US 10,119,903 B2Granted

Interferometric ellipsometry and method using conical refraction

AssigneeAdom, Advanced Optical Technologies Ltd.

InventorsYoel Arieli, Yoel Cohen

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Abstract

An apparatus and method for determining optical properties of an object includes a tunable monochromatic light source and an optical system for illuminating at least one point of the object with light from the light source, and collecting light reflected from the object. A biaxial birefringent crystal intercepts a beam of light reflected from the object and propagates the beam along an optical axis of the crystal and transforms the beam of reflected light to a ring of light having a periphery, each point of which has a different polarization plane. A detector array detects respective points along the periphery of the ring and a processing unit is coupled to the detector and is responsive to signals thereby for determining optical properties of the object.

Claims12

Dependent claims

An apparatus comprising:

a tunable monochromatic light source configured to illuminate at least one point of an object;
a polarizer configured to be disposed between the light source and the object, the polarizer being configured to polarize light from the light source;
a biaxial birefringent crystal (a) positioned to intercept a beam of light reflected from the object, (b) positioned to propagate the beam along an optical axis of the crystal, and (c) configured to transform the beam of reflected light into a ring of light, (i) each point of the ring of light having a different polarization plane, and (ii) a diameter of the ring of light being different for different respective wavelengths of the light from the tunable monochromatic light source;
and
a detector array configured to simultaneously detect respective points along the ring of light for each of a plurality of wavelengths of the tunable monochromatic light source, such that images are acquired by the detector array at different wavelengths, one at a time.

2 more elements

A method comprising:

determining at least one optical property of at least a portion of an object by:
illuminating at least one point of the object with light from a tunable monochromatic light source;
directing light reflected from the object on to a biaxial birefringent crystal, such that light reflected from the object is propagated along an optical axis of the crystal so as to transform the reflected light to a ring of light, (i) each point of the ring of light having a different polarization plane and (ii) a diameter of the ring of light being different for different respective wavelengths of the light from the tunable monochromatic light source;
spectrally tuning the light source to generate light at a plurality of wavelengths;
simultaneously detecting respective points of the ring of light for different respective wavelengths of the reflected light, one wavelength at a time;
and
processing the detected respective points to determine at least one optical property of the object.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/991,197Filed 29 May 2018 · continuation
Priority: 26 Jan 2014
Published: US 2018/0275047 A127 Sep 2018
Granted: 6 Nov 2018
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G01N 21/211
Polarisation-affecting properties: ellipsometry
G01B 9/02091
Low-coherence interferometers: tomographic interferometers, e.g. based on optical coherence
G01N 21/45
Refractivity; Phase-affecting properties, e.g. optical path length: using interferometric methods; using Schlieren methods
G01B 2290/70
Aspects of interferometers not specifically covered by any group under G01B9/02: using polarization in the interferometer

Family

Application61/931,626Us provisional application · filed 26 Jan 2014
Application61/948,116Us provisional application · filed 5 Mar 2014
PCT/IL2015/050077Parent of this continuation · filed 22 Jan 2015
US 2018/0275047 A1Pre-grant publication · published 27 Sep 2018
Application15/113,161Parent of this continuation
US 10,024,783 B2Related patent
US 2017/0023464 A1Published application
US 10,119,903 B2This patent

From the US filing history. Foreign family members aren’t listed.

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