Use of Macroscopic Solid Structure in Accelerators

Use of structures of a solid in accelerators is discussed, which have sizes around the wavelength of lasers. An example is a photonic band-gap crystal, an artificial periodic structure made from two materials with different dielectric constants. Another simpler example is a fine hole in a solid, in which electromagnetic waves transmit as low-dimensional waves. One of the applications of the photonic band-gap crystal is guiding of laser pulses over a Rayleigh length. The hole in a metal holds plasmons on the inner wall, whose electric fields can accelerate charged particles. A plasmon linac, a linac based on this principle, can realize an emittance on the order of nm.