# US 2026/0092829 A1 · Optical leak detection in liquid cooling systems using holographic optical element > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0092829 A1 - Document ID: US20260092829A1 - Status: Published application - Kind: A1 - Application number: 18/900,761 - Filed: 2024-09-29 - Published: 2026-04-02 - Earliest claimed: 2024-09-29 - Assignees: Dell Products L.P. - Applicants: Dell Products L.P. - Inventors: James L. Petivan, III; Sandor Farkas - Web page: https://patentgrep.com/patent/US20260092829A1 ## CPC - G01M 3/38: by using light (G01M3/02 takes precedence) - H05K 7/20272: {Accessories for moving fluid, for expanding fluid, for connecting fluid conduits, for distributing fluid, for removing gas or for preventing leakage, e.g. pumps, tanks or manifolds} - H05K 7/20772: {within server blades for removing heat from heat source} - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract An apparatus includes a holographic optical element (HOE) and an optical sensor. The HOE is configured to have an interference pattern that functions as mirrors in an inverted server when illuminated by a light source. The HOE is placed on a bottom surface of the inverted server. The optical sensor is directed at the HOE and configured to detect a fluorescent light emitted from a liquid drop at a first wavelength when illuminated by the light source. The liquid drop lands on the HOE from a cooling liquid. The interference pattern is created by a laser beam operating to form a hologram at a second wavelength substantially close to the first wavelength. ## Claims ### Claim 1 An apparatus comprising: a holographic optical element (HOE) configured to have an interference pattern that functions as mirrors in an inverted server when illuminated by a light source, the HOE being placed on a bottom surface of the inverted server; and an optical sensor directed at the HOE and configured to detect a fluorescent light emitted from a liquid drop at a first wavelength when illuminated by the light source, the liquid drop landing on the HOE from a cooling liquid, wherein the interference pattern is created by a laser beam operating to form a hologram at a second wavelength substantially close to the first wavelength. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the HOE is a holographic film configured to record the interference pattern when placed on the bottom surface and exposed to the laser beam. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the mirrors are virtual mirrors reflecting the objects in the inverted server. ### Claim 4 (depends on 2) The apparatus of claim 2, wherein the holographic film is placed on a diffuse mirror when recording the interference pattern. ### Claim 5 (depends on 3) The apparatus of claim 3, wherein the diffuse mirror is a sheet of metal or frosted glass. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the objects in the inverted server are cooled by the cooling liquid mixed with a fluorescent dye, the cooling liquid flowing in a hose placed through the objects. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the objects in the inverted server are populated on a platform facing downward. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the bottom surface on which the HOE is disposed faces upward to the objects. ### Claim 9 (depends on 1) The apparatus of claim 1 wherein the optical sensor is positioned at or near a focal point of the virtual mirrors. ### Claim 10 (depends on 6) The apparatus of claim 6 wherein the liquid drop lands on the HOE from the cooling liquid as result of a leak. ### Claim 11 A method comprising: placing a holographic optical element (HOE) on a bottom surface of an inverted server, the HOE having an interference pattern that functions as mirrors in the inverted server when illuminated by a light source; and directing an optical sensor at the HOE to detect a fluorescent light emitted from a liquid drop at a first wavelength when illuminated by the light source, the liquid drop landing on the HOE from a cooling liquid, wherein the interference pattern is created by a laser beam operating to form a hologram at a second wavelength substantially close to the first wavelength. ### Claim 12 (depends on 11) The method of claim 11, wherein the HOE is a holographic film configured to record the interference pattern when placed on the bottom surface and exposed to the laser beam. ### Claim 13 (depends on 12) The method of claim 12, wherein the mirrors are virtual mirrors reflecting the objects in the inverted server. ### Claim 14 (depends on 12) The method of claim 12, wherein the holographic film is placed on a diffuse mirror when placed on the bottom surface and exposed to the laser beam. ### Claim 15 (depends on 13) The method of claim 13, wherein the diffuse mirror is a sheet of metal or frosted glass. ### Claim 16 (depends on 11) The method of claim 11, wherein the objects in the inverted server are cooled by the cooling liquid mixed with a fluorescent dye, the cooling liquid flowing in a hose placed through the objects. ### Claim 17 (depends on 11) The method of claim 11, wherein the objects in the inverted server are populated on a platform facing downward. ### Claim 18 (depends on 11) The method of claim 11, wherein the bottom surface on which the HOE is disposed faces upward to the objects. ### Claim 19 (depends on 11) The method of claim 11 wherein the optical sensor is positioned at or near a focal point of the virtual mirrors. ### Claim 20 An information handling system, comprising: a hose that transports cooling liquid mixed with a fluorescent dye in an inverted server; and a leak detector comprising: a holographic optical element (HOE) configured to have an interference pattern that functions as mirrors in the inverted server when illuminated by a light source, the HOE being placed on a bottom surface of the inverted server; and an optical sensor directed at the HOE and configured to detect a fluorescent light emitted from a liquid drop at a first wavelength when illuminated by the light source, the liquid drop landing on the HOE from the cooling liquid, wherein the interference pattern is created by a laser beam operating to form a hologram at a second wavelength substantially close to the first wavelength.