3D laser ablation tomography and spectrographic analysis

• US 9,835,532 B2
• Filed: 10/30/2013
• Issued: 12/05/2017
• Est. Priority Date: 10/30/2012
• Status: Active Grant

• Current Assignee: Penn State Research Foundation
• Original Assignee: Penn State Research Foundation
• Inventors: Hall, Benjamin, Lynch, Jonathan, Reutzel, Edward W., Lynch, Galen, Reinhardt, Brian T.
• Primary Examiner(s): Ayub, Hina F
• Application Number:
  US14/646,250
• Publication Number:
  US 20150323431A1
• Time in Patent Office: 1,497 Days
• Field of Search: 356 72
• CPC Class Codes: G01J 2003/106 the two sources being alternating or selectable, e.g. in two ranges or line:continuum
• CPC Class Codes: G01J 3/00 Spectrometry; Spectrophotometry; Monochromators; Measuring colours
• CPC Class Codes: G01J 3/2823 Imaging spectrometer
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01J 3/443 Emission spectrometry
• CPC Class Codes: G01N 1/06 providing a thin slice, e.g. microtome
• CPC Class Codes: G01N 1/44 Sample treatment involving radiation, e.g. heat
• CPC Class Codes: G01N 2001/045 Laser ablation; Microwave vaporisation
• CPC Class Codes: G01N 2001/2886 Laser cutting, e.g. tissue catapult
• CPC Class Codes: G01N 2201/06113 Coherent sources; lasers

Abstract

A laser ablation tomography system includes a specimen stage for supporting a specimen. A specimen axis is defined such that a specimen disposed generally on the axis may be imaged. A laser system is operable to produce a laser sheet in a plane intersecting the specimen axis and generally perpendicular thereto. An imaging system is operable to image the area where the laser sheet intersects the specimen axis.

Claims

1. A laser ablation tomography and spectroscopic analysis system, comprising:

a specimen stage for supporting a specimen to be imaged, a specimen axis being defined from a fore end of the specimen to an aft end of the specimen;

a laser system operable to produce a laser sheet in an imaging plane intersecting the specimen axis substantially perpendicular thereto, the laser sheet operable to ablate a cross-sectional slice of the specimen at the imaging plane thereby exposing a cross-sectional surface of the specimen at the imaging plane;

an imaging system operable to image the cross-sectional surface of the specimen being ablated during, before or after the laser sheet ablates the cross-sectional slice of the specimen; and

a spectrometer operable to capture light from the cross-sectional surface of the specimen.

2. A laser ablation tomography and spectroscopic analysis system in accordance with claim 1, further comprising:

a movement system operable to cause relative movement between the specimen stage and the laser sheet along the specimen axis.

3. A laser ablation tomography and spectroscopic analysis system in accordance with claim 2, further comprising:

a control system operable to control the imaging system and the movement system.

4. A laser ablation tomography and spectroscopic analysis system in accordance with claim 1, wherein the imaging system comprises a camera with a Charged Coupled Device (CCD).

5. A laser ablation tomography and spectroscopic analysis system in accordance with claim 1, wherein:

the laser system is operable in a first mode of operation to produce the laser sheet and further operable in a second mode of operation to produce a laser beam for irradiating a small area of the specimen,

the spectrometer arranged to capture light from the irradiated area when the laser system operates in the second mode of operation.

6. A laser ablation tomography and spectroscopic analysis system in accordance with claim 5, wherein the laser system further comprises beam shaping optics disposed such that the beam from the laser passes therethrough.

7. A laser ablation tomography and spectroscopic analysis system in accordance with claim 5, wherein:

the laser beam from the laser system in the second mode of operation is generally perpendicular to the plane defined by the laser sheet.

8. A laser ablation tomography and spectroscopic analysis system in accordance with claim 5, wherein:

the laser system comprises a laser operable to produce a laser beam and a beam director operable in the first mode of operation to rapidly scan the laser beam so as to create the laser sheet and in the second mode of operation to position the laser beam for irradiating the small area.

9. A laser ablation tomography and spectroscopic analysis system in accordance with claim 8, wherein:

the laser system further comprises at least one beam splitter disposed between the specimen stage and the imaging system, the laser beam in the second mode of operation hitting the beam splitter.

10. A laser ablation tomography and spectroscopic analysis system in accordance with claim 5, wherein:

the imaging system is further operable to capture a location of the irradiation when the laser system is in the second mode of operation.

11. A laser ablation tomography and spectroscopic analysis system in accordance with claim 5, wherein:

the laser system comprises a first laser operable to produce a first laser beam and a second laser operable to produce a second laser beam,

the laser system further comprising a beam director operable in the first mode of operation to rapidly scan the first laser beam so as to create the laser sheet and in the second mode of operation to position the second laser beam for irradiating the small area.

12. A laser ablation tomography and spectroscopic analysis system in accordance with claim 11, further comprising:

a beam splitter positioned where the laser beams from the lasers intersect so that the laser beams share a beam path after the beam splitter.

13. A laser ablation tomography and spectroscopic analysis system in accordance with claim 11, wherein:

the first laser is a femtosecond or picosecond laser.

14. A laser ablation tomography and spectroscopic analysis system in accordance with claim 11, wherein:

the second laser is selected from the group consisting of a short pulsed tunable laser and a continuous laser with narrow bandwidth.

15. A method for laser ablation tomography and spectroscopic analysis, comprising the steps of:

providing the laser ablation tomography and spectroscopic analysis system of claim 1;

positioning a specimen on the specimen stage such that a portion of the specimen may be ablated;

ablating the specimen with the laser sheet;

imaging the specimen where it was ablated;

irradiating a portion of the specimen with the laser beam;

analyzing the irradiated portion of the specimen with the spectrometer; and

repeating the positioning, ablating, irradiating, imaging and/or analyzing steps.

16. A method in accordance with claim 15, wherein:

the imaging step is performed during the ablating with the laser sheet step.

17. A laser ablation tomography and spectroscopic analysis system in accordance with claim 1, wherein the laser system is operable to produce a laser beam to irradiate a portion of the specimen by illuminating or ablating the portion of the specimen.