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International audience; Laser microsurgery is the current gold standard surgical technique for the treatment of selected diseases in delicate organs such as the larynx. However, the operations require large surgical expertise and dexterity, and face significant limitations imposed by available technology, such as the requirement for direct line of sight to the surgical field, restricted access, and direct manual control of the surgical instruments. To change this status quo, the European project μRALP pioneered research towards a complete redesign of current laser microsurgery systems, focusing on the development of robotic micro-technologies to enable endoscopic operations. This has fostered awareness and interest in this field, which presents a unique set of needs, requirements and constraints, leading to research and technological developments beyond μRALP and its research consortium. This paper reviews the achievements and key contributions of such research, providing an overview of the current state of the art in robot-assisted endoscopic laser microsurgery. The primary target application considered is phonomicrosurgery, which is a representative use case involving highly challenging microsurgical techniques for the treatment of glottic diseases. The paper starts by presenting the motivations and rationale for endoscopic laser microsurgery, which leads to the introduction of robotics as an enabling technology for improved surgical field accessibility, visualization and management. Then, research goals, achievements, and current state of different technologies that can build-up to an effective robotic system for endoscopic laser microsurgery are presented. This includes research in micro-robotic laser steering, flexible robotic endoscopes, augmented imaging, assistive surgeon-robot interfaces, and cognitive surgical systems. Innovations in each of these areas are shown to provide sizable progress towards more precise, safer and higher quality endoscopic laser microsurgeries. Yet, major impact is really expected from the full integration of such individual contributions into a complete clinical surgical robotic system, as illustrated in the end of this paper with a description of preliminary cadaver trials conducted with the integrated μRALP system. Overall, the contribution of this paper lays in outlining the current state of the art and open challenges in the area of robot-assisted endoscopic laser microsurgery, which has important clinical applications even beyond laryngology.

International audience; Currently, the production of Advanced Therapy Medicinal Products is highly sensitive to any contamination sources and therefore takes place in clean and sterile environments. Several days are required for each production, making these products extremely expensive. Throughout the process, numerous quality controls must be performed. This is especially true during the expansion phase in order to monitor cell growth and to detect any contamination. Bioreactor’s content must periodically be sampled to perform these controls. Two major drawbacks can be identified: a delayed knowledge of the quality control result and an additional risk of new contaminations due to sampling. In this work, we present optical spectroscopy methods which can be used to drastically reduce the risk of contamination. They provide a real time control of what happens in the bioreactor in a closed system manner. Cell concentrations are measured with an accuracy below 5% and contamination can be detected about 3 h after it occurred. The real time operation leads to several tens of thousand dollars’ savings because it allows stopping the production as soon as a problem arises. Consequently, the price of these products should be greatly reduced and they may be proposed to more patients.

International audience; We report Gold/Silica biochips for low cost biosensor devices. Firstly, the study of biochemical interactions on silica by means of Surface Plasmon Resonance (SPR) is presented. Secondly, Gold/Silica biochips are employed to reduce the strong quenching that occurs when a fluorophore is close to the gold surface. Furthermore, the control of the Silica-like thickness allows optimizing the distance between the metallic surface and the fluorophore in order to enhance the fluorescent signal. These results represent the first steps towards highly sensitive, specific and low cost biosensors based, for example, on Surface Plasmon Coupled Emission (SPCE) techniques.

International audience; In blood transfusion, accidents still occur because of ABO mismatch between donor and patient’s blood. These errors, sometimes lethal, are principally due to wrong identification of patient and/or blood product or to human errors. The best way to avoid these errors is to perform an ultimate ABO compatibility test at the patient’s bedside immediately prior to transfusion. Ideally, this test should be performed automatically, without human interpretation and with minimum blood exposure for nurses. This ideal and ultimate method is not yet employed because of the lack of suitable device. In this paper, we propose a system that may fulfil the above mentioned requirements. It is based on selective blood capture on biochip surfaces in a device which automatically drives the different fluids, performs optical detection of captured red cells and finally interprets the optical reading in terms of ABO compatibility. So far, our device achieved blood compatibility test with 99.3 % sensitivity and 97.9 % specificity.

