Abstract: Method of quantifying an analyte in a liquid medium by means of magnetic particles functionalized by specific ligands of the analyte being quantified, consisting in applying a magnetic field to a liquid medium for a time period several times shorter than that of the reaction between the analyte being quantified and the ligands of the magnetic particles, in measuring the optical density of the liquid medium after applying the magnetic field, in repeating this cycle of applying the magnetic field and of measuring the optical density several times over the duration of the reaction between the analyte and the ligands, in calculating, by extrapolation, a limiting value for the optical density for an infinite magnetic field application time and in deducing therefrom the concentration of the analyte in the liquid medium.

Abstract: Method of quantifying an analyte in a liquid medium by means of magnetic particles functionalized by specific ligands of the analyte being quantified, consisting in applying a magnetic field to a liquid medium for a time period several times shorter than that of the reaction between the analyte being quantified and the ligands of the magnetic particles, in measuring the optical density of the liquid medium after applying the magnetic field, in repeating this cycle of applying the magnetic field and of measuring the optical density several times over the duration of the reaction between the analyte and the ligands, in calculating, by extrapolation, a limiting value for the optical density for an infinite magnetic field application time and in deducing therefrom the concentration of the analyte in the liquid medium.

Abstract: A flat display screen including a.cathode provided with field effect electron emission means, a cathodoluminescent anode placed opposite to the cathode, an extraction grid associated with the cathode, and at least one filtering grid, permeable to electron bombardment and biased to forbid parasitic ions, generated on one side of this filtering grid, to reach the cathode or the anode located on the other side.

Abstract: A polarimeter includes a prism (32) for separating the incident light beam (21) having a Stokes vector (S) into a reflected beam (22) and a transmitted beam (23), the prism not inducing any interferential effect and the transmitted beam being subjected to at least a reflection internal to the prism. The polarimeter also include two final separators (3, 4) for separating respectively each of the reflected beam and the transmitted beam into at least two final beams (25-28), detecting means (5-8) for measuring the intensity levels of the final beams and a processing unit (9) producing the Stokes vector of the light to be measured. Preferably, the reflections internal to the prism (32) are either total reflections, or reflections on a thick absorbing layer. The invention also includes a method for measuring light beam polarization states.

Abstract: An optical component for modulation of polarization, a Mueller polarimeter and ellipsometer containing such an optical component. The optical component modulates a linearly polarized incident beam and returns a modulated beam. It includes a coupled phase modulator which modulates the incident beam twice in succession, the two modulations having the same frequency of &ohgr;/2&pgr;, and a coupling system modifying the polarization state of the light between the two modulations. The ellipsometer includes the means for detection of a measurement beam returned by a sample, which receives the modulated beam, in addition to a processing unit. The means of detection include a polarimeter producing n measured quantities representing the polarization states of the beam, and the processing unit produces m values for each of these quantities by Fourier transform, with n×m≧16 and m≧4, providing simultaneous access to the sixteen components of the Mueller matrix of the sample.