Extending antenna theory to the optical domain

We describe an algorithm that yields new design rules for linear wire optical antennas. The ground work of our analysis is to derive first, and then solve, an integro-differential equation that gives the current on the wire antenna, at optical frequencies. Consequently, we compute the near field of these antennas, and thereby determine their equivalent-circuit parameters. An illustrative example is the effective length of a linear wire antenna, whereby we evaluate the field enhancement achievable at the feed gap.