A time-gated Fourier Raman fluorescence lifetime device

Abstract

The present invention provides a time-gated Fourier Raman fluorescence lifetime device, comprising: a laser module, a Raman imaging module, an interference module, a calibration module, and a detection module; the device greatly improves the time resolution and Raman spectrum resolution of the device, not only realizing Fourier time-gated Raman, achieving a time resolution of 300 picoseconds, and obtaining a 4-dimensional Raman spectrum, but also realizing the two functions of testing Raman spectrum and fluorescence lifetime imaging, combining the two instrument functions into one, reducing the research costs of scientific researchers, and having a broad scientific research market.

Description

Technical Field

[0001] The invention relates to the field of optical technology, in particular to a time-gated Fourier Raman fluorescence lifetime device. Background Art

[0002] Time-gated Raman principle: When a laser pulse acts on a sample, it generates Raman and fluorescence signals. Generally speaking, the Raman signal appears 300 picoseconds earlier than the fluorescence signal, so we need to set a time gate; Figure 5 As shown, only specific signals within the frame are detected each time, so that a relatively pure Raman spectrum can be obtained and most of the fluorescence signals can be discarded.

[0003] In the existing technology, time-gated Raman devices are all built on the grating principle. However, grating Raman instruments cannot achieve high time resolution and high Raman spectral resolution Raman spectra for samples, and cannot simultaneously detect the fluorescence lifetime of the samples. Summary of the Invention

[0004] In order to overcome the shortcomings of the existing technology, the present invention provides a time-gated Fourier Raman fluorescence lifetime device, which can simultaneously realize time-gated Raman detection and fluorescence lifetime detection. The device has an ingenious structural design, which greatly improves the time resolution and Raman spectrum resolution of the device. The device not only realizes Fourier time-gated Raman, achieves a time resolution of 300 picoseconds, and obtains a 4-dimensional Raman spectrum, but also realizes the two functions of testing Raman spectrum and fluorescence lifetime imaging, combining the functions of the two instruments into one, reducing the research costs of scientific researchers, and has a broad scientific research market.

[0005] The technical solution adopted by the present invention to solve the above technical problems is:

[0006] A time-gated Fourier Raman fluorescence lifetime device comprises: a laser module, a Raman imaging module, an interference module, a calibration module and a detection module;

[0007] The laser module includes: a picosecond pulse laser and a first collimator mirror, wherein the first collimator mirror is arranged on the left side of the picosecond pulse laser;

[0008] As an example, the specification of the picosecond pulse laser is: 532nm.

[0009] The Raman imaging module includes: an imaging camera, an objective lens, a first focusing lens, a first 50% beam splitter, a second 50% beam splitter, a first reflector, a second reflector, a first filter, a second filter, a third filter and a first LED;

[0010] Wherein: the objective lens is arranged directly above the sample; the first 50% beam splitter is arranged above the objective lens; the first reflector is arranged on the right side of the first 50% beam splitter; the second 50% beam splitter is arranged on the left side of the first 50% beam splitter; the first LED is arranged above the second 50% beam splitter; the first focusing lens is arranged on the left side of the second 50% beam splitter; the imaging camera is arranged on the left side of the first focusing lens; a first filter and a second reflector are arranged in sequence above the first 50% beam splitter; a second filter and a third filter are arranged in sequence on the right side of the second reflector;

[0011] As an example, the first filter, the second filter, and the third filter are all 532nm long-pass filters. Filters of this specification can effectively filter out stray light.

[0012] The interference module includes: a fourth filter, a fifth filter, a third 50% beam splitter, a third reflecting mirror, a fourth reflecting mirror, a translation stage, a first corner mirror, a second corner mirror and a single-mode laser;

[0013] Wherein: a fourth filter and a fifth filter are sequentially arranged on the left side of the third 50% beam splitter; a fourth reflector is arranged on the right side of the third 50% beam splitter; the second corner mirror is arranged at the lower left of the fourth reflector; the first corner mirror is arranged at the upper right of the third reflector; the first corner mirror and the second corner mirror are symmetrically arranged on both sides of the translation stage; one end of the fourth filter is connected to one end of the third filter through an optical fiber;

[0014] The calibration module includes: a 5% beam splitter, a 10% beam splitter, a second collimator and a second LED;

[0015] Wherein: the 5% beam splitter is arranged above the third 50% beam splitter; the 10% beam splitter is arranged above the single-mode laser; a second collimator and a second LED are arranged on the right side of the 10% beam splitter in sequence; one end of the second LED is electrically connected to one end of the picosecond pulse laser;

