Calibrating method and device for broad-band achromatic composite wave plate and corresponding measurement system

A calibrating apparatus for a composite waveplate, comprising:

• a detecting unit configured to receive or detect a measured light intensity;
• a processing unit configured to:
• determine a first matrix characterizing the composite waveplate, the first matrix including at least one unknown number:
• determine a theoretical relationship between the light intensity and an alignment angle offset value of the composite waveplate based on the first matrix;
• and
• determine a second matrix that characterizes the composite waveplate based on the determined theoretical relationship between the light intensity and the alignment angle offset value of the composite waveplate and actually measured light intensity data.

A measuring system, comprising:

• a polarizer configured to produce a polarized light based on a light source;
• a polarization analyzer configured to detect the polarized light reflected from a surface of a sample;
• and
• a detector configured to receive a light intensity of the polarized light from the polarization analyzer;
• wherein the measuring system further comprises:
• at least one composite waveplate that is disposed between the polarizer and the polarization analyzer along an optical path, and the measuring system is configured to:
• adjust the polarizer and/or the composite waveplate and/or the polarization analyzer to adjust the light intensity detected by the detector, and determine a matrix characterizing the composite waveplate based on a theoretical relationship between the light intensity and an alignment angle offset value of the composite waveplate.

A computer program product, such that when the computer program product is executed by a computer device, a calibrating method for a composite waveplate is executed, the method comprising:

• A. determining a first matrix characterizing the composite waveplate, the first matrix including at least one unknown number;
• B. determining a theoretical relationship between a light intensity and an alignment angle offset value of the composite waveplate based on the first matrix;
• and
• C. calibrating based on the theoretical relationship between the light intensity and the alignment angle offset value of the composite waveplate determined in step (B) and actually measured light intensity data to obtain a second matrix that characterizes the composite waveplate and does not contain the unknown number.

A non-volatile computer-readable medium, including computer code which, when being executed by the computer code, causes a calibrating method for a composite waveplate to be executed,

• A. determining a first matrix characterizing the composite waveplate, the first matrix including at least one unknown number;
• B. determining a theoretical relationship between a light intensity and an alignment angle offset value of the composite waveplate based on the first matrix;
• and
• C. calibrating based on the theoretical relationship between the light intensity and the alignment angle offset value of the composite waveplate determined in step (B) and actually measured light intensity data to obtain a second matrix that characterizes the composite waveplate and does not contain the unknown number.