Pages
- 1
- 2
- document
-
Chang, J. (author), Los, Johannes W.N. (author), Gourgues, Ronan (author), Steinhauer, Stephan (author), Dorenbos, S.N. (author), Pereira, S.F. (author), Urbach, Paul (author), Zwiller, Val (author), Esmaeil Zadeh, I.Z. (author)Shortly after their inception, superconducting nanowire single-photon detectors (SNSPDs) became the leading quantum light detection technology. With the capability of detecting single-photons with near-unity efficiency, high time resolution, low dark count rate, and fast recovery time, SNSPDs outperform conventional single-photon detection...journal article 2022
- document
-
Chang, J. (author), Los, J. W.N. (author), Tenorio Pearl, J.O. (author), Noordzij, N. (author), Gourgues, R.B.M. (author), Guardiani, A. (author), Zichi, J. R. (author), Pereira, S.F. (author), Urbach, Paul (author), Zwiller, V. (author), Dorenbos, S.N. (author), Esmaeil Zadeh, I.Z. (author)Single photon detectors are indispensable tools in optics, from fundamental measurements to quantum information processing. The ability of superconducting nanowire single photon detectors (SNSPDs) to detect single photons with unprecedented efficiency, short dead time, and high time resolution over a large frequency range enabled major...journal article 2021
- document
-
Dou, X. (author), Pereira, S.F. (author), Min, Changjun (author), Zhang, Yuquan (author), Meng, P. (author), Urbach, Paul (author), Yuan, Xiaocong (author)The sidewall angle (SWA) of a nanostructure exerts influence on the performance of the nanostructure and plays an important role in processing nano-structural chips. It is still a great challenge to determine steep SWAs from far field measurements especially when the SWAs are close to 90°. Here, we propose a far-field detection system to...journal article 2021
- document
-
Meng, P. (author), Pham, Hong Liên (author), Pereira, S.F. (author), Urbach, Paul (author)Lateral resolution enhancement is demonstrated in a confocal imaging system with amplitude-modulated radially polarized (RP) light at the wavelength Annular pupil fields and optimized amplitude distribution functions can be realized with a spatial light modulator. By comparing images obtained with full and amplitude modulated apertures of RP...journal article 2020
- document
-
Kolenov, D. (author), Urbach, Paul (author), Pereira, S.F. (author)We demonstrate the far field detection of low-contrast nanoparticles on surfaces using a technique that is based on evanescent-wave amplification due to a thin dielectric layer that is deposited on the substrate. This research builds upon earlier results where scattering enhancement of 200 nm polystyrene (PSL) particles on top of a glass...journal article 2020
- document
-
Meng, P. (author), Pereira, S.F. (author), Dou, X. (author), Urbach, Paul (author)Improving the image quality of small particles is a classic problem and especially challenging when the distance between particles are below the optical diffraction limit. We propose a imaging system illuminated with radially polarized light combined with a suitable substrate that contains a thin dielectric layer to demonstrate that the...journal article 2020
- document
-
Chang, J. (author), Esmaeil Zadeh, I.Z. (author), Los, Johannes W.N. (author), Zichi, Julien (author), Fognini, Andreas (author), Gevers, Monique (author), Dorenbos, Sander (author), Pereira, S.F. (author), Urbach, Paul (author), Zwiller, Val (author)In the past decade, superconducting nanowire single-photon detectors (SNSPDs) have gradually become an indispensable part of any demanding quantum optics experiment. Until now, most SNSPDs have been coupled to single-mode fibers. SNSPDs coupled to multimode fibers have shown promising efficiencies but have yet to achieve high time resolution....journal article 2019
- document
-
Dwivedi, P. (author), Konijnenberg, A.P. (author), Pereira, S.F. (author), Meisner, J.A. (author), Urbach, Paul (author)Ptychography is a form of coherent diffractive imaging; it employs far-field intensity patterns of the object to reconstruct the object. In ptychography, an important limiting factor for the reconstructed image quality is the uncertainty in the probe positions. Here, we propose a new approach which uses the hybrid input-output algorithm and...journal article 2019
- document
-
Dwivedi, P. (author), Pereira, S.F. (author), Urbach, Paul (author)Wavefront aberration measurements are required to test an extreme ultraviolet (EUV) imaging system. For a high-NA EUV imaging system, where conventional wavefront-sensing techniques show limitations, ptychography can be used for this purpose. However, at the wavelength region of EUV (i.e., 13.5 nm), the position accuracy of the scanning mask...journal article 2019
- document
-
