Interferometric optical systems having simultaneously scanned optical path length and focus

US7012700B2 · kind B2 · utility

Assignee

• Zygo Corporation · US

Inventors

• Peter De Groot · Middletown, US
• Xavier Colonna De Lega · Middletown, US
• Senthil Balasubramaniam · Rocky Hill, US

Key dates

• Filing date: Jun 17, 2003
• Grant date: Mar 14, 2006
• Expiry date: Oct 6, 2023

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B9/0209
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In certain aspects, the invention features scanning interferometry systems and methods that can scan an optical measurement surface over distances greater than a depth of focus of imaging optics in the interferometry system, while keeping an optical measurement surface in focus (i.e., maintaining an image of the optical measurement surface coincident with the detector). The optical measurement surface refers to a theoretical test surface in the path of test light in the interferometer that would reflect the test light to produce an optical path length difference (OPD) between it and reference light that is equal to a constant across a detector.