CN117030676A - Low-cost surface-enhanced Raman spectrum detection method, system and storage medium - Google Patents
Low-cost surface-enhanced Raman spectrum detection method, system and storage medium Download PDFInfo
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Abstract
The invention relates to the technical field of data detection, in particular to a low-cost surface-enhanced Raman spectrum detection method, a system and a storage medium. The method comprises the steps that a laser and an object to be detected are respectively arranged at two ends of an optical fiber, an optical fiber SERS probe is prepared on a detection end face, an optical fiber grating structure is prepared on the optical fiber, when the laser is started, the laser emits Raman excitation light and reaches the detection end face along the optical fiber, the optical fiber SERS probe on the detection end face excites the object to be detected, SERS spectrums of the object to be detected are collected, the optical fiber SERS probe returns the SERS spectrums of the object to be detected to the optical fiber grating through the optical fiber, the optical fiber grating reflects the SERS spectrums of the object to be detected meeting a first condition to an optical notch filter, and then reaches an intensity detector after passing through the optical notch filter, the intensity detector obtains intensity data of the optical fiber SERS probe, and therefore concentration data of the object to be detected are calculated. The invention simplifies the optical system and reduces the detection cost.
Description
Technical Field
The invention relates to the technical field of data detection, in particular to a low-cost surface-enhanced Raman spectrum detection method, a system and a storage medium.
Background
Because raman spectra are closely related to the vibrational and rotational energy levels of molecules, raman spectra are commonly used to model substancesAnd (5) detecting and identifying the score. Surface enhanced raman scattering developed in recent years achieves a great enhancement of raman spectrum signals by utilizing localized surface plasmon resonance characteristics of noble metal nanoparticles (enhancement factor can reach 10) 6 -10 12 Magnitude), greatly motivated the development of raman spectroscopy. At present, high-sensitivity detection of pesticide residues, illegal additives, antibiotic residues, toxic pollutants in the environment and the like in foods is realized by utilizing the SERS technology, and important application prospects are shown in the fields of food safety, environmental monitoring, biological medicine and the like.
In order to realize the measurement of Raman spectrum, three types of Raman spectrum detection systems, namely a large-scale microscopic confocal Raman spectrometer, a portable Raman spectrometer and a handheld Raman spectrometer, are sequentially proposed. In the optical systems, a CCD spectrometer is adopted to collect Raman spectrum, and a dichroic mirror is used to separate Raman excitation light from Raman signal light. However, on one hand, the CCD spectrometer is expensive, the CCD price in the large-scale Raman spectrometer is hundreds of thousands yuan, and the small-scale CCD price in the portable Raman spectrometer is tens of thousands yuan, which is not beneficial to popularization and application; on the other hand, the spatial light Raman excitation and coupling mode based on the dichroic mirror increases the complexity of the system and is unfavorable for liquid phase in-situ detection application. Therefore, how to develop a low-cost and compact liquid-phase SERS spectrum detection system and technology becomes a key for popularization and application of the current SERS technology.
Disclosure of Invention
In order to better solve the problems, the invention provides a low-cost surface-enhanced Raman spectrum detection method, a system and a storage medium, so as to realize low-cost and compact liquid-phase SERS spectrum detection.
As a preferred technical scheme of the invention, the low-cost surface-enhanced Raman spectrum detection method comprises the following steps:
step S1: respectively arranging a laser and an object to be detected at two ends of an optical fiber, defining the end face of the optical fiber far away from the laser as a detection end face, and preparing a noble metal nanoparticle structure on the detection end face to form an optical fiber SERS probe, wherein SERS represents surface enhanced Raman scattering;
step S2: selecting a Raman characteristic peak based on a first graph of the SERS spectrum of the object to be detected, and calculating the center wavelength of the Raman characteristic peakAnd bandwidth->；
Step S3: center wavelength based on the raman characteristic peakAnd bandwidth->Preparing a fiber grating structure on an optical fiber, wherein the fiber grating is positioned between the laser and the detection end surface;
step S4: opening the laser, enabling the laser to emit Raman excitation light, enabling the Raman excitation light to reach the detection end face along an optical fiber, enabling the optical fiber SERS probe of the detection end face to excite the object to be detected, collecting SERS spectra of the object to be detected, enabling the optical fiber SERS probe to transmit the SERS spectra of the object to be detected back to the optical fiber grating through the optical fiber, enabling the optical fiber grating to reflect the SERS spectra of the object to be detected meeting the first condition to an optical notch filter, and extracting Raman characteristic peaks of the SERS spectra of the object to be detected, and enabling the SERS spectra of the object to be detected meeting the first condition to be called target SERS spectra;
step S5: the target SERS spectrum passes through the optical notch filter and then reaches an intensity detector, the intensity detector acquires the intensity data of the target SERS spectrum, and the concentration data of the object to be detected is calculated based on the intensity data of the target SERS spectrum.