Dwivedi, P. (author), Konijnenberg, A.P. (author), Pereira, S.F. (author), Urbach, Paul (author)Ptychography, a form of Coherent Diffractive Imaging, is used with short wavelengths (e.g. X-rays, electron beams) to achieve high-resolution image reconstructions. One of the limiting factors for the reconstruction quality is the accurate knowledge of the illumination probe positions. Recently, many advances have been made to relax the...journal article 2018
- document
-
Meng, P. (author), Pereira, S.F. (author), Urbach, Paul (author)Rigorous vectorial focusing theory is used to study the imaging of small adjacent particles with a confocal laser scanning system. We consider radially polarized illumination with an optimized amplitude distribution and an annular lens to obtain a narrower distribution of the longitudinal component of the field in focus. A polarization...journal article 2018
- document
-
Xu, Xiaosi (author), Konijnenberg, A.P. (author), Pereira, S.F. (author), Urbach, Paul (author)Coherent Fourier scatterometry is an optical metrology technique that utilizes the measured intensity of the scattered optical field to reconstruct certain parameters of test structures written on a wafer with nano-scale accuracy. The intensity of the scattered field is recorded with a camera and this information is used to retrieve the...journal article 2017
- document
-
Roy, S. (author), Pereira, S.F. (author), Urbach, Paul (author), Wei, X. (author), El Gawhary, O. (author)The classical problem of subwavelength particle detection on a flat surface is especially challenging when the refractive index of the particle is close to that of the substrate. We demonstrate a method to improve the detection ability several times for such a situation, by enhancing the "forbidden" evanescent waves in the substrate using the...journal article 2017
- document
-
Ezerskaia, A. (author), Ras, Arno (author), Bloemen, Pascal (author), Pereira, S.F. (author), Urbach, Paul (author), Varghese, Babu (author)We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between specular and diffuse reflection and on the other on...journal article 2017
- document
-
Konijnenberg, A.P. (author), Coene, W.M.J.M. (author), Pereira, S.F. (author), Urbach, Paul (author)In this article we combine the well-known Ptychographical Iterative Engine (PIE) with the Hybrid Input-Output (HIO) algorithm. The important insight is that the HIO feedback function should be kept strictly separate from the reconstructed object, which is done by introducing a separate feedback function per probe position. We have also...journal article 2016
- document
-
Ushakova, K. (author), Van den Berg, Q.Y. (author), Pereira, S.F. (author), Urbach, H.P. (author)Spot size reduction is demonstrated by printing focused spots from amplitude-modulated radially polarized light at the wavelength ? = 405 nm on a photoresist. Amplitude modulation is realized by ring illumination and by application of an optimized amplitude distribution function. Amplitude modulation is implemented via spatial light modulator,...journal article 2015
- document
-
Roy, S. (author), Ushakova, K. (author), Van den Berg, Q. (author), Pereira, S.F. (author), Urbach, H.P. (author)A fast noninvasive method based on scattering from a focused radially polarized light to detect and localize subwavelength nanoparticles on a substrate is presented. The technique relies on polarization matching in the far field between scattered and spurious reflected fields. Results show a localization uncertainty of ?10?4?2 is possible for a...journal article 2015
- document
-
Roy, S. (author), Assafrao, A.C. (author), Pereira, S.F. (author), Urbach, H.P. (author)Inspection tools for nano-particle contamination on a planar substrate surface is a critical problem in micro-electronics. The present solutions are either expensive and slow or inexpensive and fast but have low sensitivity because of limitations due to diffraction. Most of them are also substrate specific. In this article we report how Coherent...journal article 2014
- document
-
Konijnenberg, A.P. (author), Wei, L. (author), Kumar, N. (author), Couto Correa Pinto Filho, L. (author), Cisotto, L. (author), Pereira, S.F. (author), Urbach, H.P. (author)In several optical systems, a specific Point Spread Function (PSF) needs to be generated. This can be achieved by shaping the complex field at the pupil. The Extended Nijboer-Zernike (ENZ) theory relates complex Zernike modes on the pupil directly to functions in the focal region. In this paper, we introduce a method to engineer a PSF using the...journal article 2014
- document
-
Haber, A. (author), Polo, A. (author), Maj, I. (author), Pereira, S.F. (author), Urbach, H.P. (author), Verhagen, M.H.G. (author)In this paper we experimentally demonstrate the proof of concept for predictive control of thermally induced wavefront aberrations in optical systems. On the basis of the model of thermally induced wavefront aberrations and using only past wavefront measurements, the proposed adaptive optics controller is able to predict and to compensate the...journal article 2013
Pages
- 1
- 2