Raman spectrum acquisition system with low background noise

A Raman spectrum and acquisition system technology, applied in Raman scattering, material excitation analysis, etc., can solve the problems of Raman spectrum information flooding and interference, and achieve the effects of reducing interference, increasing luminous flux, and improving signal-to-noise ratio

Inactive Publication Date: 2015-09-09

TIANJIN UNIV

6 Cites 1 Cited by

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Problems solved by technology

However, the intensity of Raman scattered light is only 10 of the excitation light intensity -6 Therefore, when the traditional Raman spectrum acquisition system collects forward or backwar...

Abstract

The invention discloses a Raman spectrum acquisition system with low background noise. By collecting side Raman scattering beams, the Raman spectrum acquisition system acquires a Raman spectrum with low background noise. Through non-coaxial design of excitation light path and Raman scattering light collecting light path, the invention overcomes the problem that the traditional Raman spectrum acquisition system is likely to be interfered by excitation beam dominated strong background noise while collecting forward or backward or Raman scattering beams. At the same time, by means of vertically downward incidence of excitation beams from the position over a sample, a linear excited region can be configured, and the linear excited region matches with a slit in height. The Raman spectrum acquisition system provided by the invention makes full use of the effective range of an array detector's detection surface, increases the luminous flux of Raman scattering beams incident to the array detector, and enhances the signal to noise ratio.

Application Domain

Raman scattering

Technology Topic

Optical pathPhysics +7

Image

Examples

Experimental program(2)

Example Embodiment

[0029] Example 1

[0030] A Raman spectrum acquisition system with low background noise, see figure 1 , Including: continuous laser 1, first filter 2, first convergent lens 3, plane mirror 4, sample cell 5, second convergent lens 6, third convergent lens 7, second filter 8, slit 9. Spectroscopic device 10 and array type detector 11.

[0031] The continuous laser 1 generates a high-power, narrow linewidth excitation beam, and the first filter 2 is a band-pass filter for filtering the stray light of the continuous laser 1 itself. The first condensing lens 3 converges the excitation light beam, and deflects the excitation light beam through the plane mirror 4, so that the excitation light beam enters the sample vertically downward from above the sample cell 5 (preferably directly above), and the excitation beam is excited at the sample cell 5. Mann scattered light beam.

[0032] The linear excited area at the sample cell 5 is imaged at the slit 9 through the second condensing lens 6 and the third condensing lens 7. The height of the linear excited area matches the height of the slit 9, and the sample cell 5 and the slit Slit 9 presents a conjugate relationship of object image figure 1 Use * to indicate). The sample cell 5 is located at the object focal plane of the second converging lens 6, and the slit 9 is located at the image focal plane of the third converging lens 7. The second filter 8 filters out the excitation beam and the Rayleigh scattered beam contained in the side Raman scattered beam.

[0033] The slit 9 limits the width of the lateral Raman scattered light beam that can pass through and affects the spectral resolution. A narrower width corresponds to a higher resolution. The light splitting device 10 splits the side Raman scattered light beams, so that light beams of different frequencies are incident on different positions of the array detector 11. The array detector 11 can use a charge-coupled element (CCD detector) to convert the lateral Raman scattered light beam into an electrical signal, and collect the Raman spectrum.

Example Embodiment

[0034] Example 2

[0035] A Raman spectrum acquisition system with low background noise, see figure 1 with figure 2 , Including: continuous laser 1, first filter 2, first convergent lens 3, plane mirror 4, sample cell 5, second convergent lens 6, third convergent lens 7, second filter 8, slit 9. Spectroscopic device 10 and array type detector 11.

[0036] The continuous laser 1 generates an excitation beam with a center wavelength of 532 nm, a power of not less than 50 mW, and a line width of not more than 0.6 nm. The first filter 2 is a band-pass filter, which is used to filter the stray light of the continuous laser 1 itself. The first condensing lens 3 converges the excitation light beam, and deflects the excitation light beam through the plane mirror 4, so that the excitation light beam enters the sample vertically downward from above the sample cell 5 (preferably directly above), and the excitation beam is excited at the sample cell 5. Mann scattered light beam. The subsequent optical path mainly collects the lateral Raman scattered light beam, forming a non-coaxial design of the excitation light optical path and the Raman scattered light collection optical path. The optical axis L and the optical axis H are not in the same horizontal plane, have different vertical heights, and the optical axis H is higher than the optical axis L.

[0037] Among them, the focal point of the first converging lens 3 is located in the middle of the sample cell 5, and the first converging lens 3 has a longer focal length and a smaller convergence angle at the focal point. (The specific length is determined according to the needs of practical applications. It is assumed that the embodiment of the present invention does not limit this) It can be achieved that the excitation beam has sufficient energy to excite the Raman scattered beam within a certain range on both sides of the focus. At this time, the lateral Raman scattered beam of the sample is not only excited by the excitation beam at the focal point of the first condensing lens 3, but is excited by the excitation beam in a small range on both sides of the focal point. It can be considered as the lateral pull to be collected The Mann scattered light beam originates from a linearly excited area along the vertical direction.

[0038] The linear excited area at the sample cell 5 is imaged at the slit 9 through the second condensing lens 6 and the third condensing lens 7. The height of the linear excited area matches the height of the slit 9, (when the height matches , The collected beams are the most, and the signal-to-noise ratio is the highest.) The sample cell 5 and the slit 9 are in a conjugate relationship of object image ( figure 1 Use * to indicate). The plane A where the sample cell 5 is located and the plane B where the slit 9 is located are both vertical planes, the cuts are parallel to each other and perpendicular to the optical axis L; the sample cell 5 is located at the object focal plane of the second converging lens 6, the slit 9 is located at the image-side focal plane of the third condensing lens 7. The second filter 8 filters out the excitation beam and the Rayleigh scattered beam contained in the side Raman scattered beam.

[0039] Among them, in order to collect as many side Raman scattered light beams as possible and improve the signal-to-noise ratio, the focal length of the second converging lens 6 is small, and the distance between the second converging lens 6 and the third converging lens 7 is as small as possible. The focal length of the condenser lens 7 is not greater than the focal length of the second condenser lens 6.

[0040] The slit 9 limits the width of the lateral Raman scattered light beam that can pass through and affects the spectral resolution. A narrower width corresponds to a higher resolution. The light splitting device 10 splits the side Raman scattered light beams, so that light beams of different frequencies are incident on different positions of the array detector 11. The array detector 11 can use a charge-coupled element (CCD detector) to convert the lateral Raman scattered light beam into an electrical signal, and collect the Raman spectrum.

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Classification and recommendation of technical efficacy words

Reduce background noise
reduce distractions

Systems and methods for the multispectral imaging and characterization of skin tissue

InactiveUS6081612Areduce background noise

Owner:THE TRUSTEES OF COLUMBIA UNIV IN THE CITY OF NEW YORK +1

Means for detection and purification of CD8+ T lymphocyte populations specific to peptides presented in the context of HLA

InactiveUS8309312B2reduce background noise

Owner:INST NAT DE LA SANTE & DE LA RECHERCHE MEDICALE (INSERM)

Raman spectrum acquisition system with low background noise

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Image

Examples

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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