US 5,353,115 A · System and method for generating a displacement with ultra-high accuracy using a fabry-perot interferometer

Abstract

A system and method for generating a desired displacement of an object, i.e., a target, from a reference position with ultra-high accuracy utilizes a Fabry-Perot etalon having an expandable tube cavity for resolving, with an Iodine stabilized laser, displacements with high accuracy and for effecting (as an actuator) displacements of the target. A mechanical amplifier in the form of a micropositioning stage has a platform and a frame which are movable relative to one another, and the tube cavity of the etalon is connected between the platform and frame so that an adjustment in length of the cavity effects a corresponding, amplified movement of the frame relative to the cavity. Therefore, in order to provide a preselected magnitude of displacement of the stage frame relative to the platform, the etalon tube cavity is adjusted in length by a corresponding amount. The system and method are particularly well-suited for use when calibrating a high accuracy measuring device.

Claims21

Dependent claims

A system for generating a desired displacement of an object with ultra-nigh accuracy wherein the object is movable from a reference position, the system comprising:

a Fabry-Perot etalon including a tube cavity having two ends, a length between the ends which is adjustable from a reference condition, and a pair of spherical mirrors disposed adjacent the ends thereof having a reflectivity of at least about 99.99% so as to provide the etalon with a relatively high reflectivity finesse, and the tube cavity being disposed in the aconfocal configuration and being arrangable in relation to the object so that an adjustment in length of the tube cavity effects a corresponding displacement of the object from a reference position;
and
means for controllably adjusting the length of the etalon cavity so that in order to provide a desired displacement of the object from a reference position, the length of the tube cavity is adjusted by a corresponding amount.

A system for use when calibrating a high accuracy measuring device, the system comprising:

a Fabry-Perot etalon including a tube cavity having two ends and a length therebetween which is adjustable from a reference condition, the tube cavity being arranged so that an adjustment in length thereof generates a displacement between the ends of the cavity of ultra-high accuracy, and the tube cavity including a pair of spherical mirrors disposed at the ends thereof having a reflectivity of at least about 99.99% so as to provide the etalon with a relatively high reflectivity finesse;
and
means for controllably adjusting the length of the etalon cavity so that in order to generate a displacement of desired length for purposes of calibrating a measurement device, the tube cavity is adjusted in length by a corresponding amount.

A calibration system for use when calibrating a high accuracy measuring device, the system comprising:

a micropositioning stage having a platform and a frame which are attached to one another for movement of the frame relative to the platform;
a Fabry-Perot etalon including a tube cavity having a length which is adjustable from a reference condition, the tube cavity being connected between the platform and frame of the micropositioning stage so that an adjustment in length of the tube cavity effects an amplified movement of the frame relative to the platform wherein the magnitude of the movement of the frame relative to the platform corresponds with the change in length of the etalon tube cavity as the tube cavity length is adjusted from its reference condition;
means for controllably adjusting the length of the etalon cavity so that in order to provide a preselected magnitude of displacement of the stage frame relative to the platform for purposes of calibrating a measurement device, the etalon tube cavity is adjusted in length by a corresponding amount.

A method for generating a desired displacement of an object with ultra-high accuracy wherein the object is movable from a reference position, the method comprising the steps of:

providing a Fabry-Perot etalon including a tube cavity having two ends and a length therebetween which is adjustable from a reference condition, and the tube cavity including a pair of spherical mirrors disposed at the ends thereof having a reflectivity of at least about 99.99% so as to provide the etalon with a relatively high reflectivity finesse;
arranging the tube cavity in such a relation with the object so that an adjustment in length of the tube cavity effects a corresponding displacement of the object from a reference position;
and
controllably adjusting the length of the etalon cavity so that in order to provide a desired displacement of the object from a reference position, the length of the cavity is adjusted by a corresponding amount.

1 more element

A method for calibrating a high accuracy measuring device, the method comprising the steps of:

providing a micropositioning stage having a platform and a frame which are attached to one another for movement of the frame relative to the platform;
providing a Fabry-Perot etalon including a tube cavity having a length which is adjustable from a reference condition;
connecting the tube cavity between the platform and frame of the micropositioning stage so that an adjustment in length of the tube cavity effects an amplified movement of the frame relative to the platform wherein the magnitude of the movement of the frame relative to the platform corresponds with the change in length of the etalon tube cavity as the tube cavity length is adjusted from its reference condition;
and
controllably adjusting the length of the etalon cavity so that in order to provide a preselected magnitude of displacement of the stage frame relative to the platform for purposes of calibrating a measurement device, the etalon tube cavity is adjusted in length by a corresponding amount.

2 more elements

Dependencies are inferred from the claim text.

System and method for generating a displacement with ultra-high accuracy using a fabry-perot interferometer

Life of this patent

System and method for generating a displacement with ultra-high accuracy using a fabry-perot interferometer

Life of this patent

Abstract

Claims21