# US 2019/0170633 A1 · Cuvette Having High Optical Transmissivity and Method of Forming > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170633 A1 - Document ID: US20190170633A1 - Status: Published application - Kind: A1 - Application number: 16/212,347 - Filed: 2018-12-06 - Published: 2019-06-06 - Earliest claimed: 2017-12-06 - Assignees: California Institute of Technology - Applicants: California Institute of Technology - Inventors: Axel Scherer; Amirhossein Nateghi; Taeyoon Jeon; Frank T. Hartley - Web page: https://patentgrep.com/patent/US20190170633A1 ## CPC - G01N 21/0303: {Optical path conditioning in cuvettes, e.g. windows; adapted optical elements or systems; path modifying or adjustment (G01N21/031 - G01N21/15 take precedence)} - G01N 1/42: Low-temperature sample treatment, e.g. cryofixation - G01N 1/44: Sample treatment involving radiation, e.g. heat - G01N 21/171: {with calorimetric detection, e.g. with thermal lens detection} - G01N 21/255: {Details, e.g. use of specially adapted sources, lighting or optical systems} - G01N 21/35: using infrared light (G01N21/39 takes precedence) - G01N 21/6452: {Individual samples arranged in a regular 2D-array, e.g. multiwell plates} - G01N 21/3504: for analysing gases, e.g. multi-gas analysis - G01N 21/3577: for analysing liquids, e.g. polluted water - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract The present disclosure is directed toward a cuvette for holding a test sample during optical interrogation with a light signal. The transmissivity of the cuvette is increased by a geometric anti-reflection layer disposed on at least one surface of the cuvette, where the geometric anti-reflection layer includes a plurality of geometric features that collectively reduce the reflectivity of the interface between the surface and another medium. As a result, more of the interrogation signal passes through the interface. In some embodiments, every surface through which the interrogation signal passes includes a geometric anti-reflection layer. Due to the increased transmissivity of the cuvette, light detected after passing through it can have an improved signal-to-noise ratio and/or the light signal used to interrogate the sample can have lower intensity. In addition, the reduction of the reflectivity of each surface enables the use of low-cost, high-refractive-index materials, such as conventional silicon. ## Claims ### Claim 1 An optical element comprising a body having: a first wall having a first surface that defines a first plane and a second surface that defines a second plane, wherein the first surface comprises a first material; a second wall having a third surface that defines a third plane and a fourth surface that defines a fourth plane; and a first plurality of features that collectively define a first geometric anti-reflection layer, each feature extending from a first base at the first plane to a tip; wherein the second surface and third surface define at least a portion of a chamber for holding a test sample; wherein a flat surface comprising the first material is characterized by a first reflectivity for a first light signal; and wherein the first geometric anti-reflection layer and the first surface are collectively characterized by a second reflectivity for the first light signal that is lower than the first reflectivity. ### Claim 2 (depends on 1) The optical element of claim 1 further comprising a second plurality of features that collectively define a second geometric anti-reflection layer, each feature of the second plurality thereof extending from a second base at the fourth plane to a second end, wherein the second surface comprises a second material, and wherein a flat surface comprising the second material is characterized by a third reflectivity for the first light signal, and further wherein the second geometric anti-reflection layer and the fourth surface are collectively characterized by a fourth reflectivity for the first light signal that is lower than the third reflectivity. ### Claim 3 (depends on 2) The optical element of claim 2 wherein the first material and second material are the same material. ### Claim 4 (depends on 1) The optical element of claim 1 wherein the first material is silicon. ### Claim 5 (depends on 1) The optical element of claim 1 wherein each feature of the first plurality thereof comprises the first material. ### Claim 6 (depends on 1) The optical element of claim 1 wherein each feature of the first plurality thereof has a sidewall that extends between the first base and the tip, and wherein at least one sidewall of the first plurality thereof includes a surface feature. ### Claim 7 (depends on 1) The optical element of claim 1 further comprising: a second plurality of features that collectively define a second geometric anti-reflection layer, each feature of the second plurality thereof extending from a second base at the second plane to a second end, wherein the second surface comprises the first material, and wherein the second geometric anti-reflection layer and the second surface are collectively characterized by a third reflectivity for the first light signal that is lower than the first reflectivity; and