Systems and methods for precise measurement of transparent objects

A measurement system comprising:

• a light source configured to produce a collimated optical beam;
• a modulator configured to modulate the collimated optical beam to produce a collimated modulated optical beam;
• optics configured to direct the collimated modulated optical beam to illuminate a transparent test object;
• a first beam-blocking component including a first aperture positioned between the optics and the test object, the beam-blocking component being configured to allow a portion of the collimated modulated optical beam to travel through the first aperture to illuminate a test region of the test object and to block a remainder of the collimated modulated optical beam from reaching the test object;
• a power detector configured to receive an intensity-modulated optical beam output from the test object and to measure variations in intensity of the intensity-modulated optical beam corresponding to an intensity modulation of the intensity-modulated optical beam, the intensity-modulated optical beam being derived from interaction of the collimated modulated optical beam with the transparent test object;
• and
• a processor coupled to the power detector and configured to produce a representation of variation of thickness of the test object based on the variations in intensity of the intensity-modulated optical beam measured by the power detector.