Abstract
We extend coherent diffraction imaging (CDI) to a high numerical aperture reflection mode geometry for the first time. We derive a coordinate transform that allows us to rewrite the recorded far-field scatter pattern from a tilted object as a uniformly spaced Fourier transform. Using this approach, FFTs in standard iterative phase retrieval algorithms can be used to significantly speed up the image reconstruction times. Moreover, we avoid the isolated sample requirement by imaging a pinhole onto the specimen, in a technique termed apertured illumination CDI. By combining the new coordinate transformation with apertured illumination CDI, we demonstrate rapid high numerical aperture imaging of samples illuminated by visible laser light. Finally, we demonstrate future promise for this technique by using high harmonic beams for high numerical aperture reflection mode imaging.
Highlights
The last decade has seen dramatic advances in the development of coherent diffraction imaging (CDI) techniques [1,2,3,4,5,6]
In this paper we demonstrate the most straightforward strategy for reflection mode CDI by illuminating the object with the image of a pinhole, an approach we term apertured illumination CDI (AICDI)
We show for the first time that CDI can image and scan over aperiodic samples in a high numerical aperture (NA), off-axis reflection geometry, demonstrating a versatile reflection-mode microscope
Summary
The last decade has seen dramatic advances in the development of coherent diffraction imaging (CDI) techniques [1,2,3,4,5,6]. Our non-contact technique images a pinhole onto the sample plane, resulting in no damage to the sample and no restriction of the NA of the imaging system, while our advances in the algorithms enable rapid image reconstruction and an ability to correct the diffraction pattern for sample tilt that is inherent to high-NA imaging These advances are important because high-NA reflection mode CDI has many potential applications for example as a nanometrology tool for future generations of semiconductor patterning [31], for dynamic imaging of magnetic domains [14, 32] or catalytic surfaces, and for use when the Received Jun 2012; revised Jul 2012; accepted Jul 2012; published 3 Aug 2012 13 August 2012 / Vol 20, No 17 / OPTICS EXPRESS 19052 sample is thicker than the absorption length of the illuminating light. We make use of this transform to demonstrate reflection-mode CDI using both a HeNe and a high harmonic extreme ultraviolet (EUV) source at a wavelength of 29 nm, with spatial resolutions of 1.4 μm and 100 nm, respectively
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
