Method and apparatus for all-optical spatial frequency domain scanning for broadband high-precision measurement
AssigneeElectronics and Telecommunications Research Institute
InventorsYongjun LIM, Kwan Jung OH
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Abstract
A transmissive digital holographic metrology apparatus, the apparatus comprises: a light source unit that emits light; a beam splitter that divides the light emitted from the light source unit; a reference arm that forms a reference beam from the divided light; an object arm that forms an object beam passing through an object from the divided light; an interference unit that interferes the object beam with the reference beam with each other to generate an interference result; and an image sensor that records the interference result as a two-dimensional image to acquire one or more interference patterns.
Claims20
A transmissive digital holographic metrology apparatus, the apparatus comprising:
- a light source unit that emits light;
- a beam splitter that divides the light emitted from the light source unit;
- a reference arm that forms a reference beam from the divided light;
- an object arm that forms an object beam passing through an object from the divided light;
- an interference unit that interferes the object beam with the reference beam with each other to generate an interference result;
- and
- an image sensor that records the interference result as a two-dimensional image to acquire one or more interference patterns,
- wherein the object arm further includes a predetermined optical scanning device,
- wherein the predetermined optical scanning device comprises a spatial light modulator (SLM), a microlens array, and a condenser lens,
- wherein a digital micromirror device (DMD) is used as the spatial light modulator, and
- wherein the microlens array is inserted between the DMD and the condenser lens.
A reflective digital holographic metrology optical apparatus, the apparatus comprising:
- at least one beam splitter that divides incident light into an object beam and a reference beam;
- at least one polarization beam splitter that polarizes at least one of the object beam or the reference beam;
- an object reflection unit that forms reflected light using the object beam;
- an interference unit that interferes the reflected light and the reference beam with each other to generate an interference result;
- and
- an image sensor that records the interference result as a two-dimensional image to acquire one or more interference patterns,
- wherein the incident light is generated through a predetermined optical scanning device,
- wherein the predetermined optical scanning device comprises a spatial light modulator (SLM), a microlens array, and a condenser lens,
- wherein a digital micromirror device (DMD) is used as the spatial light modulator, and
- wherein the microlens array is inserted between the DMD and the condenser lens.
A method for acquiring digital hologram image, the method comprising:
- emitting light from a light source;
- dividing the emitted light;
- forming a reference beam from the divided light;
- forming an object beam that passes through an object from the divided light;
- interfering the object beam and the reference beam with each other to generate an interference result;
- and
- recording the interference result as a two-dimensional image to acquire one or more interference patterns,
- wherein the step of forming the object beam includes performing a predetermined optical scanning,
- wherein the predetermined optical scanning is performed using a spatial light modulator (SLM), a microlens array, and a condenser lens,
- wherein a digital micromirror device (DMD) is used as the spatial light modulator, and
- wherein the microlens array is inserted between the DMD and the condenser lens.
A method for acquiring digital hologram image, the method comprising:
- dividing incident light into an object beam and a reference beam;
- polarizing at least one of the object beam and the reference beam;
- forming reflected light using the object beam;
- interfering the reflected light and the reference beam with each other to generate an interference result;
- and
- recording the interference result as a two-dimensional image to acquire one or more interference patterns,
- wherein the incident light is generated as a result of performing a predetermined optical scanning,
- wherein the predetermined optical scanning is performed using a spatial light modulator (SLM), a microlens array, and a condenser lens,
- wherein a digital micromirror device (DMD) is used as the spatial light modulator, and
- wherein the microlens array is inserted between the DMD and the condenser lens.
Dependencies are inferred from the claim text.