Method for observing an emission of light (14, 15) from a sample (10) in a medium (11) of refractive index n.sub.L disposed against a surface (20a) of a transparent support (20) of refractive index n.sub.s, greater than n.sub.L, the emission of light comprising luminous components oriented toward the support and forming an angle with a direction (20b) perpendicular to the surface (20a), said components including supercritical luminous components and critical or subcritical luminous components, the method implementing an observation device (100) capable of collecting at least part of the emission of light, of applying filters (170) to the luminous signal collected; and of transforming the filtered luminous signal into an image zone of the sample (6a, 6b); the method being characterized in that: A modulation of the filtered luminous signal is carried out, in which luminous components arising from the critical or subcritical luminous components of the emission of light are allowed to pass through so as to obtain image zones (6a, 6b) of one and the same region of interest of the sample, the modulation pertaining to all or some of the luminous components of the collected luminous signal which arise from the supercritical luminous components of the emission of light; and At least one useful image zone (6c) of the sample is produced by combining image zones (6a, 6b), the combination evidencing differences between the image zones (6a, 6b) related to the modulation.

Method for observing an emission of light from a sample in a medium of refractive index nL disposed against a surface of a transparent support of refractive index nS, greater than nL, the emission of light comprising luminous components oriented toward the support and forming an angle and including supercritical luminous components and critical or subcritical luminous components, implementing an observation device applying filters to the signal; and transforming the signal into an image zone of the sample Modulation of the signal is carried out, in which components of the emission of light are allowed to pass through so as to obtain image zones, the modulation pertaining to all or some of the collected signals; and at least one useful image zone of the sample is produced by combining image zones, the combination evidencing differences between the image zones related to the modulation.

An analytical biochip includes a substrate, a lower cladding layer, a waveguide, an upper cladding layer, an emission light collection element and a plurality of nanowells. The lower cladding layer is over the substrate. The waveguide is over the lower cladding layer. The upper cladding layer is over the waveguide. The emission light collection element is over the upper cladding layer, wherein the emission light collection element includes lower protrusion structures extending into the upper cladding layer, and the emission light collection element is made of metal. The nanowells penetrate the emission light collection element and are in the upper cladding layer.