As a preferable embodiment of the present invention, in the step S1, the optical fiber SERS probe is formed by any one of a laser induction method, a chemical modification fixing method and a template transfer method.
As a preferable technical scheme of the invention, the fiber bragg grating structure is prepared on the optical fiber by using a femtosecond laser direct writing technology.
As a preferred embodiment of the present invention, the laser is typically a narrow-band semiconductor laser, and the optical notch filter has an optical density greater than 6.
As a preferable technical scheme of the invention, the parameters of the fiber bragg grating structure are that the center wavelength of the reflection peak of the Raman spectrumBandwidth->Is greater than->Wherein->Is greater than->The magnitude of (2) does not exceed the first threshold.
As a preferred technical solution of the present invention, in the step S4, the SERS spectrum of the object to be measured that meets the first condition means that the SERS spectrum of the object to be measured falls into the bandwidth of the fiber bragg grating when being transmitted back to the fiber bragg gratingSERS spectra of the test object in the range.
As a preferred embodiment of the present invention, calculating the concentration data of the analyte based on the intensity data of the target SERS spectrum includes:
and calculating and establishing a concentration data relation between the intensity data of the target SERS spectrum and the object to be detected based on a least square method, and matching corresponding concentration data based on the intensity data after acquiring the intensity data of the target SERS spectrum.
The invention also provides a low-cost surface-enhanced Raman spectrum detection system, which comprises:
the laser is positioned at one end of the optical fiber and is used for providing Raman excitation light;
the optical fiber SERS probe is positioned at one end of the optical fiber far away from the laser and is formed by preparing noble metal nano particles on the end face of the optical fiber;
the optical fiber grating is positioned between the laser and the detection end surface and is used for reflecting the SERS spectrum of the object to be detected meeting the first condition to the optical notch filter;
the optical notch filter is used for collecting SERS spectra of the object to be detected meeting the first condition;
and the intensity detector is used for acquiring the intensity data of the target SERS spectrum.
The present invention also provides a computing device, the device comprising:
a memory and a processor;
the memory is configured to store computer-executable instructions that, when executed by the processor, implement the low cost surface enhanced raman spectrum detection method described above.
The invention also provides a storage medium storing computer executable instructions which when executed by a processor implement the low cost surface enhanced raman spectrum detection method described above.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the technical scheme, the optical fiber SERS probe is prepared to transmit the SERS spectrum of the object to be detected back to the optical fiber grating, the optical fiber grating reflects the SERS spectrum of the object to be detected meeting the first condition to the optical notch filter, and the optical fiber grating reaches the intensity detector after passing through the optical notch filter. The CCD spectrometer in the traditional spectrum detection system is replaced by the low-cost miniaturized intensity detector, so that the Raman spectrum detection is simplified into intensity detection of Raman characteristic peaks, and the cost of Raman detection is greatly reduced.
2. According to the technical scheme, the Raman excitation light is emitted by the laser and reaches the detection end face along the optical fiber, the optical fiber SERS probe of the detection end face excites an object to be detected, the SERS spectrum of the object to be detected is collected, the optical fiber SERS probe transmits the SERS spectrum of the object to be detected back to the optical fiber grating by the optical fiber, the space optical coupling mode based on the dichroic mirror is replaced by the optical fiber waveguide and the back transmission mode, on one hand, the separation of Raman signal light and Raman excitation light near a Raman characteristic peak is realized by the optical fiber grating, and an optical system is simplified; on the other hand, the optical fiber SERS probe is inserted into the solution to be detected, so that the liquid-phase in-situ detection of the SERS spectrum is easy to realize.
3. According to the technical scheme, the noble metal nanoparticle structure is directly prepared on the end face of the optical fiber to form the optical fiber SERS probe, and the optical fiber grating is prepared on the optical fiber, so that the optical fiber has the light splitting triple functions of the light transmission channel, the SERS sensitive unit and the Raman excitation light/SERS signal light, a coupling system is effectively simplified, and the optical fiber has important popularization and application prospects.
