Abstract: A photoacoustic detecting device to be applied, via a contact face, against a medium to be analyzed, the device comprising: a hollow cavity; a light source that is pulsed or amplitude-modulated; an acoustic detector configured to detect an acoustic wave extending through the cavity, the device further comprises an interface membrane, forming the contact face, the interface membrane being configured to: form an interface between the gas, filling the cavity, and the medium to be analyzed; block passage of a liquid or gel between the medium to be analyzed and the cavity; and generate an acoustic pressure wave inside the cavity, under the effect of a variation in the temperature of the interface membrane, the temperature variation of the interface membrane being induced by heating of the medium resulting from illumination of the medium.

Abstract: A photoacoustic detecting device comprises a housing which houses: a lighting module, a photoacoustic cell, comprising an surface contact intended to be placed in contact with the medium to analyse, a photoacoustic cavity extending from the surface contact to a top of the photoacoustic cell, at least one window closing the top of the photoacoustic cell or the contact surface of the photoacoustic cell, at least one subwavelength pattern located on a surface of said window, said subwavelength pattern being configured to focus the light beam on an surface of interest of the medium to analyse, a sensor, linked to the cavity, the sensor being configured to detect a generated signal, said generated signal being generated in the photoacoustic cavity by a photothermic effect in the medium, and wherein the photoacoustic cell, the window and the subwavelength pattern are formed on a single silicon wafer.

Abstract: A photoacoustic detecting device comprises a housing which houses: a lighting module, a photoacoustic cell, comprising an surface contact intended to be placed in contact with the medium to analyse, a photoacoustic cavity extending from the surface contact to a top of the photoacoustic cell, at least one window closing the top of the photoacoustic cell or the contact surface of the photoacoustic cell, at least one subwavelength pattern located on a surface of said window, said subwavelength pattern being configured to focus the light beam on an surface of interest of the medium to analyse, a sensor, linked to the cavity, the sensor being configured to detect a generated signal, said generated signal being generated in the photoacoustic cavity by a photothermic effect in the medium, and wherein the photoacoustic cell, the window and the subwavelength pattern are formed on a single silicon wafer.

Abstract: A method for forming glass fibers by a rotary assembly including a shaft rotated about an axis of rotation, a centrifuge secured to the shaft and provided with a primary annular wall including a plurality of primary orifices, and a supply system configured to supply the centrifuge with molten glass, and wherein, under the effect of a centrifugal force resulting from a rotation of the rotary assembly, a primary reserve of glass is formed against the primary annular wall of the centrifuge, the method including a) acquiring, using a camera, of at least one primary image of the centrifuge, b) processing the at least one primary image by an image processing system, and c) evaluating a parameter representative of a volume of the primary reserve by a system for processing the data from the primary image.