[0016] As an example, the electrical signal between one end of the second LED and the picosecond pulse laser is a synchronization signal;

[0017] The detection module includes: a single photon avalanche diode, a second focusing lens and a single photon counter;

[0018] Wherein: the second focusing lens is arranged above the 5% beam splitter; the single photon avalanche diode is arranged above the second focusing lens; one end of the single photon counter is electrically connected to one end of the single photon avalanche diode, and the other end of the single photon counter is electrically connected to the other end of the second LED;

[0019] Furthermore, the laser light emitted by the picosecond pulse laser passes through a first collimator, a first reflector, a first filter, and a first 50% beam splitter, and then acts on the sample through an objective lens, thereby stimulating Raman light of the sample, i.e., a Raman signal. The Raman signal returns to the optical path, passes through a first filter and a second filter to filter out stray light, and then is connected to an optical fiber. After the Raman signal enters the interferometer module through the optical fiber, the Raman signal is separated and expanded into a spectral signal. The spectral signal is optically calibrated by a calibration module, and finally, the spectral signal is collected and processed by a single-photon avalanche diode and a single-photon counter, and then transmitted to a computer, thereby ultimately achieving fluorescence lifetime imaging and Raman signal acquisition.

[0020] The collected Raman signal can achieve a time resolution of 300ps and 0.1cm -1 Spectral resolution of wavenumber, 0-7000cm -1 The spectral range of wavenumbers.

[0021] Beneficial effects of the present invention:

[0022] The time-gated Raman technology of the present invention is different from conventional Raman systems, which cannot separate Raman signals from fluorescence signals.

[0023] The present invention can not only realize the separation of Raman signals and fluorescence signals, but also realize fluorescence lifetime measurement.

[0024] Different from the world's only commercial time-gated Raman spectrometer (grating type), the present invention uses a Fourier method to process signals, which is different from its grating type spectrum processing method. It is superior to the existing technology in terms of time resolution, spectral accuracy and spectral range.

[0025] The present invention truly achieves time-gated Raman, the device structure is scientifically and rigorously designed, and the operation is safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of a time-gated Fourier Raman fluorescence lifetime device of the present invention.

[0027] Figure 2 This is a reference diagram of the sample measured results of a time-gated Fourier Raman fluorescence lifetime device of the present invention (rhodamine 6G & polyvinyl alcohol & silicon wafer time-gated Raman resolution effect diagram).

[0028] Figure 3This is a diagram showing the time delay effect of Rhodamine 6G, polyvinyl alcohol, and silicon wafer time-gated control of a time-gated Fourier Raman fluorescence lifetime device according to the present invention.

[0029] Figure 4 This is a schematic diagram of fluorescence interface fluorescence lifetime imaging of a time-gated Fourier Raman fluorescence lifetime device of the present invention.

[0030] Figure 5 This is a background technology reference diagram of a time-gated Fourier Raman fluorescence lifetime device of the present invention. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0032] Reference Figures 1 to 5 As shown: A time-gated Fourier Raman fluorescence lifetime device, comprising: a laser module 101, a Raman imaging module 102, an interference module 103, a calibration module 104 and a detection module 105;

[0033] The laser module 101 includes: a picosecond pulse laser 106 and a first collimator 107, wherein the first collimator 107 is arranged on the left side of the picosecond pulse laser 106;

[0034] As an example, the specification of the picosecond pulse laser 106 is: 532nm.

[0035] The Raman imaging module 102 includes: an imaging camera 108, an objective lens 109, a first focusing lens 110, a first 50% beam splitter 111, a second 50% beam splitter 112, a first reflector 113, a second reflector 114, a first filter 115, a second filter 116, a third filter 117 and a first LED 118;

[0036] Wherein: the objective lens 109 is arranged directly above the sample; the first 50% beam splitter 111 is arranged above the objective lens 109; the first reflector 113 is arranged on the right side of the first 50% beam splitter 111; the second 50% beam splitter 112 is arranged on the left side of the first 50% beam splitter 111; the first LED 118 is arranged above the second 50% beam splitter 112; the first focusing lens 110 is arranged on the left side of the second 50% beam splitter 112; the imaging camera 108 is arranged on the left side of the first focusing lens 110; a first filter 115 and a second reflector 114 are arranged in sequence above the first 50% beam splitter 111; a second filter 116 and a third filter 117 are arranged in sequence on the right side of the second reflector 114;

[0037] As an example, the first filter 115 , the second filter 116 , and the third filter 117 are all 532 nm long-pass filters, and filters of this specification can effectively filter out stray light.

