Focus enhancing electromagnetic wave propagating device

A method for focusing an electromagnetic wave that propagates from a wave emanating block in a wave-propagating direction into a focusing light spot, the method comprising the step of:

• providing a focus enhancing electromagnetic wave propagating device including a main body that has surfaces capable of blocking propagation of the electromagnetic wave, and that includes an incident side and an exit side opposite to the incident side in the wave-propagating direction, the main body being formed with a main wave-propagating structure that extends from the incident side to the exit side, that defines a central axis, and that is adapted to allow the electromagnetic wave to propagate from the wave emanating block therethrough for focusing into a focusing light spot;
• wherein the main body is further formed with an auxiliary wave-propagating channel that extends from the incident side to the exit side, that has an inner dimension not greater than the wavelength of the electromagnetic wave, and that defines a channel axis, which is parallel to the central axis, the main wave-propagating structure having an exit end at the exit side of the main body, the auxiliary wave-propagating channel having an exit opening at the exit side of the main body, the auxiliary wave-propagating channel being adapted to allow the electromagnetic wave to propagate from the wave emanating block therethrough toward the focusing light spot;
• wherein a phase difference is present between the electromagnetic wave after traveling through the main wave-propagating structure at the exit end of the main wave-propagating structure and the electromagnetic wave after traveling through the auxiliary wave-propagating channel at the exit opening of the auxiliary wave-propagating channel, such that constructive interference is generated at the focusing light spot between the electromagnetic wave traveling through the main wave-propagating structure and the electromagnetic wave traveling through the auxiliary wave-propagating channel, the required phase difference being a function of a distance between the focusing light spot and the exit end of the main wave-propagating structure, a distance between the focusing light spot and the exit opening of the auxiliary wave-propagating channel, velocities of the electromagnetic wave after traveling through each of the main wave-propagating structure and the auxiliary wave-propagating channel, and angular frequencies of the electromagnetic wave after traveling through each of the main wave-propagating structure and the auxiliary wave-propagating channel.

A light spot generator comprising:

• a wave emanating block, from which an electromagnetic wave having a wavelength is adapted to propagate in a wave-propagating direction;
• and
• a focus enhancing electromagnetic wave propagating device including a main body that has surfaces capable of blocking propagation of the electromagnetic wave, and that includes an incident side and an exit side opposite to said incident side in the wave-propagating direction, said main body being formed with a main wave-propagating structure that extends from said incident side to said exit side, that defines a central axis, and that is adapted to allow the electromagnetic wave to propagate from the wave emanating block therethrough for focusing into a focusing light spot;
• wherein said main body is further formed with an auxiliary wave-propagating channel that extends from said incident side to said exit side, that has an inner dimension not greater than the wavelength of the electromagnetic wave, and that defines a channel axis, which is parallel to the central axis, said main wave-propagating structure having an exit end at said exit side of said main body, said auxiliary wave-propagating channel having an exit opening at said exit side of said main body, said auxiliary wave-propagating channel being adapted to allow the electromagnetic wave to propagate from the wave emanating block therethrough toward the focusing light spot;
• wherein a phase difference is present between the electromagnetic wave after traveling through said main wave-propagating structure at said exit end of said main wave-propagating structure and the electromagnetic wave after traveling through said auxiliary wave-propagating channel at said exit opening of said auxiliary wave-propagating channel, such that constructive interference is generated at the focusing light spot between the electromagnetic wave traveling through said main wave-propagating structure and the electromagnetic wave traveling through said auxiliary wave-propagating channel, the required phase difference being a function of a distance between the focusing light spot and said exit end of said main wave-propagating structure, a distance between the focusing light spot and said exit opening of said auxiliary wave-propagating channel, velocities of the electromagnetic wave after traveling through each of said main wave-propagating structure and said auxiliary wave-propagating channel, and angular frequencies of the electromagnetic wave that travels through each of said main wave-propagating structure and said auxiliary wave-propagating channel.