OPTICAL CONFIGURATION AND METHOD FOR DIFFERENTIAL REFRACTIVE INDEX MEASUREMENTS

摘要

An optical configuration (210) for differential refractive index measurements of a test sample (TS) relative to a reference sample (RS) comprises an optical path (OP) along which an illumination beam travels to simultaneously illuminate a pair of optical interfaces (230A, 230B) on opposite sides of a meridional plane corresponding to the test sample (TS) and reference sample (RS), respectively. Partial beams leaving the optical interfaces (230A, 230B) are redirected by optical means (240) to illuminate different segments of a linear scanned array (238) aligned in the meridional plane. The difference in location of a pair of shadowlines or a pair of resonance minimums formed by the partial beams on the array (238) provides an indication of the refractive index difference.