Analytical method and apparatus
View Patent ↗A method of examining thin layer structures on a surface for differences in respect of optical thickness, which method comprises the steps of: irradiating the surface with light so that the light is internally or externally reflected at the surface; imaging the reflected light on a first two-dimensional detector; sequentially or continuously scanning the incident angle and/or wavelength of the light over an angular and/or wavelength range; measuring the intensities of light reflected from different parts of the surface and impinging on different parts of the detector, at at least a number of incident angles and/or wavelengths, the intensity of light reflected from each part of the surface for each angle and/or wavelength depending on the optical thickness of the thin layer structure thereon; and determining from the detected light intensities at the different light incident angles and/or wavelengths an optical thickness image of the thin layer structures on the surface. According to the invention, part of the light reflected at said surface is detected on a second detector to determine the incident angle or wavelength of the polarized light irradiating the surface. An apparatus for carrying out the method is also disclosed.
1. A method for analysis of a sensor surface comprising a plurality of individual subzones, which method comprises:
irradiating the sensor surface with a collimated beam of light so that the light is internally or externally reflected at the surface,
imaging reflected light on a first photo-detector such that each subzone of the sensor surface corresponds to a respective area of the detector,
sequentially or continuously scanning the incident angle of the beam of light at the sensor surface over an angular range,
measuring the momentary incident angles of the beam of light by reflecting a part of the beam onto a second photo-detector,
measuring the intensities of light imaged on different areas of the first photo-detector at at least a number of incident angles, and
determining for each subzone of the sensor surface the variation of the intensity of imaged light on the first photo-detector with the incident angle.
2. The method according to claim 1 , wherein the light is totally internally reflected at the sensor surface.
3. The method according to claim 1 , wherein the light is coupled to the sensor surface via a prism.
4. The method according to claim 1 , wherein the light is coupled to the sensor surface via a grating.
5. The method according to claim 1 , wherein the image forming is based on surface plasmon resonance at the sensor surface.