Compensation techniques for producing well defined corner in KOH-etched (1 0 0) silicon have widely been proposed. However, the case of apertures connected with V-grooves has apparently not yet been published. In this paper, we present a compensation technique used in order to produce well defined square apertures connected with V-grooves. A full description of the KOH etching process, simulation methods as well as experimental confirmations are presented here. The technique is very easy to use and is convenient for any size of apertures and V-grooves. The structure obtained with this technique are of interest in many micro-machining domains, especially in the field of micro-fluidics and micro-biology.

International audience; ince rubella vaccine was established, cytomegalovirus infection has become the most frequent cause of congenital infections. The French Health Authority is urging a diagnosis at birth for newborns. Since no screening device is commercially available, a consortium has been established to set-up an original device. The project has been funded by the French National Research Agency. The device consists of a disposable cartridge containing the biological sample and the reactive liquids required for immuno-fluorescencence detection on a functionalized surface. It also consists of a mobile reader used to drive the fluids onto the biosensor and to ensure the optical measurement. Positive and negative samples can be discriminated with a fluorescence intensity ratio of 3.

A Mach–Zehnder unbalanced LiNbO3 integrated modulator with independent control of the phase of each arm is incorporated into the reference arm of a low coherence interferometer set-up. Using different RF modulation frequency and processing electronics tuned to these frequencies, the system can be used for simultaneous interrogation of the signal reflected from two different depths in tissue or from two different axial positions in profilometry. When a pair of XY scanning mirrors are incorporated into the sensing arm, then two en-face images from different axial positions can be simultaneously produced. The depth separation between the axial positions of the points or layers interrogated is equal to half of the modulator path difference. The operation of the system is illustrated by displaying simultaneously two images from a coin.

In this paper, we present a new keying structure which enhances the secrecy of an already relatively secure coherence modulation method we developed recently. The originality of the method consists in using an encrypting key composed of a large amplitude – low frequency part and a low amplitude – high frequency part. These two components ensure that the spectrum, as well as the signal tapped by an eavesdropper, are efficiently corrupted. When the key is applied simultaneously to both the encoder and the decoder, the signal is correctly restored. Both theoretical aspects and experimental confirmations are presented in this paper.

International audience; We report the formation of a 2D waveguide induced by a self-trapped vortex beam in a photorefractive-photovoltaic medium. Demonstrations are performed by monitoring the self-trapping dynamic of an annular vortex beam in a LiNbO(3):Fe crystal. Control of the experimental observations is consistent with the underlying physics revealed by a numerical model.

International audience; The estimation of the a priori maturity degree of oocytes before fertilizing is a critical step in In Vitro Fertilization (IVF). This kind of analysis is currently done by the practitioner with a visual microscope inspection and is therefore subjective. In this paper, we propose the use of an image processing called Karhunen-Loeve Transform (KLT). The KLT exploits the covariance matrix and its eigenvectors for obtaining a representation of information in several images. We show that the KLT permits the determination of the oocyte maturity by examining the KL images and more precisely the eigenvalues of each. The KLT could thus be a useful tool for IVF and we intend to develop a dedicated server for all French IVF centers as a computer aided decision for fertilization.

International audience; The detection of DNA hybridization can be either complicated or require expensive devices. Some methods use a fluorescence signal to investigate hybridization. Here, we present an optical probe based on optical fibers both for illumination and for fluorescence collection. The detection is made with a microspectrophotometer and the signal is then treated with a PC. We also developed the DNA biochips (glass plate with a gold layer functionalized with target DNA) as well as a dedicated microtank which maintains a constant flow of probe DNA over the target one. Finally, the detection of hybridization with this simple and versatile system is presented.