[0038] The interference module 103 includes: a fourth filter 202, a fifth filter 201, a third 50% beam splitter 203, a third reflector 204, a fourth reflector 205, a translation stage 206, a first corner mirror 207, a second corner mirror 208 and a single-mode laser 209;

[0039] Wherein: the fourth filter 202 and the fifth filter 201 are sequentially arranged on the left side of the third 50% beam splitter 203; the fourth reflector 205 is arranged on the right side of the third 50% beam splitter 203; the second corner mirror 208 is arranged at the lower left of the fourth reflector 205; the first corner mirror 207 is arranged at the upper right of the third reflector 204; the first corner mirror 207 and the second corner mirror 208 are symmetrically arranged on both sides of the translation stage 206; one end of the fourth filter 202 is connected to one end of the third filter 117 via an optical fiber;

[0040] As an example, the specification of the single-mode laser 209 is also 532 nm.

[0041] The calibration module 104 includes: a 5% beam splitter 301, a 10% beam splitter 302, a second collimator 303 and a second LED 304;

[0042] The 5% beam splitter 301 is disposed above the third 50% beam splitter 203; the 10% beam splitter 302 is disposed above the single-mode laser 209; a second collimator 303 and a second LED 304 are sequentially disposed on the right side of the 10% beam splitter 302; one end of the second LED 304 is electrically connected to one end of the picosecond pulse laser 106;

[0043] As an example, the electrical signal between one end of the second LED 304 and the picosecond pulse laser 106 is a synchronization signal;

[0044] The detection module 105 includes: a single photon avalanche diode 401, a second focusing lens 402 and a single photon counter 403;

[0045] Wherein: the second focusing lens 402 is arranged above the 5% beam splitter 301; the single photon avalanche diode 401 is arranged above the second focusing lens 402; one end of the single photon counter 403 is electrically connected to one end of the single photon avalanche diode 401, and the other end of the single photon counter 403 is electrically connected to the other end of the second LED 304;

[0046] Furthermore, the laser light emitted by the picosecond pulse laser 106 passes through the first collimator 107, the first reflector 113, the first filter 115, and the first 50% beam splitter 111, and then acts on the sample through the objective lens 109, thereby stimulating the Raman light of the sample, i.e., the Raman signal. The Raman signal returns to the optical path and passes through the first filter 115, the second filter 116, and the third filter 117 to filter out stray light before being connected to the optical fiber. The Raman signal enters the interference module 103 through the optical fiber, where it is separated and expanded into a spectral signal. The spectral signal is optically calibrated by the calibration module 104, and finally, the spectral signal is collected and processed by the single-photon avalanche diode 401 and the single-photon counter 403 before being transmitted to the computer, thereby ultimately achieving fluorescence lifetime imaging and Raman signal acquisition.

[0047] The collected Raman signal can achieve a time resolution of 300ps and 0.1cm -1 Spectral resolution of wavenumber, 0-7000cm -1 The spectral range of wavenumbers.

[0048] In order to better illustrate the principle of the present invention, specific embodiments are given as follows:

[0049] Example 1:

[0050] The device of the present invention was used to test the fluorescent material Rhodamine 6G, polyvinyl alcohol, and silicon wafer. The test sample had both Raman signals and strong fluorescence signals. The sample was used to verify the spectral separation performance of the present invention.

[0051] The test results are as follows Figure 2 As shown, Figure 2 (a) is a physical picture of the test sample; Figure 2 In (b), it can be seen that the sample has a long fluorescence lifetime;

[0052] And from Figure 2 Comparing (c) and (d), in the case of shorter gating time, such as 0-1000 picoseconds, the Raman spectrum has both the Raman peak of silicon and the fluorescence spectrum;

[0053] However, under higher time gating conditions, such as 1000-10000 picoseconds, the Raman spectrum only has the fluorescence spectrum but no Raman peak of silicon, which shows that the instrument has achieved the spectral and temporal distinction between fluorescence and Raman, achieving the intended purpose.

[0054] Further, from Figure 3It can be seen that the Raman spectrum results change with time delay. There is an obvious Raman peak of silicon in the early stage of time delay, but as the time delay increases, only the fluorescence Raman spectrum exists later, further confirming that the ability of the present invention to distinguish between Raman and fluorescence spectra is very significant.