a third plurality of features that collectively define a third geometric anti-reflection layer, each feature of the third plurality thereof extending from a third base at the third plane to a third end, wherein the third surface comprises the first material, and wherein the third geometric anti-reflection layer and the third surface are collectively characterized by a fourth reflectivity for the first light signal that is lower than the first reflectivity. ### Claim 8 (depends on 7) The optical element of claim 7 further comprising a fourth plurality of features that collectively define a fourth geometric anti-reflection layer, each feature of the fourth plurality thereof extending from a fourth base at the fourth plane to a fourth end, wherein the fourth surface comprises the first material, and wherein the fourth geometric anti-reflection layer and the fourth surface are collectively characterized by a fifth reflectivity for the first light signal that is lower than the first reflectivity. ### Claim 9 (depends on 1) The optical element of claim 1 wherein each feature of the first plurality thereof has a cross-section having a lateral dimension that increases monotonically from its tip to its first base. ### Claim 10 (depends on 9) The optical element of claim 9 wherein the monotonic increase is linear. ### Claim 11 (depends on 1) The optical element of claim 1 wherein the first light signal is characterized by a spectral range that extends from a first wavelength to a second wavelength, the first wavelength being shorter than the second wavelength, and wherein the features of the first plurality thereof are separated by an average spacing that is less than the first wavelength. ### Claim 12 (depends on 11) The optical element of claim 11 wherein the first wavelength is 2 microns and the second wavelength is 15 microns. ### Claim 13 An optical element comprising a body that includes: a first wall having a first surface that comprises a first material; and a first plurality of features that collectively define a first geometric anti-reflection layer, each feature extending from a first base at the first plane to a tip; wherein a flat surface comprising the first material is characterized by a first reflectivity for a first light signal; and wherein the first geometric anti-reflection layer and the first surface are collectively characterized by a second reflectivity for the first light signal that is lower than the first reflectivity. ### Claim 14 (depends on 13) The optical element of claim 13 wherein the optical element is a lens. ### Claim 15 (depends on 13) The optical element of claim 13 wherein the first element is a cuvette for holding a test sample, the cuvette comprising a body that includes: the first wall, wherein the first surface defines a first plane, and wherein the first wall includes a second surface that defines a second plane, wherein the second surface comprises the first material; a second wall having a third surface that defines a third plane and a fourth surface that defines a fourth plane, wherein each of the third surface and fourth surface comprises the first material; a first plurality of features that collectively define a first geometric anti-reflection layer, each feature of the first plurality thereof extending from a first base at the first plane to a first tip; a second plurality of features that collectively define a second geometric anti-reflection layer, each feature of the second plurality thereof extending from a second base at the second plane to a second tip; a third plurality of features that collectively define a third geometric anti-reflection layer, each feature of the third plurality thereof extending from a third base at the third plane to a third tip; a fourth plurality of features that collectively define a fourth geometric anti-reflection layer, each feature of the fourth plurality thereof extending from a fourth base at the fourth plane to a fourth tip; wherein the second surface and third surface define at least a portion of a chamber for holding the test sample; wherein a flat surface comprising the first material is characterized by a first reflectivity for a first light signal; wherein the first geometric anti-reflection layer and the first surface are collectively characterized by a second reflectivity for the first light signal, the second geometric anti-reflection layer and the second surface are collectively characterized by a third reflectivity for the first light signal, the third geometric anti-reflection layer and the third surface are collectively characterized by a fourth reflectivity for the first light signal, and the fourth geometric anti-reflection layer and the fourth surface are collectively characterized by a fifth reflectivity for the first light signal; and wherein each of the second, third, fourth, and fifth reflectivities is lower than the first reflectivity. ### Claim 16 (depends on 15) The optical element of claim 15 wherein the features of each of the first, second, third, and fourth pluralities comprise the first material. ### Claim 17 (depends on 16) The optical element of claim 16 wherein the first material is silicon and the