Published by De Gruyter

Volume 6 Issue 6 - Ptychography / Guest Editors: Andreas Erdmann, Guohai Situ

Issue of Advanced Optical Technologies

Contents
Journal Overview

Publicly Available December 11, 2017

Views

Publicly Available November 30, 2017

Interview: What’s next in lithography?

Andreas Thoss

Page range: 411-412

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Community

Publicly Available December 11, 2017

News from the European Optical Society EOS

Page range: 413-414

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Publicly Available December 6, 2017

Topical issue: Ptychography

Editorial

Publicly Available December 7, 2017

Special issue on ptychography

Andreas Erdmann, Guohai Situ

Page range: 421-422

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Tutorial

November 9, 2017

An introduction to the theory of ptychographic phase retrieval methods

Sander Konijnenberg

Page range: 423-438

Abstract

An overview of several ptychographic phase retrieval methods and the theory behind them is presented. By looking into the theory behind more basic single-intensity pattern phase retrieval methods, a theoretical framework is provided for analyzing ptychographic algorithms. Extensions of ptychographic algorithms that deal with issues such as partial coherence, thick samples, or uncertainties of the probe or probe positions are also discussed. This introduction is intended for scientists and students without prior experience in the field of phase retrieval or ptychography to quickly get introduced to the theory, so that they can put the more specialized literature in context more easily.

Review Articles

December 4, 2017

Coherent diffractive imaging methods for semiconductor manufacturing

Patrick Helfenstein, Iacopo Mochi, Rajendran Rajeev, Sara Fernandez, Yasin Ekinci

Page range: 439-448

Abstract

The paradigm shift of the semiconductor industry moving from deep ultraviolet to extreme ultraviolet lithography (EUVL) brought about new challenges in the fabrication of illumination and projection optics, which constitute one of the core sources of cost of ownership for many of the metrology tools needed in the lithography process. For this reason, lensless imaging techniques based on coherent diffractive imaging started to raise interest in the EUVL community. This paper presents an overview of currently on-going research endeavors that use a number of methods based on lensless imaging with coherent light.

December 11, 2017

Fourier ptychography for high space-bandwidth product microscopy

Liheng Bian, Jinli Suo, Qionghai Dai, Feng Chen

Page range: 449-457

Abstract

Fourier ptychography is a novel imaging technique with high space-bandwidth product (SBP) on the scale of gigapixel, and has been successfully applied for high-resolution and large field-of-view (FOV) microscopy, termed Fourier ptychographic microscopy (FPM). FPM utilizes a low-numerical-aperture objective lens to capture multiple large FOV but low-resolution images under angularly varying illumination, and uses phase-retrieval algorithms to reconstruct the sample’s high-resolution amplitude and phase information. FPM is advantageous over conventional high SBP microscopy techniques in many aspects, including no mechanical scanning, computational acquisition of both amplitude and phase, extended depth of focus, long working distance, and high compatibility with current microscopes. In this paper, we review FPM with its principles, multiple techniques to improve its performance, and its various applications and extensions.

Research Articles

December 4, 2017

Ptychographic imaging with partially coherent plasma EUV sources

Jan Bußmann, Michal Odstrčil, Yusuke Teramoto, Larissa Juschkin

Page range: 459-466

Abstract

We report on high-resolution lens-less imaging experiments based on ptychographic scanning coherent diffractive imaging (CDI) method employing compact plasma sources developed for extreme ultraviolet (EUV) lithography applications. Two kinds of discharge sources were used in our experiments: a hollow-cathode-triggered pinch plasma source operated with oxygen and for the first time a laser-assisted discharge EUV source with a liquid tin target. Ptychographic reconstructions of different samples were achieved by applying constraint relaxation to the algorithm. Our ptychography algorithms can handle low spatial coherence and broadband illumination as well as compensate for the residual background due to plasma radiation in the visible spectral range. Image resolution down to 100 nm is demonstrated even for sparse objects, and it is limited presently by the sample structure contrast and the available coherent photon flux. We could extract material properties by the reconstruction of the complex exit-wave field, gaining additional information compared to electron microscopy or CDI with longer-wavelength high harmonic laser sources. Our results show that compact plasma-based EUV light sources of only partial spatial and temporal coherence can be effectively used for lens-less imaging applications. The reported methods may be applied in combination with reflectometry and scatterometry for high-resolution EUV metrology.

