# US 10,502,624 B2 · Compact apparatus for laser induced breakdown spectroscopy and method therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,624 B2 - Document ID: US10502624B2 - Status: Granted - Kind: B2 - Application number: 15/524,585 - Filed: 2015-11-06 - Published: 2018-10-04 - Granted: 2019-12-10 - Earliest claimed: 2014-11-07 - Assignees: National Research Council of Canada - Applicants: National Research Council Canada - Inventors: Paul Bouchard; Mohamad Sabsabi; Francois Doucet; Lütfü Celebi Özcan - Web page: https://patentgrep.com/patent/US10502624B2 ## CPC - G01J 3/443: Emission spectrometry - G01J 3/0208: {using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction} - G01J 3/0243: {having a through-hole enabling the optical element to fulfil an additional optical function, e.g. a mirror or grating having a throughhole for a light collecting or light injecting optical fiber} - G01N 21/718: {Laser microanalysis, i.e. with formation of sample plasma} - G01N 2201/0221: Portable; cableless; compact; hand-held - G01N 2201/0636: Reflectors - G01N 2201/0638: Refractive parts - G02F 1/294: {Variable focal length devices} - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - 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) - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## Abstract The present invention provides a method and compact apparatus for laser induced breakdown atomic emission spectroscopy from a targeted sample having a laser generating a laser beam, the laser beam directed to the sample, optical means for manipulating the laser beam in order maximize laser fluency at the target surface of the sample, the laser beam generating ablation and plasma emission from the sample at the target surface, an emission spectrometer having a detector for detecting a plasma plume from the plasma emission. ## Claims ### Claim 1 A method of laser induced breakdown spectroscopy comprising: directing a laser beam to a target plane on a sample, the target plane located on a proximal surface of the sample; manipulating the laser beam to substantially maximize threshold fluency at the target plane; generating ablation and plasma emission from the sample at the target plane; wherein manipulating the laser beam to substantially maximize threshold fluency at the target plain is performed with an optical instrument; wherein the optical instrument is an electronically tunable lens and further comprises a photodiode generating a photodiode output and wherein manipulating the laser beam to substantially maximize threshold fluency at the target plane is achieved by adjusting the electronically tunable lens such that a normalized intensity of the photodiode output is coincident with an observed normalized intensity of ionic lines detected from the sample during ablation and plasma emission of the sample. ### Claim 2 (depends on 1) The method of claim 1 wherein manipulating the laser beam to substantially maximize threshold fluency at the target plane further comprises focusing the laser beam on the target plane to create a resultant laser beam such that a focusing plane of the resultant laser beam is substantially coincident with the target plane. ### Claim 3 (depends on 1) The method of claim 1 wherein manipulating the laser beam to substantially maximize threshold fluency at the target plane further comprises reducing a diameter of the laser beam. ### Claim 4 (depends on 1) The method of claim 1 wherein the sample degrades at the target plane due to ablation of the sample thereby creating a second target plane on the sample distally removed from the target plane, the method further comprising: manipulating the laser beam to substantially maximize threshold fluency at the second target plane resulting in a second resultant laser beam such that the focusing plane of the second resultant laser beam is substantially coincident with the second target plane; and generating ablation and plasma emission from the sample at the second target plane. ### Claim 5 (depends on 4) The method of claim 4 wherein manipulating the laser beam to substantially maximize threshold fluency at the second target plane further comprises focusing the laser beam on the second target plane. ### Claim 6 (depends on 4) The method of claim 4 wherein manipulating the laser beam to substantially maximize threshold fluency at the second target plane further comprises moving the laser beam to a radially disposed second position, the second position selected from a random beam sweep pattern. ### Claim 7 (depends on 4) The method of claim 4 wherein manipulating the laser beam to substantially maximize threshold fluency at the second target plane further comprises reducing a diameter of the laser beam. ### Claim 8 (depends on 4) The method of claim 4 wherein manipulating the laser beam to maximize threshold fluency at the second target plane is performed with an optical instrument selected from the group consisting of: a single-axis electronically tunable lens, a focusing lens, a beam reducing lens and combinations thereof. ### Claim 9 (depends on 1) The method of claim 1 further comprising the steps of: detecting a plasma plume emanating