first light signal spans a spectral width that includes at least a portion of the mid-infrared spectral range. ### Claim 18 A method for forming an optical element, the method comprising: providing a first substrate having a first surface and a second surface; and forming a first geometric anti-reflection layer that includes a first plurality of features disposed on the first surface such that each of the first plurality of features extends from a first base at the first plane to a tip, wherein the first surface comprises a first material, and wherein a flat surface comprising the first material is characterized by a first reflectivity for a first light signal, and further wherein the first geometric anti-reflection layer and the first surface are collectively characterized by a second reflectivity for the first light signal that is lower than the first reflectivity. ### Claim 19 (depends on 18) The method of claim 18, wherein the optical element is formed as a lens. ### Claim 20 (depends on 18) The method of claim 18, wherein the optical element is formed as a cuvette, and wherein the method further comprises: providing the first substrate such that the first surface defines a first plane and the second surface defines a second plane; providing a second substrate having a third surface that defines a third plane and a fourth surface that defines a fourth plane; and arranging the first substrate and a second substrate such that a second surface and a third surface collectively define at least a portion of a chamber for holding a test sample. ### Claim 21 (depends on 20) The method of claim 20 further comprising forming a first cavity in one of the first and second substrates, wherein the first cavity includes one of the second and third surfaces, and wherein the first and second substrates are arranged by joining the first substrate and second substrate such that the chamber includes the first cavity. ### Claim 22 (depends on 20) The method of claim 20 further comprising: forming a second geometric anti-reflection layer that includes a second plurality of features that are disposed on the fourth surface, each of the second plurality of features extending from a second base at the fourth plane to a second end, wherein the fourth surface comprises a second material, and wherein a flat surface comprising the second material is characterized by a third reflectivity for the first light signal, and wherein the second geometric anti-reflection layer and the fourth surface are collectively characterized by a fourth reflectivity for the first light signal that is lower than the second reflectivity. ### Claim 23 (depends on 20) The cuvette of claim 20 wherein each feature of the first plurality thereof has a cross-section having a lateral dimension that increases monotonically from its tip to its first base. ### Claim 24 (depends on 23) The cuvette of claim 23 wherein the monotonic increase is linear. ### Claim 25 (depends on 20) The method of claim 20 further comprising: forming a second geometric anti-reflection layer that includes a second plurality of features disposed on the second surface, each of the second plurality of features extending from a second base at the second plane to a second end, wherein the second surface comprises the first material and the second geometric anti-reflection layer and the second surface are collectively characterized by a third reflectivity for the first light signal that is lower than the first reflectivity; and forming a third geometric anti-reflection layer that includes a third plurality of features disposed on the third surface, each of the third plurality of features extending from a third base at the third plane to a third end, wherein the third surface comprises the first material and the third geometric anti-reflection layer and the third surface are collectively characterized by a fourth reflectivity for the first light signal that is lower than the first reflectivity. ### Claim 26 (depends on 25) The method of claim 25 further comprising: forming a fourth geometric anti-reflection layer that includes a fourth plurality of features disposed on the fourth surface, each of the fourth plurality of features extending from a fourth base at the fourth plane to a fourth end, wherein the fourth surface comprises the first material, and wherein the fourth geometric anti-reflection layer and the fourth surface are collectively characterized by a fifth reflectivity for the first light signal that is lower than the second reflectivity. ### Claim 27 (depends on 26) The method of claim 26 wherein each of the first, second, third, and fourth plurality of features comprises the first material. ### Claim 28 (depends on 20) The method of claim 20 wherein the first light signal is characterized by a spectral range that extends from a first wavelength to a second wavelength, the first wavelength being shorter than the second wavelength, and wherein the features of the first plurality thereof are separated by an average spacing that is less than the first wavelength. ### Claim 29 (depends on 28) The method of claim 28 wherein the first wavelength is 2 microns and the second wavelength is 15 microns.