Digital Optical Microscopy: Introduction - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Modern Optics Année : 2010

Digital Optical Microscopy: Introduction

Anne Sentenac
  • Fonction : Auteur
  • PersonId : 836364
Kamal Belkebir
  • Fonction : Auteur
  • PersonId : 834041

Résumé

The optical microscope is an invaluable tool for the observation of samples at the micro-scale because of its ease of use and non-invasiveness. Thanks to the action of the lenses on the field diffracted by the sample, it provides instantaneously and analogically a magnified image of the object. The link between this image and the optogeometrical parameters of the object is, however, subtle, so that in most cases, only qualitative information on the sample is obtained. Yet, with the progress in computational power and electromagnetic modelling, it is now possible to consider the microscope images as the input data of an inverse problem. Reconstruction algorithms can be used to retrieve in a quantitative way the sample parameters of interest (such as the permittivity or reflectance maps). (Note that we restrict our attention to imaging approaches that are devoted to non-fluorescent samples.) These techniques, which combine advanced microscopy set-ups with accurate image formation modelling and reconstruction algorithms, are gathered under the generic term of Digital Optical Microscopy. In most works, the sample permittivity is retrieved from one (digital holographic microscopy) or many (tomographic diffractive microscopy) holograms of the object, as discussed in the Tutorial Review by Haeberlé et al. Hence, both the phase and amplitude of the diffracted field are used in the inversion algorithms. This special issue aims at presenting a selection of state of the art studies on this stimulating emerging field of research. It is organised in three main parts. The first part presents experimental realisations of several digital microscopy techniques and modelling of the image formation process. First, different applications and implementations of digital holographic microscopy are presented in Wormald and Coupland. The modelling of image formation when partially coherent light is used is addressed in Langehanenberg et al. and by Mehta et al. for various microscopy set-ups. Then, the performances and experimental realisations of two tomographic diffractive microscopes are discussed in Sarmis et al. and Maire et al. The second part is dedicated to inversion algorithms. Generally, the inversion techniques assume single scattering and are based on inverse Fourier transforms or equivalent direct inversion techniques. Here we present three papers on advanced numerical reconstruction algorithms that account for multiple scattering, take advantage of a priori information (Van den Berg and Abubakar and Ayasso et al.) or use intensity information only (Crocco et al.). The authors of these papers come from the micro-wave community, which is most familiar with digital imaging techniques (because of the lack of lenses in this wavelength range). They bring a fresh perspective on the reconstruction procedures issue. The third part is devoted to studies on advanced digital imaging techniques aiming, for the most part, at improving the resolution beyond the Rayleigh criterion. The interest of polarisation contrast under evanescent illumination for retrieving the sample topography is pointed out experimentally in Yang et al. In Chaumet et al. a tomographic diffractive microscopy experiment in which the object is deposited on a periodically nanostructured substrate is simulated. A linear inversion algorithm adapted to near-field microscopy using broad-band illumination is proposed in Davis et al. Finally, we conclude this special issue with a paper on coherent X-ray imaging technique (Chamard et al.), that shows the commonalities and possible synergy between this lensless imaging technique and digital optical microscopy. We hope that this special issue on digital optical microscopy will convince the reader of the interest of this field of research, which necessitates innovative experimental set-ups, advanced electromagnetic modelling and mathematical research on inversing procedures. We believe that even in optics, where lenses have yielded performing analogical imagers, digital imaging will continue to be a growing success.

Dates et versions

hal-00840236 , version 1 (02-07-2013)

Licence

Paternité - Pas d'utilisation commerciale

Identifiants

Citer

Anne Sentenac, Olivier Haeberlé, Kamal Belkebir. Digital Optical Microscopy: Introduction. Journal of Modern Optics, 2010, 57 (9), pp.685. ⟨10.1080/09500340.2010.498626⟩. ⟨hal-00840236⟩
55 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More