from the sample, and spectroscopically analyzing the plasma plume to determine chemical composition of the sample. ### Claim 10 (depends on 9) The method of claim 9 wherein the plasma plume is detected using achromatic reflective optics. ### Claim 11 (depends on 10) The method of claim 10 wherein the achromatic reflective optics are a plurality of concavely parabolic mirrors, each of the plurality of concavely parabolic mirrors having a reflective surface facing the sample, each of the plurality of concavely parabolic mirrors radially removed from a central axis that is coincident with the laser beam, each of the plurality of concavely parabolic mirrors visually communicating with an emission spectrometer. ### Claim 12 (depends on 11) The method of claim 11 further comprising an auxiliary parabolic mirror, the auxiliary concavely parabolic mirror radially removed from the central axis, the auxiliary parabolic mirror visually communicating with each of the plurality of mirrors and the emission spectrometer. ### Claim 13 A method of laser induced breakdown spectroscopy comprising: directing a laser beam to a target plane on a sample, the target plane located on a proximal surface of the sample; manipulating the laser beam to substantially maximize threshold fluency at the target plane; generating ablation and plasma emission from the sample at the target plane; redirecting the laser beam to a first radially removed target plane, the first radially removed target plane radially displaced from the target plane; manipulating the laser beam to substantially maximize threshold fluency at the first radially removed target plane thereby creating a resultant redirected laser beam such that the focusing plane of the resultant redirected laser beam is substantially coincident with the first radially removed target plane; and generating ablation and plasma emission from the sample at the first radially removed target plane target plane. ### Claim 14 (depends on 13) The method of claim 13 wherein manipulating the laser beam to substantially maximize threshold fluency at the first radially removed target plane further comprises focusing the laser beam on the target plane. ### Claim 15 (depends on 13) The method of claim 13 wherein manipulating the laser beam to substantially maximize threshold fluency at the first radially removed target plane further comprises reducing a diameter of the laser beam. ### Claim 16 (depends on 13) The method of claim 13 wherein the first radially removed target plane is selected from a random beam sweep pattern. ### Claim 17 (depends on 13) The method of claim 13 wherein manipulating the laser beam to substantially maximize threshold fluency at the first radially removed target plane is performed with an optical instrument selected from the group consisting of: a Risley prisms pair, a three-axis electronically tunable lens, a radially translating focusing lens and combinations thereof. ### Claim 18 An apparatus for laser induced breakdown spectroscopy of a sample comprising: a laser source generating a laser beam, the laser beam directed to the sample; optical means for manipulating the laser beam to substantially maximize laser fluency at a target surface of the sample, the laser beam generating ablation and plasma emission from the sample at the target surface; an emission spectrometer having a detector for detecting a plasma plume from the plasma emission; and wherein the optical means are selected from the group consisting of a three-axis electronically tunable lens and a single-axis electronically tunable lens and wherein the optical means further comprises a photodiode adapted to generate a photodiode output. ### Claim 19 (depends on 18) The apparatus for laser induced breakdown spectroscopy of claim 18 wherein the optical means is further configured to focus the laser beam on the target surface to create a resultant laser beam such that a focusing plane of the laser beam is substantially coincident with the target surface of the sample. ### Claim 20 (depends on 18) The apparatus for laser induced breakdown spectroscopy of claim 18 wherein the optical means is further configured to reduce a diameter of the laser beam. ### Claim 21 (depends on 18) The apparatus of claim 18 wherein the plasma emission is detected using achromatic reflective optics. ### Claim 22 (depends on 21) The apparatus of claim 21 wherein the achromatic reflective optics are a plurality of concavely parabolic mirrors, each of the plurality of concavely parabolic mirrors having a reflective surface facing the sample, each of the plurality of concavely parabolic mirrors radially removed from a central axis that is coincident with the laser beam, each of the plurality of concavely parabolic mirrors visually communicating with the detector of the emission spectrometer. ### Claim 23 (depends on 22) The apparatus of claim 22 further comprising an auxiliary parabolic mirror, the auxiliary concavely parabolic mirror radially removed from the central axis, the auxiliary concavely parabolic mirror visually communicating with each of the plurality of concavely parabolic mirrors and the detector of the emission spectrometer.