Integrated computational elements with planar waveguide

An optical analysis tool comprising:

• an integrated computational element (ICE) to
• receive, when the tool is operated, light from a sample, and
• process at least a portion of the received light, such that the processed light is related, over a processing wavelength range, comprising wavelengths in a range from about 0.2 μm to about 2.5 μm, to a characteristic of the sample,
• wherein the ICE comprises
• a dispersive optical element comprising
• an input port,
• a substrate and a planar waveguide disposed on the substrate, the planar waveguide to guide light input through the input port, such that the guided light is within an operational wavelength range, comprising wavelengths in a range from about 0.2 μm to about 2.5 μm, that encompasses the processing wavelength range,
• diffractive structures distributed along the planar waveguide to spatially separate the guided light into a plurality of wavelength sub-ranges of the operational wavelength range, wherein a distribution of the diffractive structures is such that the dispersive optical element functions as an ICE core that weights the respective wavelength sub-ranges of the spatially separated light by differing amounts corresponding to the wavelength sub-ranges, the differing amounts being related to the characteristic of the sample, and
• a plurality of output ports to output the spatially separated light of the respective wavelength sub-ranges, wherein
• the diffractive structures comprise lines or grooves etched at an interface between the planar waveguide and an air environment.

An optical analysis tool comprising:

• an integrated computational element (ICE) to
• receive, when the tool is operated, light from a sample, and
• process at least a portion of the received light, such that the processed light is related, over a processing wavelength range, comprising wavelengths in a range from about 0.2 μm to about 2.5 μm, to a characteristic of the sample,
• wherein the ICE comprises
• (I) a dispersive optical element comprising
• an input port,
• a substrate and a planar waveguide disposed on the substrate, the planar waveguide to guide light input through the input port, such that the guided light is within an operational wavelength range, comprising wavelengths in a range from about 0.2 μm to about 2.5 μm, that encompasses the processing wavelength range,
• diffractive structures distributed along the planar waveguide to spatially separate the guided light into a plurality of wavelength sub-ranges of the operational wavelength range, wherein a distribution of the diffractive structures is such that the dispersive optical element functions as a spectrograph that weights the respective wavelength sub-ranges of the spatially separated light by substantially equal amounts, and
• a plurality of output ports to output the spatially separated light of the respective wavelength sub-ranges;
• and
• (II) an ICE core that weights light incident thereof by differing amounts corresponding to the wavelength sub-ranges within the processing wavelength range, the different amounts being related to the characteristic of the sample, and wherein
• the ICE core is optically coupled to the input port of the spectrograph, such that:
• the light input to the input port is sample modified light weighted by the ICE core, and
• the light output at some of the output ports of the spectrograph (i) is the weighted light spatially separated into the respective wavelength sub-ranges within the processing wavelength range and (ii) represents the light processed by the ICE, and
• the optical analysis tool further comprises:
• a multi-element detector to
• receive the processed light from the output ports of the spectrograph, and
• provide a multi-element detector signal corresponding to a spectrum of the processed light, and
• a summing module to:
• integrate the multi-element detector signal, and
• provide an output signal corresponding to a value of the characteristic of the sample, and wherein
• the ICE core comprises
• a substrate having a first surface, wherein the substrate comprises a substrate material with a substrate material refractive index, and
• a plurality of layers stacked on the first surface of the substrate, wherein adjacent ones of the plurality of layers respectively comprise layer materials with refractive indices different from each other, wherein a substrate thickness and thicknesses of the plurality of layers are such that the light weighted by the ICE core is related, over the processing wavelength range, to the characteristic of the sample.

An optical analysis tool comprising:

• an integrated computational element (ICE) to
• receive, when the tool is operated, light from a sample, and
• process at least a portion of the received light, such that the processed light is related, over a processing wavelength range, comprising wavelengths in a range from about 0.2 μm to about 2.5 μm, to a characteristic of the sample,
• wherein the ICE comprises
• (I) a dispersive optical element comprising
• an input port,
• a substrate and a planar waveguide disposed on the substrate, the planar waveguide to guide light input through the input port, such that the guided light is within an operational wavelength range, comprising wavelengths in a range from about 0.2 μm to about 2.5 μm, that encompasses the processing wavelength range,
• diffractive structures distributed along the planar waveguide to spatially separate the guided light into a plurality of wavelength sub-ranges of the operational wavelength range, wherein a distribution of the diffractive structures is such that the dispersive optical element functions as a spectrograph that weights the respective wavelength sub-ranges of the spatially separated light by substantially equal amounts, and
• a plurality of output ports to output the spatially separated light of the respective wavelength sub-ranges;
• and
• (II) an ICE core that weights light incident thereof by differing amounts corresponding to the wavelength sub-ranges within the processing wavelength range, the different amounts being related to the characteristic of the sample, and wherein
• a refractive index of the planar waveguide's material is larger than a refractive index of the substrate's material, and
• the diffractive structures of the dispersive optical element comprise
• a first plurality of refractive index altering features extending along a first direction in a plane of the planar waveguide, and
• a second plurality of refractive index altering features extending along a second direction in the plane, where the second direction is different from the first direction, and
• a width of the refractive index altering features of the first and second pluralities is selected to cause back scattering of light in respective first and second wavelength sub-ranges.