PCR-free DNA-based biosensing with polymeric optical hybridization transduction using micro- and submicron-magnetic bead captured on micro-electromagnetic traps

Peer reviewed: NoNRC publication: Ye

Modulated scattering technique in the terahertz domain enabled by current actuated vanadium dioxide switches

The modulated scattering technique is based on the use of reconfigurable electromagnetic scatterers, structures able to scatter and modulate an impinging electromagnetic field in function of a control signal. The modulated scattering technique is used in a wide range of frequencies up to millimeter waves for various applications, such as field mapping of circuits or antennas, radio-frequency identification devices and imaging applications. However, its implementation in the terahertz domain remains challenging. Here, we describe the design and experimental demonstration of the modulated scattering technique at terahertz frequencies. We characterize a modulated scatterer consisting in a bowtie antenna loaded with a vanadium dioxide switch, actuated using a continuous current. The modulated scatterer behavior is demonstrated using a time domain terahertz spectroscopy setup and shows significant signal strength well above 0.5 THz, which makes this device a promising candidate for the development of fast and energy-efficient THz communication devices and imaging systems. Moreover, our experiments allowed us to verify the operation of a single micro-meter sized VO2 switch at terahertz frequencies, thanks to the coupling provided by the antenna

Ultrafast Laser-Based Spectroscopy and Sensing: Applications in LIBS, CARS, and THz Spectroscopy

Ultrafast pulsed lasers find application in a range of spectroscopy and sensing techniques including laser induced breakdown spectroscopy (LIBS), coherent Raman spectroscopy, and terahertz (THz) spectroscopy. Whether based on absorption or emission processes, the characteristics of these techniques are heavily influenced by the use of ultrafast pulses in the signal generation process. Depending on the energy of the pulses used, the essential laser interaction process can primarily involve lattice vibrations, molecular rotations, or a combination of excited states produced by laser heating. While some of these techniques are currently confined to sensing at close ranges, others can be implemented for remote spectroscopic sensing owing principally to the laser pulse duration. We present a review of ultrafast laser-based spectroscopy techniques and discuss the use of these techniques to current and potential chemical and environmental sensing applications

French decorative and industrial arts : the Beauvais manufacture and its painters during the second half of the nineteenth century

Entre 1848 et 1914, un groupe de peintres exerça une « mainmise » sur la Manufacture de Beauvais. Pierre-Adolphe Badin et son fils, Jules, Pierre-Adrien Chabal-Dussurgey et Jules Diéterle en furent tour à tour les administrateurs et les principaux cartonniers. Chacun était issu d’une formation différente, de la plus courue à la moins reconnue : des Beaux-arts de Paris à l’école de l’industrie. Malgré la diversité de leur parcours, la Révolution de 1848 les rassembla au sein des Manufactures nationales, où ils participèrent à la régénération des arts décoratifs français. Il s’agit de comprendre les choix esthétiques de la Manufacture à travers deux niveaux d’analyse : celui des individus et de leur réseau, en les resituant ensuite dans le contexte plus général de l’industrie textile de la seconde moitié du XIXe siècle.Between 1848 and 1914, a group of painters had a “stranglehold” on the Beauvais tapestry Manufacture. Pierre-Adolphe Badin and his son, Jules, Pierre-Adrien Chabal-Dussurgey and Jules Diéterle were in turns the managers and the main cartoon painters of this manufacture. They all came from different backgrounds: two of them attended the Fine Arts School of Paris, while the others ones were trained in the industry. Despite the diversity of their artistic careers, the French Revolution of 1848 brought these painters together within the National Manufactories, where they contributed to the revival of the French decorative arts. The aesthetic choices of the Beauvais Manufacture will be analyzed through the lens of these individual people and their network, while taking into account the global context of the textile industry during the second half of the nineteenth century

Fast three-dimensional nanostructure fabrication by laser-assisted nanotransfer printing

The authors present a laser-assisted nanotransfer printing technique for transferring metal nanopatterns onto prepatterned substrates. A fused quartz mold covered with an array of chromium nanodots is pressed against the surface of a photolithographically patterned substrate, while a single laser pulse from a quadrupled-frequency solid state Nd:YAG laser is used to melt the thin metal structures. By controlling the laser fluence, selective metal pattern transfer can be realized only on the protruded area of the substrate upon separation of the quartz support. The transferred chromium nanodots are then used as an etch mask to pattern three-dimensional structures.Peer reviewed: YesNRC publication: Ye

Dynamics of superparamagnetic and ferromagnetic nano-objects in continuous-flow microfluidic devices

We present a numerical study on the dynamics of magnetic micro- and nano-objects subjected to magnetic field gradients in conventional continuous-flow microfluidic devices. By a mixed finite-element/discrete-element approach we solve the equations of the field driven motion for magnetic nano-objects floating in liquids at very low Reynolds numbers and compare the magnetic trapping efficiency of commercially available superparamagnetic microbeads to that of ferromagnetic nanowires. The drag force and the remanent magnetization of ferromagnetic nanowires are found to be responsible for the huge increase of their magnetic trappability whereas the slip-length associated with the Navier boundary condition at the transition to the nanoscale regime is found to be a much less important parameter.Peer reviewed: YesNRC publication: Ye

The influence of magnetic carrier size on the performance of microfluidic integrated micro-electromagnetic traps

Efficient manipulation and capture of magnetic carriers in fluid stream require appropriate magnetic confinement devices whose performances are strongly dependent on the nature of the magnetic carriers. In this sense, we have performed a systematic investigation of the magnetic capture efficiencies for five commercially available superparamagnetic particles pumped along rectangular microfluidic channels using microelectromagnetic traps composed of planar circular current-carrying microwires and cylindrical ferromagnetic posts. In addition, in order to obtain a quantitative description of particle movement, we have implemented a numerical model for the dynamics of magnetic objects subjected to magnetic field gradients in conventional continuous-flow microfluidic devices. Fully 3D trajectories of the particles, effective cross-sectional areas of the microchannel as well as micro-electromagnet trapping efficiencies are compared to experimental measurements and a very good agreement is obtained. Finally, a simple and effective analytical model to determine the critical velocity, i.e. when the magnetic trapping device is no longer able to capture and hold 100% of the magnetic superparamagnetic particles, is also presented.Peer reviewed: YesNRC publication: Ye