Chiral content of electromagnetic pulses

The integral over all of space of the chiral density of an electromagnetic pulse is constant in time. We evaluate the chiral content, energy, momentum, and angular momentum of a general causal pulse of a given type in terms of the wavenumber weight function which defines the fields. The types of pulse considered are transverse electric (TE), transverse magnetic (TM), and the self-dual forms TE+iTM and 'CP' (circularly polarized; the quotation marks are used because the pulses can be exactly circularly polarized only in the plane wave limit). TE and TM pulses are shown to have zero total chiral content, for all possible causal waveforms. Formulae are given for the total chiral content of self-dual TE+iTM and 'CP' pulses. In wavenumber space, the chiral density of self-dual pulses is just +/- 8 pi k times the energy density.