3-Color multiplex cars spectrometer

• US 20100020318A1
• Filed: 12/29/2008
• Published: 01/28/2010
• Est. Priority Date: 07/24/2008
• Status: Active Grant

• Current Assignee: Korea Research Institute of Standards and Science
• Original Assignee: Korea Research Institute of Standards and Science
• Inventors: Moon, Dae Won, Lee, Eun Seong, Lee, Jae Yong
• Granted Patent: US 8,064,053 B2
• Time in Patent Office: Days
• US Class Current: 356/301
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0227 using notch filters
• CPC Class Codes: G01J 3/0237 Adjustable, e.g. focussing
• CPC Class Codes: G01J 3/4412 Scattering spectrometry particle sizing by light scattering G01N15/0205; optical velocimetry of particles G01P5/20, G01P5/26

Abstract

The present invention relates to a 3-color multiplex CARS spectrometer. In the 3-color multiplex CARS spectrometer, Raman resonance is achieved for multiple molecular vibrations of a sample by the combination of a short-wavelength pump beam generated by a broadband laser light source and a long-wavelength Stokes beam generated by a stable laser light source, and another short-wavelength laser beam having a narrow linewidth is then introduced separately to serve as a probe beam that interacts with the laser-driven sample, thereby generating CARS spectral signals whose wavelength components can be resolved. Accordingly, the 3-color multiplex CARS spectrometer solves problem of the conventional 2-color multiplex CARS spectroscopy in which the wavelength decomposition of CARS signals, necessary for high spectral resolution, is not possible with broadband pump light causing the CARS spectrum distortion.

Claims

1. A 3-color multiplex CARS spectrometer, comprising:

a broadband laser light source 10 generating a pump beam for multiply exciting molecular vibrations of media constituting a sample;

a Stokes laser light source 20 generating a Stokes beam for allowing the multiply excited molecular vibration to resonate while interacting with the pump beam;

a probe laser light source 30 generating a probe beam for generating a multiplex CARS spectrum signal from the resonance-excited molecular vibration of the sample;

a beam combiner 40 temporally synchronizing optical pulse outputs of the pump, Stokes and probe beams, and spatially overlapping the pump, Stokes and probe beams on the same axis;

a microscope objective 50 focusing the synchronized and spatially overlapped laser beam onto a point in the sample;

a sample displacement scanner 60 arbitrarily adjusting the position of a focus of the laser beam in the sample focused by the microscope objective 50;

a condensing optical system 70 condensing and collimating a CARS signal generated at the focus of the sample;

a dichroic mirror 80 or notch filter removing the incident laser and noise wavelength components contained in the condensed CARS signal;

a monochromator 90 spatially dispersing wavelength components of the pure CARS signal from which the incident laser and noise wavelength components are removed;

a 1D/2D photodetector array 100 detecting a multiplex CARS spectral signal wavelength-dispersed by the monochromator 90; and

a data analyzer 110 transferring the wavelength-dispersed multiplex CARS spectral signal detected by the 1D/2D photodetector array 100 to a computer and performing data analysis.

2. The 3-color multiplex CARS spectrometer as set forth in claim 1, wherein the probe laser light source 30 uses a laser beam having a shorter wavelength than that of the Stokes beam so that a 3-color multiplex CARS spectral signal generated using the pump, Stokes and probe beams is separated from a distorted 2-color multiplex CARS spectral signal generated using the pump and Stokes beams.

3. The 3-color multiplex CARS spectrometer as set forth in claim 1, wherein the sample displacement scanner 60 includes a manual, motorized or piezoelectric-transducer mechanical translator that allows the position in the sample from which a multiplex CARS signal is detected to be arbitrarily designated by changing the laser focus in the sample focused by the microscope objective 50 in the direction of the XY plane and the optical axis (Z-axis).

4. The 3-color multiplex CARS spectrometer as set forth in claim 1, wherein the monochromator 90 uses a grating or prism as a wavelength dispersion element so as to allow the wavelength components of the CARS signal to be spatially dispersed.

5. The 3-color multiplex CARS spectrometer as set forth in claim 1, wherein the 1D/2D photodetector array 100 includes any one selected from the group consisting of a 1- or 2-dimensional charge coupled device (CCD) having a high sensitivity and a low noise level, a cooled CCD, an intensified CCD and an EMCCD.

6. A 3-color multiplex CARS spectral microscope, wherein the 3-color multiplex CARS spectrometer according to claim 1 is used in a microscopic imaging device.

7. A 3-color multiplex CARS spectral microscope, wherein the 3-color multiplex CARS spectrometer according to claim 2 is used in a microscopic imaging device.

8. A 3-color multiplex CARS spectral microscope, wherein the 3-color multiplex CARS spectrometer according to claim 3 is used in a microscopic imaging device.

9. A 3-color multiplex CARS spectral microscope, wherein the 3-color multiplex CARS spectrometer according to claim 4 is used in a microscopic imaging device.

10. A 3-color multiplex CARS spectral microscope, wherein the 3-color multiplex CARS spectrometer according to claim 5 is used in a microscopic imaging device.