International audience; We present a new combination of a fluorescent film deposited onto a chip and a new kind of lowcost optical fluorescence probe. The probe consists of an optical fiber which guides the excitation beam to the chip and a second one which collects the fluorescence light toward a spectrometer slotted into a PC. The resulting data are then processed to extract the pertinent information. This system is designed for the detection of DNA but, at present, we have achieved the detection of functionalized lipidic vesicles and studied the photobleaching process of such films.

International audience; Compensation techniques for producing well-defined bent V-grooves in KOH etched (1 0 0) silicon have been widely proposed. However, many of the methods presented in the literature suffer from two drawbacks: the etching depth is supposed to be equal to the V-groove depth and the V-groove must be wide enough for the compensation structures to fit in the pattern. A few solutions have been proposed in order to get round these disadvantages, but they are generally complicated to implement. In this paper, we propose a very simple compensation technique to obtain well-defined structures with any arbitrary etching depth and/or V-groove width. The only condition for the compensation is that the V-groove must be long enough.

The sensor is dedicated to the detection of allergens. We use a biochemical reaction in the vicinity of the core of an optical fiber which modifies the propagation conditions of the optical wave by evanescent coupling. The detection involves a intrinsic optical fiber Fabry-Perot interferometer.

In vitro fertilising (IVF) probably belongs to the most exciting subjects of research, not only for human assisted reproduction but also for veterinary medicine. Among the various steps of gamete manipulation, the determination of the cell to be fertilised is perhaps the most critical. Up to now, the choice of the oocyte is made using subjective criteria. It is generally the results of a visual estimation of the morphological properties of the cell. In this paper, we describe our first studies concerning the fabrication of a micro-machined lab-on-chip devoted to the analysis of the cells to be fertilised. The overall idea is to end with a system able to capture the cell on the lab-on-chip surface, to transport it to different analysis stages, and to establish an objective catalogue of the oocyte characteristics. The first issue that must be addressed is capturing, transportating and trapping a single cell at different locations on the chip surface. In this article, we present some of the silicon microsystems used for the capture and the transportation of a single oocyte. We also present a lab-on-chip concept, which exploits the microfluidic technology in order to accurately trap the cell at the desired position.

We present a high-efficiency in-fiber phase modulator, which consists of an annular ZnO piezoelectric transducer deposited on a gold-coated optical fiber by reactive RF planar magnetron sputtering. The deposited film is highly oriented and uniform in thickness and structure, which results in highly efficient acoustooptic interaction in the fiber core. Experimental results show modulator performance significantly exceeding previously reported devices.

We present a study of the effective piezoelectric activity of thin ZnO films produced by radio‐frequency (rf) planar magnetron sputtering. The energetic plasma particles which bombard the substrate in the above deposition system increase the substrate temperature, thus causing a gradual variation in film structure during the beginning of the film growth. As a result, a precursor layer is formed which consists of small randomly oriented crystallites, exhibiting poor piezoelectric activity. Hence, the film thickness responsible for piezoelectric activity is generally less than the physical thickness of the film and is adjacent to a layer having different acoustic impedance. This leads to an increase in the resonant frequency of the film. For example, a film designed to have a half‐wave resonance at 288 MHz, was found to be resonant at 332 MHz. The poorly structured initial layer meant in this typical case that only 87% of this film volume exhibited piezoelectric activity. Investigations based on the substra...

In this paper, we report theoretical and experimental results concerning the upconversion phenomena around 550 nm in Er 3+ -doped Ti:LiNbO 3 waveguides. This phenomena corresponds transitions between the levels 4 S 3/2 implied by 4 I 15/2 . The waveguide is pumped near 980 nm with a laser diode. Two pump photons are used to bring the Er ions to the short lifetime level 4 F 7/2 . After a non-radiative transition to the level 4 S 3/2 , Er ions emit photons at 550 nm while falling down to the 4 I 15/2 level. By using the theoretical model elaborated by McCumber we evaluate the homogeneous emission cross sections and we obtain the following maximum values of the cross sections (sigma) H e (551.9 nm) equals 57.7 x 10 -26 m 2 for TE and (sigma) H e (558.1 nm) equals 52.5 x 10 -26 m 2 for TM polarizations. By measuring the fluorescence radiation around (lambda) equals 550 nm, we determine the rising and falling times and we obtain C equals 0.198 x 10 -23 m 3 /s as the value of the modulus of the homogeneous upconversion factor the value. The results presented here can be used in the design of integrated optoelectronic circuits and in the modeling of the laser action and optical amplification in Er 3+ -doped Ti:LiNbO 3 waveguides when a 980 nm pumping is considered.

