Publications by Salma Farahi | EPFL Graph Search

Fluorescence and optical-resolution photoacoustic imaging through capillary waveguides

Demetri Psaltis, Christophe Moser, Salma Farahi, Nicolino Stasio, Emmanuel André Henri Bossy

Endoscopy can be used to obtain high-resolution images at large depths in biological tissues. Usually endoscopic devices have a diameter ranging from 1 to few millimeters. Using digital phase conjugation, it is possible to adapt ultrathin multimode fibers ...

Spie-Int Soc Optical Engineering2016

Minimally Invasive Optical Photoacoustic Endoscopy with a Single Waveguide for Light and Sound

Demetri Psaltis, Ioannis Papadopoulos, Christophe Moser, Salma Farahi, Nicolino Stasio, Emmanuel André Henri Bossy

An endoscopic device for photoacoustic imaging, including a multimode optical fiber having a distal end and a proximal end, a light source to provide a light beam to the proximal end of the multimode optical fiber, a transducer to capture acoustic waves th ...

2016

Methods and apparatus for imaging with multimode optical fibers

Demetri Psaltis, Ioannis Papadopoulos, Christophe Moser, Salma Farahi

A multimode waveguide illuminator and imager relies on a wave front shaping system that acts to compensate for modal scrambling and light dispersion by the multimode waveguide. A first step consists of calibrating the multimode waveguide and a second step ...

2015

Delivery of ultrashort spatially focused pulses through a multimode fiber for two photon endoscopic imaging

Demetri Psaltis, Christophe Moser, Salma Farahi, Edgar Emilio Morales Delgado

Due to their high number of supported modes, multimode optical fibers carry large amount of spatio-temporal information. However, propagation of a light pulse through a multimode optical fiber suffers from spatial distortions due to superposition of the va ...

Spie-Int Soc Optical Engineering2015

Towards new applications using capillary waveguides

Demetri Psaltis, Christophe Moser, Salma Farahi, Nicolino Stasio, Emmanuel André Henri Bossy

In this paper we demonstrate the enhancement of the sensing capabilities of glass capillaries. We exploit their properties as optical and acoustic waveguides to transform them potentially into high resolution minimally invasive endoscopic devices. We show ...

Optical Soc Amer2015

Delivery of an ultrashort spatially focused pulse to the other end of a multimode fiber using digital phase conjugation

Demetri Psaltis, Christophe Moser, Salma Farahi, Edgar Emilio Morales Delgado

Multimode optical fibers potentially allow the transmission of larger amounts of information than their single mode counterparts because of their high number of supported modes. However, propagation of a light pulse through a multimode fiber suffers from s ...

Spie-Int Soc Optical Engineering2015

Digital confocal microscopy through a multimode fiber

Alexandre Goy, Demetri Psaltis, Ioannis Papadopoulos, Christophe Moser, Damien Claude-Marie Loterie, Salma Farahi

Acquiring high-contrast optical images deep inside biological tissues is still a challenging problem. Confocal microscopy is an important tool for biomedical imaging since it improves image quality by rejecting background signals. However, it suffers from ...

Optical Soc Amer2015

Delivery of ultrashort spatially focused pulses through a multimode fiber

Demetri Psaltis, Christophe Moser, Salma Farahi, Edgar Emilio Morales Delgado

Multimode optical fibers potentially allow the transmission of larger amounts of information than their single mode counterparts because of their high number of supported modes. However, propagation of a light pulse through a multimode fiber suffers from s ...

Spie-Int Soc Optical Engineering2015

Complex pattern projection through a multimode fiber

Demetri Psaltis, Christophe Moser, Damien Claude-Marie Loterie, Salma Farahi

Wavefront shaping through multimode fibers has many interesting applications, such as micromanipulation and endoscopy, where the small diameter of fibers is an advantage in terms of miniaturization. However, pattern projection can suffer from deleterious i ...

Spie-Int Soc Optical Engineering2015

Digital confocal microscopy through a multimode fiber

Alexandre Goy, Demetri Psaltis, Ioannis Papadopoulos, Christophe Moser, Damien Claude-Marie Loterie, Salma Farahi

Confocal laser-scanning microscopy is a well-known optical imaging method where a pinhole is used in the illumination and detection pathways of a normal microscope, in order to selectively excite and detect a particular focal volume. The advantage of this ...

