Light modulation apparatus and optical switch, movement detecting device and distance measuring device, alignment device and semiconductor aligner, and processes thereof

A movement detecting device comprising:

• first and second periodic structures each having a period smaller than the wavelength of light emitted from a light source;
• a moving means for relatively moving the two periodic structures,
• wherein the surface of the first periodic structure is brought near to the surface of the second periodic structure to a space not longer than the wavelength to arrange them in a state opposed to each other, the light incident on the first periodic structure is converted into near-field light by the first periodic structure, and the converted near-field light is transmitted through the second periodic structure and scattered on the back surface of the second periodic structure,
• a means for detecting the intensity of the scattered light;
• and
• a means for detecting the quantity of relative movement between the first and second periodic structures.

An alignment device between two substances, comprising:

• first and second periodic structures each having a period smaller than the wavelength of light emitted from a light source;
• wherein one of the periodic structures is provided on one of the two substances, and the other is provided on the other of the two substances,
• a moving means for relatively moving the two substances;
• wherein the two periodic structures are arranged with a close space not longer than the wavelength in a state opposed to each other,
• a means for detecting the intensity of the transmitted light from the light source, which has been transmitted through the two periodic structures;
• and
• a means for detecting the relative positions of the first and second two periodic structures based on the intensity detected;
• wherein the moving means is driven on the basis of the relative positions detected, whereby relative alignment between the two substances is conducted.

A light modulating process comprising the steps of:

• arranging first and second periodic structures each having a period smaller than the wavelength of light emitted from a light source in a state opposed to each other in such a manner that the surface of the first periodic structure is brought near to the surface of the second periodic structure to a space not longer than the wavelength;
• converting the light incident on the first periodic structure into near-field light by the first periodic structure;
• causing the converted near-field light to pass through the second periodic structure to convert it into propagation light by scattering the near-field light on the back surface of the second periodic structure;
• and
• relatively moving the two periodic structures by a moving means, thereby modulating the intensity of the propagation light.

A movement detecting process comprising the steps of:

• arranging first and second periodic structures each having a period smaller than the wavelength of light emitted from a light source in a state opposed to each other in such a manner that the surface of the first periodic structure is brought near to the surface of the second periodic structure to a space not longer than the wavelength;
• converting the light incident on the first periodic structure into near-field light by the first periodic structure;
• causing the converted near-field light to pass through the second periodic structure to convert it into propagation light by scattering the near-field light on the back surface of the second periodic structure;
• and
• detecting the intensity of the scattered light to detect the quantity of relative movement between the two periodic structures from the intensity of the scattered light detected.

An aligning process between two substances, comprising the steps of:

• providing one of first and second periodic structures each having a period smaller than the wavelength of light emitted from a light source on one of the two substances, and providing the other on the other of the two substances;
• arranging the two periodic structures with a close space not longer than the wavelength in a state opposed to each other:
• detecting the intensity of the transmitted light from the light source, which has been transmitted through the two periodic structures;
• detecting the relative positions of the first and second two periodic structures based on the intensity detected;
• and
• moving the relative positions of the two substances based on the relative positions detected, thereby conducting alignment between the two substances.