Methods and systems for measuring optical characteristics of objects

The method as claimed in any one of the preceding claims, wherein the method comprises rotating the state of polarisation of the measurement beam a plurality of times by way of a corresponding number of holograms.

The method as claimed in any one of the preceding claims, wherein the at least one optical characteristic of the object measured is birefringence.

The method as claimed in any one of the preceding claims, wherein the each of the holograms is configured to interact with a pair of incident light beams to produce the uniformly polarised measurement beam having a predetermined polarisation state.

The method as claimed in any one of the preceding claims, wherein each of the holograms comprise at least two holograms superimposed and arranged to interact with incident light beams to produce the uniformly polarised measurement beam.

The method as claimed in any one of the preceding claims, wherein the method comprises:

• detecting the polarisation properties of the measurement beams after interacting with the object to generate polarization measurement values, wherein the polarization measurement values represent output polarization states of the measurement beams, after interacting with the object;
• and
• detecting the polarisation properties of the measurement beams without interacting with the object to generate polarization reference values, wherein the polarization reference values represent output polarization states of the measurement beams without interacting with the object.

The method as claimed in any one of the preceding claims, wherein the method comprises:

• splitting a light beam from a light source into two paths with differently polarised beams travelling in the two paths;
• providing the holograms to interact with the two paths, wherein each of the holograms comprise a hologram which interacts with one polarised beam, and another superimposed hologram which interacts with the other differently polarised beam thereby to modulate both differently polarised beams to make first diffraction orders of both polarised beams with uniform polarisation come out of the hologram together to be used as the measurement beam.

The method as claimed in any one of the preceding claims, wherein the method comprises directing the measurement beams through a first polarising element prior to interacting with the object.

The method as claimed in any one of the preceding claims, wherein the method comprises directing the measurement beams through a second polarising element after interacting with the object.

The method as claimed in any one of the preceding claims, wherein the method comprises storing the detected polarization properties associated with the measurement beams without interacting with the object and after interacting with the object in a suitable memory device for processing to determine the measurement of at least one optical characteristic of the object.

The method as claimed in any one of the preceding claims, wherein the method comprises directing the measurement beams through one or more Fourier imaging systems before detecting the polarisation properties.

The system as claimed in any one of the preceding claims, wherein the beam generating arrangement comprises a light source in the form of a laser light source.