| 摘要 |
<p>The invention relates to a wire-grid biosensor assembly for detecting e.g. particles, beads, or molecules,where the height of the detection volume in the wire-grid can be adjusted by illuminating the wire-grid at angles above the critical angle and controlling the mixture of TE and TM polarized light. The wire-grid is formed on a substrate and has slits with a short axis being smaller than the diffraction limit of the applied radiation and a long axis being larger than the diffraction limit. The wire-grid is irradiated with excitation radiation through the substrate at an angle of incidence larger than the critical angle of the interface between the substrate and a medium that fills the slits. By adjusting a linear polarization state, ?, of the excitation radiation with a polarizer, the height of the detection volume in the slits, or similarly the penetration depth of the evanescent field, can be controlled.</p> |
