided mode. Tune the core radius, wavelength and index contrast to watch the fiber cross from strictly single-mode into multi-mode operation in real time.