Beam generation method and system

A system for generating a radiation pattern in a target plane, the system comprising:

• (a) an illumination arrangement for emitting a beam of radiation;
• (b) an optical arrangement accommodated in an optical path of said beam;
• (c) a first optical medium of refraction index n1 deployed in said optical path;
• and (d) a second optical medium of refraction index n2 deployed in said optical path, where n2<n1, the target plane being located within said second optical medium,
• wherein said illumination arrangement is configured to emit radiation having a wave number A defined by 2π/λ where is the wavelength of said radiation in said second medium, wherein said optical arrangement is configured for producing from said beam a propagating radiation pattern propagating in said first optical medium and incident on an interface between said first optical medium and said second optical medium, said optical arrangement being configured to generate said propagating radiation pattern in such a manner that substantially all spatial frequency components y of a resulting field of said propagating radiation pattern are greater than said wave number k such that said propagating radiation pattern generates a focused evanescent radiation pattern at said target plane with substantially zero propagating components within said second medium.