Abstract: The invention relates to a biochip comprising a substrate presenting a reflecting main surface and wherein the main surface presents localized sites that are made sensitive to fluorescence detection by a transparent layer having optical thickness (2k+1)?/4 where k is a positive or zero integer and where ? designates a wavelength lying between a wavelength ?0 at which fluorescence is excited and a wavelength ?1 at which fluorescence is emitted. The biochip can be manufactured by depositing a transparent layer of thickness m??/2 on a substrate and by making studs or wells of thickness (2k+1)?/4 in said layer to form said sensitive sites.

Abstract: The invention relates to a biochip comprising a substrate presenting a reflecting main surface and wherein the main surface presents localized sites that are made sensitive to fluorescence detection by a transparent layer having optical thickness (2k+1)&lgr;/4 where k is a positive or zero integer and where &lgr; designates a wavelength lying between a wavelength &lgr;0 at which fluorescence is excited and a wavelength &lgr;1 at which fluorescence is emitted. The biochip can be manufactured by depositing a transparent layer of thickness m&lgr;′/2 on a substrate and by making studs or wells of thickness (2k+1)&lgr;/4 in said layer to form said sensitive sites.