Methods and systems for determining optical propertis using low coherence interference signals

Abstract

Methods and related systems for determining properties of optical systems (e.g., interferometers) and/or optical elements (e.g., lenses and/or lens systems) are described. For example, information related to an optical thickness mismatch of an interferometer can be determined by providing scanning interferometry data. The data typically include obtaining one or more interference signals each corresponding to a different spatial location of a test object. A phase is determined for each of multiple frequencies of each interference signal. The information related to the optical thickness mismatch is determined based on the phase for each of the multiple frequencies of the interference signal(s).

1 . A method comprising:
 providing scanning interferometry data from an interferometer, wherein:
 the interferometer comprises multiple optical elements configured to reflect light from a test object different from the optical elements to determine information about the test object, and 
 the scanning interferometry data comprises an interference signal comprising an interference intensity value for each of multiple scan positions of the interferometer; 
   determining a relationship between phase and frequency components of the interference signal; and   reducing, based on the relationship between the phase and frequency components of the interference signal, an optical thickness mismatch for a field position of the interferometer corresponding to the interference signal, the optical thickness mismatch being between the optical elements of a reference arm of the interferometer and the optical elements of a test arm of the interferometer.