Spie-Int Soc Optical Engineering2015

Delivery of focused short pulses through a multimode fiber

Demetri Psaltis, Christophe Moser, Salma Farahi, Edgar Emilio Morales Delgado

Light propagation through multimode fibers suffers from spatial distortions that lead to a scrambled intensity profile. In previous work, the correction of such distortions using various wavefront control methods has been demonstrated in the continuous wav ...

Optical Soc Amer2015

Multi-Scale Modeling Of Photopolymerization For Medical Hydrogel-Implant Design

Dominique Pioletti, Pierre-Etienne Bourban, Andreas Schmocker, Azadeh Khoushabi, Salma Farahi

We report on the modeling of a photopolymerizable hydrogel and its application as a replacement of the interior of the intervertebral disc (so called Nucleus Pulposus). The hydrogel is initially injected in its liquid form and then photopolymerized via a s ...

Spie-Int Soc Optical Engineering2013

Focused light delivery and all optical scanning from a multimode optical fiber using digital phase conjugation

Demetri Psaltis, Christophe Moser, Salma Farahi

We demonstrate a digital phase conjugation technique for generating a sharp focus point at the end of a multimode optical fiber. A sharp focus is experimentally obtained at the distal end of a 200 mu m core multimode fiber. By recording the digital hologra ...

Spie-Int Soc Optical Engineering2013

Dynamic bending compensation while focusing through a multimode fiber

Demetri Psaltis, David Ziegler, Christophe Moser, Salma Farahi

Multimode fiber endoscopes have recently been shown to provide sub-micrometer resolution, however, imaging through a multimode fiber is highly sensitive to bending. Here we describe the implementation of a coherent beacon source placed at the distal tip of ...

Optical Society of America2013

Experimental study of z resolution in acousto-optical coherence tomography using random phase jumps on ultrasound and light

Salma Farahi

Acousto-optical coherence tomography (AOCT) is a variant of acousto-optic imaging (also called ultrasound modulated optical tomography) that makes possible to get resolution along the ultrasound propagation axis z. We present here AOCT experimental results ...

Optical Soc Amer2013

Optical-resolution photoacoustic microscopy by use of a multimode fiber

Demetri Psaltis, Christophe Moser, Salma Farahi, Emmanuel André Henri Bossy

We demonstrate Optical-Resolution Photoacoustic Microscopy (OR-PAM), where the optical field is focused and scanned using Digital Phase Conjugation through a multimode fiber. The focus is scanned across the field of view using digital means, and the acoust ...

American Institute of Physics2013

High-resolution, lensless endoscope based on digital scanning through a multimode optical fiber

Demetri Psaltis, Christophe Moser, Salma Farahi

We propose and experimentally demonstrate an ultra-thin rigid endoscope (450 mu m diameter) based on a passive multimode optical fiber. We use digital phase conjugation to overcome the modal scrambling of the fiber to tightly focus and scan the laser light ...

Optical Soc Amer2013

Increasing the imaging capabilities of multimode fibers by exploiting the properties of highly scattering media

Demetri Psaltis, Christophe Moser, Salma Farahi

We present a design that exploits the focusing properties of scattering media to increase the resolution and the working distance of multimode fiber (MMF)-based imaging devices. Placing a highly scattering medium in front of the distal tip of the MMF enabl ...

Optical Society of America2013

Focusing and scanning light through a multimode optical fiber using digital phase conjugation

Demetri Psaltis, Christophe Moser, Salma Farahi

We demonstrate for the first time to our knowledge a digital phase conjugation technique for generating a sharp focus point at the end of a multimode optical fiber. A sharp focus with a contrast of 1800 is experimentally obtained at the tip of a 105 mu m c ...

2012

Time resolved three-dimensional acousto-optic imaging of thick scattering media

Salma Farahi

Acousto-optic imaging is based on light interaction with focused ultrasound in a scattering medium. Thanks to photorefractive holography combined with pulsed ultrasound, we perform a time-resolved detection of ultrasound-modulated photons in the therapeuti ...

2012