Drawings
FIG. 1 is a flow chart showing the steps of a low cost surface enhanced Raman spectrum detection method according to the present invention;
FIG. 2 is a schematic diagram of a low cost surface enhanced Raman spectroscopy detection method according to the present invention;
FIG. 3 is a block diagram of a low cost surface enhanced Raman spectrum detection system according to the present invention;
shown in fig. 3: 1. a laser; 2. an optical fiber SERS probe; 3. an optical fiber grating; 4. an optical notch filter; 5. an intensity detector; 6. an object to be measured.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
In the existing optical system, a CCD spectrometer is adopted to collect Raman spectrum, and a dichroic mirror is used to separate Raman excitation light from Raman signal light. However, the spectrometer adopted in the technical scheme is high in price, and liquid-phase Raman detection is difficult, so that inconvenience is brought to popularization and application.
In view of the above problems, the inventors propose a low-cost surface-enhanced raman spectrum detection method as shown in fig. 1, comprising the steps of:
step S1: respectively arranging a laser and an object to be detected at two ends of an optical fiber, defining the end face of the optical fiber far away from the laser as a detection end face, and preparing a noble metal nanoparticle structure on the detection end face to form an optical fiber SERS probe, wherein SERS represents surface-enhanced Raman scattering;
step S2: selecting a Raman characteristic peak based on a first graph of SERS spectrum of the object to be detected, and calculating the center wavelength of the Raman characteristic peakAnd bandwidth->；
Step S3: center wavelength based on Raman characteristic peakAnd bandwidth->Preparing a fiber grating structure on the optical fiber, wherein the fiber grating is positioned between the laser and the detection end surface;
step S4: opening a laser, enabling the laser to emit Raman excitation light, enabling the Raman excitation light to reach a detection end face along an optical fiber, enabling an optical fiber SERS probe of the detection end face to excite an object to be detected, collecting SERS spectra of the object to be detected, enabling the optical fiber SERS probe to transmit the SERS spectra of the object to be detected back to an optical fiber grating through the optical fiber, enabling the optical fiber grating to reflect the SERS spectra of the object to be detected meeting a first condition to an optical notch filter, extracting Raman characteristic peaks of the SERS spectra of the object to be detected, and enabling the SERS spectra of the object to be detected meeting the first condition to be called target SERS spectra;
step S5: the target SERS spectrum passes through the optical notch filter and then reaches the intensity detector, the intensity detector acquires the intensity data of the target SERS spectrum, and the concentration data of the object to be detected is calculated based on the intensity data of the target SERS spectrum.
Specifically, by converting the spectrum measurement into the intensity measurement and combining the waveguide transmission characteristic of the optical fiber and the filtering characteristic of the optical fiber device, the optical system is greatly simplified, the cost is reduced, and a new way is provided for solving the main problems of difficult liquid-phase Raman detection, high price of the spectrometer and unfavorable popularization and application faced by the current SERS spectrum technology. More specifically, as shown in fig. 3, a noble metal nanoparticle structure is prepared on the end surface of the optical fiber far away from the laser, so as to form an optical fiber SERS probe. It is also possible to prepare a noble metal nanoparticle structure on the side or inside of the fiber, where noble metal refers to gold or silver. SERS is surface enhanced Raman scattering (surface-enhanced Raman scattering), abbreviated as SERS, and the principle is to enhance Raman scattering signals of an object to be detected by utilizing the surface plasmon resonance effect of metal nanoparticles. When the laser irradiates the surface of the object to be detected, part of molecules are absorbed by the object to be detected, and the other part of photons are scattered. Some of these scattered photons will be absorbed by the metal nanoparticles, creating a surface plasmon resonance effect. This effect results in an increase in electron density at the surface of the metal nanoparticle, thereby enhancing the raman scattering signal of the analyte. The SERS technique has the advantage of improving the sensitivity and resolution of detection. Due to the surface enhancement effect of the metal nanoparticles, the raman scattering signal of the object to be detected can be enhanced hundreds of times or even thousands of times, so that very weak signals can be detected. In addition, since the size of the metal nanoparticles is very small, it is possible to reach a nano-scale, and thus resolution can be improved, and finer structures and chemical components can be detected. Because of this, SERS technology is widely used in many fields. The above-mentioned test substances may be liquids, solids and powders.
As shown in fig. 2, from the SERS spectrum graph of the sample, fig. 2 (a), the raman characteristic peak is extracted, fig. 2 (b), and the center wavelength of the raman characteristic peak is calculatedAnd bandwidth->Preparing a fiber grating structure on an optical fiber, setting parameter values of the fiber grating structure to enable center wavelength of a reflection peak of a Raman signal to be +.>Bandwidth->Slightly greater than->Bandwidth->Is greater than->The magnitude of (2) cannot exceed a preset first threshold. The function of preparing a fiber grating structure on an optical fiber is to form a narrow band (transmissive or reflective) filter or mirror within the fiber core. When a beam of broad spectrum light passes through the fiber bragg grating, wavelengths meeting the Bragg condition of the fiber bragg grating are reflected, and the rest wavelengths continue to be transmitted through the fiber bragg grating. The specific preparation method of the fiber bragg grating belongs to common general knowledge and is not described in detail herein.
