Reconstructing nanophotonic scattering geometries from their radiation pattern

Work Activities
Lensless imaging and computational imaging are techniques to reconstruct the shape of an object by measuring its diffraction pattern for a diversity of illuminations, as opposed to using imaging optics as one does in a microscope to create a real space image. While it is well understood how to do this for weakly scattering objects, reconstruction becomes very hard for strongly scattering objects, such as encountered in semiconductor metrology. While strong scattering is problematic for general object reconstruction, at the same time you can also use it as a resource: for instance we showed in a recent paper that you can engineer metasurface resonances to boost sensitivity of diffraction patterns to certain geometrical changes [Nat Commun. 16, 11388].

In this project you will push the boundaries of algorithm based reconstruction of nanoscale strongly scattering geometries from their radiation pattern. We seek to develop a physics-based rational approach to optimal parameter reconstruction from diffraction data from designer multiple scattering structures, designed for, e.g., measuring lithography performance in semiconductor manufacturing. The main idea is that you don’t need an algorithm to reconstruct a geometry from scratch, but that you need the algorithm to reconstruct geometry differences relative to a nominal geometry, making full use of physics-based insight, such as the resonant mode structure of the nominal geometry.

In this project you will perform measurements and computational reconstruction hand in hand. On the measurement side, you will use a Fourier microscope where you can measure radiation patterns while cycling through a diversity of illuminating wavefronts that you can generate using a spatial light modulator. On the reconstruction side, you will focus on physics-informed algorithms that use the eigenmode structure of the scattering system for reconstruction (collaboration with JCMwave, Berlin).

Qualifications
You have a MSc degree in physics, optics, photonics, nanoscience, or a related field.

Work environment
AMOLF is a national institute that is part of NWO-I. Its mission is to initiate and perform fundamental research on the physics of complex forms of matter, and to create new functional materials, in partnership with academia and industry. The institute is located at Amsterdam Science Park and currently employs about 140 researchers and 80 support employees. www.amolf.nl

The research activities in the Resonant Nanophotonics group at AMOLF (PI Femius Koenderink) aim at developing nanoscale photonic structures, such as metasurface optics, optical nanoantennas and resonators to control scattering, emission, amplification and detection of light. Our work has applications in the domains of nanophotonic light sources, optical metrology, microscopy, and wavebased information processing.

This project is part of the CHAIN consortium. CHAIN (Coherent Algorith-based Imaging of Nanostructures) brings together experts in optical lensless imaging, electron diffraction, and reconstruction algorithms, and works with industry partners to realize impact in semiconductor metrology, and electron microscopy. The project will involve work discussions and collaboration with the larger team, as well as interaction with industry partners of CHAIN. This project requires a candidate who enjoys working on an industry-relevant topic, and who is eager to learn from other disciplines present in the consortium.

Working conditions

• The working atmosphere at the institute is largely determined by young, enthusiastic, mostly foreign employees. Communication is informal and runs through short lines of communication.
• The position is intended as full-time (40 hours / week, 12 months / year) appointment in the service of the Netherlands Foundation of Scientific Research Institutes (NWO-I) for the duration of four years
• The starting salary is 3.115 Euro’s gross per month and a range of employment benefits.
• After successful completion of the PhD research a PhD degree will be granted at a Dutch University.
• Several courses are offered, specially developed for PhD-students.
• AMOLF assists any new foreign PhD-student with housing and visa applications and compensates their transport costs and furnishing expenses.

More information?
For further information about the position, please contact Femius Koenderink: f.koenderink@amolf.nl and .

Application
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Diversity code
AMOLF is highly committed to an inclusive and diverse work environment: we want to develop talent and creativity by bringing together people from different backgrounds and cultures. We recruit and select on the basis of competencies and talents. We strongly encourage anyone with the right qualifications to apply for the vacancy, regardless of age, gender, origin, sexual orientation or physical ability.

AMOLF has won the NNV Diversity Award 2022, which is awarded every two years by the Netherlands Physical Society for demonstrating the most successful implementation of equality, diversity and inclusion (EDI).

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