Method and apparatus for determination of refractive index

A method for determining the interaction of a solute in a liquid or a gaseous sample with a surface comprising

• i) providing a measuring waveguide resonator, which comprises an open waveguide and a closed waveguide, wherein said closed waveguide comprises a contact area including a surface layer that specifically binds a component of a gaseous or of a liquid sample, thereby changing the refractive index of said surface layer, and wherein said change in refractive index of the surface layer results in a change in the resonance wavelength of the closed waveguide and wherein said closed waveguide is positioned adjacent to said open waveguide so as to couple to said open waveguide;
• ii) coupling light from a light source into one end of the open waveguide;
• and
• iii) measuring the change in the resonance wavelength of said closed waveguide caused by the presence of said sample to determine the interaction of a solute in said liquid or gaseous sample with said surface layer.

A method for measuring the concentration of a solute in a liquid or gaseous sample, comprising

• i) providing a waveguide resonator, which comprises an open waveguide and a closed waveguide, said waveguides being adjacent to each other so as to allow their coupling, and a means for positioning a sample proximal to said closed waveguide so that the presence of said sample can change the effective refractive index of said closed waveguide;
• ii) coupling light from a light source into one end of the open waveguide;
• iii) introducing a sample containing said solute into said sample-positioning means;
• iv) measuring the resonance wavelength or change in resonance wavelength of said closed waveguide caused by the presence of said sample;
• and
• v) determining the concentration of said solute by comparing the resonance wavelength or change in resonance wavelength measured in step iv) to a calibration curve that relates concentration of said solute to said resonance wavelength or change in resonance wavelength.

A method for measuring the concentration of a solute in a liquid or gaseous sample through a surface interaction, comprising

• i) providing a measuring waveguide resonator, which comprises an open waveguide and a closed waveguide, said waveguides being adjacent to each other so as to allow their coupling, and a means for positioning a sample proximal to said closed waveguide so that the presence of said sample can change the effective refractive index of said closed waveguide;
• ii) coupling light from a light source into one end of the open waveguide;
• and
• iii) measuring the resonance wavelength of said closed waveguide caused by the presence of said sample;
• wherein said closed waveguide comprises a contact area including a surface layer that specifically binds a component of a gaseous or of a liquid sample thereby changing the refractive index of said surface layer, and wherein said change in refractive index of the surface layer results in a change in the resonance wavelength of the closed waveguide;
• and
• iv) determining the concentration of said solute by comparing the resonance wavelength or change in resonance wavelength measured in step iii) to a calibration curve that relates concentration of said solute to said resonance wavelength or change in resonance wavelength.

A device for measuring the refractive index of a gaseous, liquid or solid sample, comprising

• a measuring waveguide resonator comprising an open waveguide, a closed waveguide, and a sample positioning means,
• wherein said closed waveguide is positioned adjacent to said open waveguide so as to couple to said open waveguide and wherein said sample positioning means is operatively connected to said closed waveguide so that the presence of a sample within said sample positioning means can result in a change in the resonance wavelength of said closed waveguide;
• a light source;
• means for coupling light from said light source into one end of the open waveguide;
• and
• means for detecting light transmitted by the open waveguide.

A device for measuring a refractive index change carried by binding of a component of a gaseous or liquid sample to a surface layer, comprising

• a measuring waveguide resonator comprising an open waveguide and a closed waveguide;
• wherein said closed waveguide comprises at least one contact area including a surface layer that specifically binds a component of a gaseous or of a liquid sample, thereby changing the refractive index of said surface layer, and wherein said change in refractive index of the surface layer results in a change in the resonance wavelength of the closed waveguide and wherein said closed waveguide is positioned adjacent to said open waveguide so as to couple to said open waveguide;
• a light source.;
• means for coupling light from said light source into one end of the open waveguide;
• and
• means for detecting light transmitted by the open waveguide.

A method for determining the refractive index of a gaseous, liquid or solid sample, comprising:

• i) providing a measuring waveguide resonator, which comprises an open waveguide and a first closed waveguide, said waveguides being adjacent to each other so as to allow their coupling, and a means for positioning a sample proximal to said first closed waveguide so that the presence of said sample can change the effective refractive index of said first closed waveguide;
• ii) providing a reference waveguide resonator, which comprises an open waveguide, which can be the open waveguide of the measuring waveguide resonator or a separate open waveguide, and a second closed waveguide, said second waveguide being adjacent to said open waveguide so as to allow their coupling, and wherein said second closed waveguide is of sufficient size as to give rise to a large number of resonances;
• iii) coupling light from a tunable laser into one end of the open waveguide of said measuring waveguide resonator and into one end of said reference waveguide resonator;
• iv) determining the current-wavelength characteristic of the laser on the basis of variations in the mutual distance between the resonances of the reference waveguide resonator;
• v) calibrating the wavelength of the laser on the basis of the current-wavelength characteristic determined in step iv);
• and
• vi) measuring the change in the resonance wavelength of the first closed waveguide of said measuring waveguide resonator caused by the presence of said sample.