In the established low-cost surface-enhanced Raman spectrum detection system, a laser is turned on, the laser emits Raman excitation light, the Raman excitation light reaches the detection end face along the optical fiber, and the optical fiber SERS probe of the detection end face excites an object to be detected, namely molecules to be detected adsorbed on the surface of the optical fiber SERS probe in the object to be detected can be excited. Collecting SERS spectrum of the object to be detected, and returning the SERS spectrum of the object to be detected to the fiber grating to fall into the bandwidth of the fiber gratingThe SERS spectrum of the object to be detected in the range is mostly reflected to the receiving light path, while other SERS spectrums continue to be transmitted through the fiber grating and fall into the bandwidth of the fiber grating>SERS spectra of the analyte in the range, i.e. the raman characteristic peaks mentioned in the above text; after the extracted Raman characteristic peak passes through the optical notch filter, the intensity detector obtains the intensity data of the SERS spectrum. The intensity of the SERS spectrum is the same as that to be obtainedThe concentration of the measured object is closely related, the relationship between the intensity data of the SERS spectrum of the measured object and the concentration data of the measured object is established based on a least square method, and after the intensity data of the target spectrum is acquired, the corresponding concentration data is matched based on the intensity data. Thereby realizing the quantitative detection of the object to be detected. The least square method is common knowledge and will not be described in detail here.
Further, the step S1 further includes a preparation method of the optical fiber SERS probe, and the preparation method at least includes a laser induction method, a chemical modification fixing method and a template transfer method.
Specifically, the preparation method of the optical fiber SERS probe comprises a laser induction method, a chemical modification fixing method and a template transfer method, and the three methods are respectively as follows: the laser induction method focuses the laser beam on the surface of the optical fiber, and utilizes the laser energy to locally treat the surface of the optical fiber to form the SERS active substrate. Commonly used lasers include ultraviolet lasers, blue lasers, and the like. The method is simple to operate, but is critical to control of laser power and focusing position, and is easy to damage the surface of the optical fiber. Chemical modification immobilization involves introducing chemical modification groups to the surface of the fiber and then immobilizing SERS-active particles on the surface of the fiber by chemical bonding or adsorption. Common chemical modifying groups include thiols, silanes, and the like. This method can control the distribution and density of SERS-active particles, but requires a certain degree of chemical knowledge and experimental skill. Template transfer methods by preparing template structures such as nanopore arrays or nanowire arrays on the surface of the fiber and then filling SERS-active particles into the holes. The method can control the position and arrangement mode of SERS active particles, thereby obtaining the SERS probe with high stability and high sensitivity. But requires equipment and techniques for preparing the template structures, as well as controlling the size and density of SERS-active particles.
Further, a fiber grating structure is fabricated on the fiber using a femtosecond laser direct writing technique.
Specifically, the femtosecond laser direct writing technique is a method of directly generating a microstructure inside or on the surface of a material using high energy pulses of a femtosecond laser. This technique can produce various micro-nanostructures such as fiber gratings, micro-optics, microfluidic chips, and the like. The femtosecond laser direct writing technology has the advantages of high precision, high efficiency, non-contact performance, no mask and the like, and is widely applied to the micro-nano processing field. The principle of the femtosecond laser direct writing technology is that the high-energy pulse of the femtosecond laser is utilized to locally heat the material to a high-temperature state, and the phenomena of evaporation and plasma are generated instantaneously to form the micro-nano structure. The dimensions of these structures can be controlled on the order of nanometers to micrometers and can be designed and manufactured as desired. Meanwhile, the femtosecond laser direct writing technology can also control parameters such as pulse energy, frequency, scanning speed and the like so as to further optimize the manufacturing effect. In the aspect of preparing the fiber grating, the femtosecond laser direct writing technology can manufacture a structure with periodic refractive index change in the interior or the surface of the fiber, so as to form the grating. The grating can be used in the fields of wavelength selection, sensors, optical fiber communication and the like. By adjusting the parameters of the femtosecond laser, fiber grating structures with different shapes and sizes can be manufactured to meet different application requirements.
Further, the laser is typically a narrow-band semiconductor laser, and the optical notch filter has an optical density greater than 6.
