Conference Agenda

Dual and multi-wavelength digital holography has demonstrated to be a relevant tool for desensitized testing of optical surfaces, large deformation of structures or surface shape profiling. With the advent of digital holography, a wide range of applications of dual/multi-wavelength holography was demonstrated, such as endoscopic imaging, calibration of mechanical structures, erosion measurements, in-line industrial inspection, melt-pool monitoring in additive laser welding manufacturing or more recently accurate profiling by coherence scanning profilometry.

However, due to the natural roughness of the inspected surface, speckle decorrelation occurs and noise is included in the data. This noise refers as the “speckle decorrelation” noise. Especially, the noise is non Gaussian, non-stationary, amplitude–dependent and may be anisotropic. In order to yield high quality data for metrology purpose, speckle decorrelation is required to be reduced. Recently deep leaning has emerged as a powerful and rapid approach for processing phase data. This paper proposes an overview of dual and multi-wavelength digital holography approaches and aims at describing the last theoretical results in the analysis of the standard deviation of decorrelation noise. The influence of noise in the measurements of the surface shape is described by an analytical approach. Numerical simulations with realistic experimental parameters are provided and discussed.

Gold standard imaging modalities in biological field are based on fluorescence signals providing high specificity and high resolution. Recently, Fluorescence Microscopy has been combined with microfluidics to develop instrumentations called Imaging Flow Cytometers, high-throughput tools that supply bright-field, darkfield and multiple-channels fluorescence images of each single cell passing in the Field Of View (FOV). Nevertheless, Fluorescence Microscopy has some drawbacks as phototoxicity, photobleaching, expensive costs for sample preparations and also the a-priori knowledge of the tags to be used. For these reasons label-free imaging methods greatly increase in the recent years as the Quantitative Phase Imaging (QPI) technologies for microscopy. One of the optical techniques to achieve QPI is Digital Holography. DH in microscopy has several advantages such as the possibility to numerically scan the focal distance, a properties that open to the integration of DH in microfluidics. Indeed DH combined with microfluidic circuits allows to image particles or cells flowing into the FOV at different depths. Here the capabilities of label-free single-cell imaging by DH are presented and their implications on next future biomedical applications discussed. Static or in-flow configurations combined with DH will be showed describing recent results and perspectives also in combination with Artificial Intelligence architectures.

Traditional methods used to realize the primary standard for the absolute optical power standard rely on expensive equipment and require well-trained personnel for maintenance and measurement activities. Silicon photonics technologies have enabled the development of predictable photodiodes with uncertainty comparable to (or perhaps better than) traditional methods. This work will report these research activities.