A method for determining the interaction of a solute in a liquid or a gaseous sample with a surface comprising

• i) providing a measuring waveguide resonator, which comprises an open waveguide and a closed waveguide, said waveguides being adjacent to each other so as to allow their coupling, and a means for positioning a sample proximal to said closed waveguide so that the presence of said sample can change the effective refractive index of said closed waveguide;
• ii) providing a reference waveguide resonator, which comprises an open waveguide, which can be the open waveguide of the measuring waveguide resonator or a separate open waveguide, and a second closed waveguide, said second waveguide being adjacent to said open waveguide so as to allow their coupling, and wherein said second closed waveguide is of sufficient size as to give rise to a large number of resonances;
• iii) coupling light from a tunable laser into one end of the open waveguide of said measuring waveguide resonator and into one end of said reference waveguide resonator;
• iv) determining the current-wavelength characteristic of the laser on the basis of variations in the mutual distance between the resonances of the reference waveguide resonator;
• v) calibrating the wavelength of the laser on the basis of the current-wavelength characteristic determined in step iv);
• and
• vi) measuring the change in the resonance wavelength of the first closed waveguide of said measuring waveguide resonator caused by the presence of said sample.

A method for measuring the concentration of a solute in a liquid or gaseous sample through interaction with a surface, comprising

• i) providing a waveguide resonator, which comprises an open waveguide and a closed waveguide, wherein said closed waveguide comprises at least one contact area including a surface layer that specifically binds a component of a gaseous or of a liquid sample, thereby changing the refractive index of said surface layer, and wherein said change in refractive index of the surface layer results in a change in the resonance wavelength of the closed waveguide and wherein said closed waveguide is positioned adjacent to said open waveguide so as to couple to said open waveguide;
• ii) providing a reference waveguide resonator, which comprises an open waveguide, which can be the open waveguide of the measuring waveguide resonator or a separate open waveguide, and a second closed waveguide, said second waveguide being adjacent to said open waveguide so as to allow their coupling, and wherein said second closed waveguide is of sufficient size as to give rise to a large number of resonances;
• iii) coupling light from a tunable laser into one end of the open waveguide of said measuring waveguide resonator and into one end of said reference waveguide resonator;
• iv) determining the current-wavelength characteristic of the laser on the basis of variations in the mutual distance between the resonances of the reference waveguide resonator;
• v) calibrating the wavelength of the laser on the basis of the current-wavelength characteristic determined in step iv);
• vi) measuring the change in the resonance wavelength of the first closed waveguide of said measuring waveguide resonator caused by the presence of said sample;
• and
• vii) determining the concentration of said solute by comparing the resonance wavelength change measured in step vi) to a calibration curve that relates concentration of said solute to said change in resonance wavelength.

A method for measuring concentration of a solute in a liquid or gaseous sample, comprising

• i) providing a measuring waveguide resonator, which comprises an open waveguide and a closed waveguide, said waveguides being adjacent to each other so as to allow their coupling, and a means for positioning a sample proximal to said closed waveguide so that the presence of said sample can change the effective refractive index of said closed waveguide;
• ii) providing a reference waveguide resonator, which comprises an open waveguide, which can be the open waveguide of the measuring waveguide resonator or a separate open waveguide, and a second closed waveguide, said second waveguide being adjacent to said open waveguide so as to allow their coupling, and wherein said second closed waveguide is of sufficient size as to give rise to a large number of resonances;
• iii) coupling light from a tunable laser into one end of the open waveguide of said measuring waveguide resonator and into one end of said reference waveguide resonator;
• iv) determining the current-wavelength characteristic of the laser on the basis of variations in the mutual distance between the resonances of the reference waveguide resonator;
• v) calibrating the wavelength of the laser on the basis of the current-wavelength characteristic determined in step iv);
• vi) measuring the change in the resonance wavelength of the first closed waveguide of said measuring waveguide resonator caused by the presence of said sample;
• and
• vii) determining the concentration of said solute by comparing the resonance wavelength change measured in step vi) to a calibration curve that relates concentration of said solute to said change in resonance wavelength.