Title: Monochromatic knots and other unusual electromagnetic disturbances: light localised in 3D,
Abstract: We introduce and examine a collection of unusual electromagnetic
disturbances. Each of these is an exact, monochromatic solution of Maxwell's
equations in free space with looped electric and magnetic field lines of finite
extent and a localised appearance in all three spatial dimensions. Included are
the first explicit examples of monochromatic electromagnetic knots. We also
consider the generation of our unusual electromagnetic disturbances in the
laboratory, at both low and high frequencies, and highlight possible directions
for future research, including the use of unusual electromagnetic disturbances
as the basis of a new form of three-dimensional display.