Metrology of a Focusing Capillary Using Optical Ptychography

• Main Authors: Xiaojing Huang, Evgeny Nazaretski, Weihe Xu, Dean Hidas, Mark Cordier, Benjamin Stripe, Wenbing Yun, Yong S. Chu
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Sensors
• Subjects: X-ray capillary optics; X-ray microscopy; ptychography
• Online Access: https://www.mdpi.com/1424-8220/20/22/6462
• ISSN: 1424-8220

The focusing property of an ellipsoidal monocapillary has been characterized using the ptychography method with a 405 nm laser beam. The recovered wavefront gives a <inline-formula><math display="inline"><semantics><mrow><mn>12.5</mn><mo>×</mo><mn>10.4</mn></mrow></semantics></math></inline-formula><inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>m<inline-formula><math display="inline"><semantics><msup><mrow></mrow><mn>2</mn></msup></semantics></math></inline-formula> focus. The reconstructed phase profile of the focused beam can be used to estimate the height error of the capillary surface. The obtained height error shows a Gaussian distribution with a standard deviation of 1.3 <inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">μ</mi></semantics></math></inline-formula>m. This approach can be used as a quantitative tool for evaluating the inner functional surfaces of reflective optics, complementary to conventional metrology methods.