Different configurations are presented which allow simultaneous acquisition and presentation of OCT en-face images from different depths. If a sufficient number of slices are collected, 3D rendering of the object in real time is made possible. Results using two configurations to produce simultaneously two such images are presented, as a hardware version towards 3D imaging. Rendering of a 3D profile of the retina is also shown, as a software version, using slices obtained at different depths collected by a single channel en-face OCT instrument.

Recently, with the rapid development of optical telecommunications, a considerable interest as been shown for secure optical transmission. Coding techniques which are not based on intensity modulation can potentially be adapted for secure transmission. Among the different techniques available, the most popular are probably based on frequency1, phase2, coherent correlation3, and coherence modulation4. The coherent schemes employ two interferometers illuminated by a Broadband Source (BBS) with a coherence length shorter than the interferometer’s Optical Path Difference (OPD). Information is encoded by modulating the emitter interferometer’s OPD. The constant optical power transmitted in such systems is attractive for secure communication since, “apparently”, a perfectly matched receiving interferometer is required to decode the signal.

In this presentation, we discuss the security aspect of coherence modulation for telecommunications. Recently, we demonstrated a simple technique for decoding the signal without any decoder interferometer. We now demonstrate a secure alternative method based on the corruption of the interferometer's optical path difference. Experimental results at low bit rate using fiber interferometers as well as transmission at high bit rates using large-imbalanced integrated optic interferometers are presented. Considerations about the polarization state of the light are also discussed.

In this conference, we demonstrate a new communication system exhibiting a double security level. Information coding is based on differential phase shift keying of the light emitted from a highly coherent CW source. An imbalanced Mach-Zehnder interferometer whose time delay matches the bit duration is used to decode the data. Since the optical power is constant in the transmission link, security levels comparable with those obtained in coherence modulation may be achieved. To further enhance the security, a low coherent source is used to send false data down the transmission link. The discrimination between real and false signal is based on common mode rejection. A study of the signal to noise ratio achieved with this system is also discussed in this manuscript.

We report a simple and accurate interferometric method for simultaneous, in situ measurement of both the thickness and the depth resolved optical losses of thin transparent films. The experimental arrangement is simple, requiring only a laser and a detector regardless of the substrate. The originality of our method is based on the evaluation of the optical losses from the envelopes of the laser signal, while the thickness is measured conventionally by counting the number of signal periods. The technique has been tested while growing ZnO films in a planar RF magnetron sputtering system. Using the above method, the evolution of optical losses is easily observed during deposition, leading to the possibility of a real time control of the film quality. Both theoretical calculations and experimental results are presented in this letter.

Summary and Condusions Fibre acousto-optics is capable ofdelivering high performance in-fibre and fibre-compatible components for the control of laser radiation and for use in sensor systems. Components that can be realised include frequency shifters, switches, phase modulators and tunable optical filters. Much can be achieved with silica fibres in spiteoftheir inherently poor M2, and the low phonon energy glasses being developed for long wavelength fibre lasersoffer acoustic performance (measured by M) hundreds oftimes better than silica. Diffractive components basedon gradient-index media present great possibilities for advanced fibre-compatible Bragg cells. The nonplanarhigh-frequency acoustic transducer technology which is essential to the progression of much of bulk and fibreacousto-optics alike is poorly developed and much advantage would be gamed by bringing it to the point whereit was commercially exploitable. 6. AcknowledgementsThe authors would like to acknowledge the support of SERC/DTI under a recent LINK scheme and of the