September 11, 2017

Effects of illumination on image reconstruction via Fourier ptychography

Xinrui Cao, Stefan Sinzinger

Page range: 467-474

Abstract

The Fourier ptychographic microscopy (FPM) technique provides high-resolution images by combining a traditional imaging system, e.g. a microscope or a 4f-imaging system, with a multiplexing illumination system, e.g. an LED array and numerical image processing for enhanced image reconstruction. In order to numerically combine images that are captured under varying illumination angles, an iterative phase-retrieval algorithm is often applied. However, in practice, the performance of the FPM algorithm degrades due to the imperfections of the optical system, the image noise caused by the camera, etc. To eliminate the influence of the aberrations of the imaging system, an embedded pupil function recovery (EPRY)-FPM algorithm has been proposed [Opt. Express 22, 4960–4972 (2014)]. In this paper, we study how the performance of FPM and EPRY-FPM algorithms are affected by imperfections of the illumination system using both numerical simulations and experiments. The investigated imperfections include varying and non-uniform intensities, and wavefront aberrations. Our study shows that the aberrations of the illumination system significantly affect the performance of both FPM and EPRY-FPM algorithms. Hence, in practice, aberrations in the illumination system gain significant influence on the resulting image quality.

November 18, 2017

Data compression strategies for ptychographic diffraction imaging

Lars Loetgering, Max Rose, David Treffer, Ivan A. Vartanyants, Axel Rosenhahn, Thomas Wilhein

Page range: 475-483

Abstract

Ptychography is a computational imaging method for solving inverse scattering problems. To date, the high amount of redundancy present in ptychographic data sets requires computer memory that is orders of magnitude larger than the retrieved information. Here, we propose and compare data compression strategies that significantly reduce the amount of data required for wavefield inversion. Information metrics are used to measure the amount of data redundancy present in ptychographic data. Experimental results demonstrate the technique to be memory efficient and stable in the presence of systematic errors such as partial coherence and noise.

December 4, 2017

Measurement of large optical elements used for inertial confinement fusion with ptychography

Xue Dong, Haiyan Wang, Cheng Liu, Hua Tao, Jianqiang Zhu

Page range: 485-491

Abstract

High-power laser drivers are located in huge laser facilities built for inertial confinement fusion, and have achieved important progresses in the past decade; however, many unconventional optical elements implemented still cannot be accurately measured. To solve this problem, the ptychographic iterative engine (PIE), which is a recently developed technique that can detect both the phase and modulus of the light field simultaneously, is adopted to measure the transmission function of these optical elements and then to accurately characterize their key parameters. The distinctive advantage of PIE over other traditional metrology techniques in measuring large optical elements is demonstrated in this paper by detecting the focal length of a lens array and the surface profile of a continuous phase plate.

Research Article

November 8, 2017

Design of pre-optics for laser guide star wavefront sensor for the ELT

Eduard Muslimov, Kjetil Dohlen, Benoit Neichel, Emmanuel Hugot

Page range: 493-499

Abstract

In the present paper, we consider the optical design of a zoom system for the active refocusing in laser guide star wavefront sensors. The system is designed according to the specifications coming from the Extremely Large Telescope (ELT)-HARMONI instrument, the first-light, integral field spectrograph for the European (E)-ELT. The system must provide a refocusing of the laser guide as a function of telescope pointing and large decentring of the incoming beam. The system considers four moving lens groups, each of them being a doublet with one aspherical surface. The advantages and shortcomings of such a solution in terms of the component displacements and complexity of the surfaces are described in detail. It is shown that the system can provide the median value of the residual wavefront error of 13.8–94.3 nm and the maximum value <206 nm, while the exit pupil distortion is 0.26–0.36% for each of the telescope pointing directions.

About this journal

Objective

Advanced Optical Technologies is a strictly peer-reviewed scientific journal. The major aim of Advanced Optical Technologies is to publish recent progress in the fields of optical design, optical engineering, and optical manufacturing. Advanced Optical Technologies has a main focus on applied research and addresses scientists as well as experts in industrial research and development.

Advanced Optical Technologies partners with the European Optical Society (EOS). All its 4.500+ members have free online access to the journal through their EOS member account.

Topics

Optical design
Lithography
Opto-mechanical engineering
Illumination and lighting technology
Precision fabrication
Image sensor devices
Optical materials (polymer based, inorganic, crystalline/amorphous)
Optical instruments in life science (biology, medicine, laboratories)
Optical metrology
Optics in aerospace/defense
Simulation, interdisciplinary
Optics for astronomy
Standards
Consumer optics
Optical coatings

Article formats
Tutorial, Review Article, Research Article, Letter, Short Communication, Views

> Information on submission process

Volume 6 Issue 6 - Ptychography / Guest Editors: Andreas Erdmann, Guohai Situ

Issue of Advanced Optical Technologies

Cover and Frontmatter

Interview: What’s next in lithography?

News from the European Optical Society EOS

News

Special issue on ptychography

An introduction to the theory of ptychographic phase retrieval methods

Abstract

Coherent diffractive imaging methods for semiconductor manufacturing

Abstract

Fourier ptychography for high space-bandwidth product microscopy

Abstract

Ptychographic imaging with partially coherent plasma EUV sources

Abstract

Effects of illumination on image reconstruction via Fourier ptychography

Abstract

Data compression strategies for ptychographic diffraction imaging

Abstract

Measurement of large optical elements used for inertial confinement fusion with ptychography

Abstract

Design of pre-optics for laser guide star wavefront sensor for the ELT

Abstract