[0055] The present invention can not only test Raman spectrum, but also realize the test of fluorescence lifetime. The present invention is used to test the interface between two fluorescent materials. The test results are as follows: Figure 4 As shown:

[0056] from Figure 4 (a) is the real image formed by the field of view of the optical imaging camera 108.

[0057] Figure 4 (b), (c), and (d) are fluorescence lifetime imaging diagrams at the junction. It can be seen that the two fluorescent substances have different fluorescence lifetimes and the distinction is very high. In addition, the imaging accuracy of the device of the present invention is very high, meeting the actual experimental requirements.

[0058] The time-gated Raman technology of the present invention is different from conventional Raman systems, which cannot separate Raman signals from fluorescence signals. The present invention can not only separate Raman signals from fluorescence signals, but also measure fluorescence lifetime. It is different from the world's only commercial time-gated Raman spectrometer (grating type) in that it uses a Fourier method to process signals, rather than a grating type spectral processing method. It is superior to the existing technology in terms of time resolution, spectral accuracy, and spectral range. The present invention truly achieves time-gated Raman, the device structure is scientifically and rigorously designed, and the operation is safe and reliable.

[0059] The above are only preferred embodiments of the present invention. It should be understood that the description of the above embodiments is only used to help understand the method and core ideas of the present invention, and is not used to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, etc. made within the ideas and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A time-gated Fourier Raman fluorescence lifetime device, characterized in that: include: Laser module, Raman imaging module, interference module, calibration module and detection module; The laser module includes: a picosecond pulse laser and a first collimating mirror; The Raman imaging module includes: an objective lens, which is arranged directly above the sample; a first 50% beam splitter is arranged above the objective lens; a first reflector is arranged on the right side of the first 50% beam splitter; a second 50% beam splitter is arranged on the left side of the first 50% beam splitter; a first LED is arranged above the second 50% beam splitter; a first focusing lens is arranged on the left side of the second 50% beam splitter; an imaging camera is arranged on the left side of the first focusing lens; a first filter and a second reflector are arranged in sequence above the first 50% beam splitter; and a second filter and a third filter are arranged in sequence on the right side of the second reflector. The interference module includes: a third 50% beam splitter, with a fourth filter and a fifth filter arranged in sequence on the left side of the third 50% beam splitter; a fourth reflector arranged on the right side of the third 50% beam splitter; a second corner mirror arranged at the lower left of the fourth reflector; a first corner mirror arranged at the upper right of the third reflector; the first and second corner mirrors arranged symmetrically on both sides of the translation stage; one end of the fourth filter is connected to one end of the third filter via an optical fiber; The calibration module includes: a 5% beam splitter, which is arranged above the third 50% beam splitter; a 10% beam splitter, which is arranged above the single-mode laser; a second collimator and a second LED are arranged on the right side of the 10% beam splitter; one end of the second LED is electrically connected to one end of the picosecond pulse laser; the electrical signal between one end of the second LED and the picosecond pulse laser is a synchronization signal; The detection module includes: a second focusing lens, which is arranged above the 5% beam splitter; a single-photon avalanche diode is arranged above the second focusing lens; one end of the single-photon counter is electrically connected to one end of the single-photon avalanche diode, and the other end of the single-photon counter is electrically connected to the other end of the second LED; The laser emitted by the picosecond pulse laser passes through the first collimator, the first reflector, the first filter, and the first 50% beam splitter, and then acts on the sample through the objective lens, exciting the sample's Raman light, namely the Raman signal; the Raman signal returns to the optical path and passes through the first filter and the second filter to filter out stray light before being connected to the optical fiber. After the Raman signal enters the interferometer module through the optical fiber, the Raman signal is separated and expanded into a spectral signal; the spectral signal is optically calibrated by the calibration module, and finally passes through the single-photon avalanche diode and the single-photon counter to collect and process the spectral signal and transmit it to the computer to achieve fluorescence lifetime imaging and Raman signal acquisition.

2. The time-gated Fourier Raman fluorescence lifetime device according to claim 1, characterized in that: The first collimating mirror is arranged on the left side of the picosecond pulse laser.

3. The time-gated Fourier Raman fluorescence lifetime device according to claim 1, characterized in that: The specification of the picosecond pulse laser is: 532nm.

4. The time-gated Fourier Raman fluorescence lifetime device according to claim 1, characterized in that: The first filter, the second filter, and the third filter are all 532nm long-pass filters. Filters of this specification can effectively filter out stray light.

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