The paper reviews recent results obtained with wavelength tunable multielectrode lasers and external cavity laser diodes tuned electrically. Potential applications in future systems are also reported, with emphasis put on optical functions such as wavelength switching, bistability and multistability in wavelength.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We describe the fabrication of an intrinsic fiber Fabry-Perot interferometer meant to be used in white light interferometry sensing experiments. It requires the elaboration of a cavity exhibiting a finesse of about 2, and therefore, cavity mirrors with a reflection coefficient of about 23%. The different steps involved in the fabrication of the cavity are addressed. We discuss the optical properties of the e-beam deposited TiO2 and SiO2 multilayer mirrors used for the fabrication of the cavity. In this part, a convenient method for measuring the complex refractive in- dex of the materials is proposed, as well as an in situ monitoring tech- nique used to accurately control the film properties. We next study the evolution of the mirror reflectivity with the splicing procedure, and we propose a modeling of the mirror composition after splicing. Then, the fabrication of a 20-mm-long Fabry-Perot cavity exhibiting a visibility of 0.5 is presented. In this section, an efficient signal processing is pro- posed to reduce any measurement noise. © 2005 Society of Photo-Optical In

A new fiberized fluorescence imaging probe is presented. This device can potentially be used for a wide range of biological or medical applications. By exploiting the chromatic aberrations of gradient index lenses, the excitation blue or near-UV excitation light is focused on the sample surface, while the red fluorescence signal is efficiently launched back to collecting fibers. The excitation fiber is single mode at the working wavelength so that a resolution of 5 microm is obtained over a scanning area of several square millimeters. Experimental fluorescence images are presented. They concern either self-fabricated fluorescent microsamples or views of leaves that constitute an example of biological tissues analysis. The probe can also be adapted for spectroscopic investigations.

International audience; Since rubella vaccine was established, cytomegalovirus (CMV) infection has become the most frequent cause of congenital infections. Before deciding of the benefit of screening in this populations, the French Health Authority (HAS) is urging a diagnosis at birth for newborns. Since no screening device is commercially available, a consortium has been established to set-up an original device. The consortium consists of 3 academic institutions and 2 private companies, and the study has been funded by the French National Research Agency. The device consists of a disposable cartridge containing the biological sample and the reactive liquids required for immunofluorescencence detection on a functionalized surface. It also consists of a mobile reader used to drive the fluids onto the biosensor and to ensure the optical measurement. Up to now, positive and negative samples can be discriminated with a fluorescence intensity ratio of 3.

International audience; This communication describes how fluorescein grafted at the end of an optical fiber can be used for calibration free pH sensing in the range of physiological values. The method is based on a complete mathematical description of the fluorescence mechanisms of this pH indicator. The analysis of the shape of the fluorescence spectra allows computing values of both the pH and the pKa3. Doing this, it becomes possible to access calibration pH sensing using conventional optical fibers. This is, to the best of our knowledge, the first fiber optic calibration free pH sensor reported to date.

International audience; A silicon 3D-array capacitor dedicated for an implantable bradycardia pacemaker is presented. The integrated 3D-shape of the capacitors are designed by fabricating a high ratio micropore array inside the silicon wafer. This special shape enhances the developed surface of the dielectric layer, leading to high capacitance densities, critical for the application in such a biomedical system. The process control, based on nano-characterizations performed on an Atomic Force Microscopy, is deployed for the three major critical fabrication steps: the dielectric conformity, the in-situ phosphorus-doped polycrystalline silicon pore filling and the uniformity of the doping of the electrodes of the SIS capacitor. After the chemical revelation of the deposited dielectric layer, the conformity of the layer and the effectiveness of the filling are proven by AFM topographies. Moreover, the delineation of the electrode doping is examined with the electrical Scanning Capacitance Mode by recording the spatial extension and the carrier concentration. Macroscopic characterisations of the dielectric properties show the stability of the 3D-patterning silicon capacitors concerning the applied voltage and the temperature. Finally, a high integration solution, where the 3D-capacitor are embedded and sandwiched into a multilayer printed circuit board, is exposed by employing thin epoxy laminates prepreg sheets.