In particular, the laser is typically a narrow-band semiconductor laser for providing raman excitation light; the optical notch filter is used for realizing narrow-band filtering of the Raman excitation light in the collecting light path, in particular, attenuating the light energy of the Raman excitation light wavelength range to a very low level, and the optical Density (optical Density) is generally greater than 6; but the light with other wavelengths is efficiently transmitted, and the transmittance is more than 90 percent. In application, the narrow-band raman excitation light can be transmitted to the fiber SERS probe through the fiber bragg grating, and excite the molecules adsorbed in the analyte on the surface of the probe. These molecules will generate strong raman signals, i.e. SERS spectra, under the influence of surface plasmon resonance. By analyzing the SERS spectrum, the chemical composition of the analyte can be determined, thereby allowing analysis and detection of the analyte.
The optical notch filter is an optical filter which forms a high-reflectivity stop band by utilizing the interference effect of the multilayer thin films, light in the stop band is reflected or absorbed, and light outside the stop band is transmitted. The filter can design different stop bands and passband according to different spectrum requirements so as to realize accurate control and adjustment of optical signals. In the optical notch filter, the interference effect of the multilayer film can realize the selective filtering of optical signals with different wavelengths. When an optical signal is transmitted to the filter, it is reflected or absorbed without passing through the filter if its wavelength is within the stop band range of the filter. If its wavelength is within the passband of the filter, it is transmitted and output on the other side of the filter. Therefore, the optical notch filter can be used in the fields of spectrum analysis, optical communication, optical sensing and the like. In SERS technology, an optical notch filter can be used to filter out backscattered SERS light within the bandwidth of the fiber grating, thereby avoiding its interference with SERS signals and improving signal-to-noise ratio and detection sensitivity.
Further, the parameters of the fiber grating structure are that the center wavelength of the reflection peak of the Raman spectrumBandwidth->Is greater than->Wherein->Is greater than->The magnitude of (2) does not exceed the first threshold.
Specifically, the parameter value of the fiber grating structure is designed as the center wavelength of the reflection peak of the Raman signalBandwidth ofSlightly greater than->Bandwidth->Is greater than->The magnitude of (2) cannot exceed a preset first threshold. The fiber grating is a fiber structure with periodic refractive index change, and can be used for reflection, transmission, light splitting and other applications of light waves. When the backscattered SERS light is transmitted to the fibre grating, it is reflected back and transmitted onto the optical notch filter if its spectral range is well within the bandwidth of the fibre grating. An optical notch filter is an optical filter with a specific wavelength selectivity that can be used to filter out optical signals of a specific wavelength. In such applications, the optical notch filter may filter out backscattered SERS light within the bandwidth of the fiber grating, thereby avoiding its interference with SERS signals and improving signal-to-noise ratio and detection sensitivity.
Further, in the step S4, the SERS spectrum of the object to be measured meeting the first condition means that the SERS spectrum of the object to be measured falls into the bandwidth of the fiber bragg grating when being transmitted back to the fiber bragg gratingSERS spectra of the test object in the range.
Specifically, when the SERS spectrum of the object to be detected is transmitted to the fiber grating, if the spectrum range thereof is exactly within the bandwidth of the fiber gratingWithin range, will be reflected back. This phenomenon, known as bragg scattering, is one of the basic principles of fiber gratings. In the SERS technology, the SERS spectrum of the analyte may be transmitted to a fiber grating through an optical fiber for analysis and detection. When the SERS spectrum is transmitted to the fiber grating, it is reflected back if its spectral range is well within the fiber grating bandwidth. The reflection spectrum contains the information of the object to be detected and can be communicated withProcessing by spectroscopic analysis technique.
Further, calculating concentration data of the analyte based on the intensity data of the target SERS spectrum includes:
and calculating and establishing a concentration data relation between the intensity data of the target SERS spectrum and the object to be detected based on a least square method, and matching corresponding concentration data based on the intensity data after acquiring the intensity data of the target SERS spectrum.
Specifically, because the intensity data of the SERS spectrum of the to-be-detected object is closely related to the concentration data of the to-be-detected object, the relationship between the intensity data of the SERS spectrum of the to-be-detected object and the concentration data of the to-be-detected object can be established by utilizing the least square method, the intensity data of the SERS spectrum of the to-be-detected object can be obtained by the method, and the concentration data of the to-be-detected object can be matched based on the intensity data of the SERS spectrum of the to-be-detected object, so that the concentration detection of the to-be-detected object can be realized.
The invention also provides a low-cost surface-enhanced Raman spectrum detection system as shown in FIG. 3, comprising:
a laser 1 located at one end of the optical fiber for providing raman excitation light;
the optical fiber SERS probe 2 is positioned at one end of the optical fiber far away from the laser and is formed by preparing noble metal nano particles on the end face of the optical fiber;
the fiber bragg grating 3 is positioned between the laser and the detection end surface and is used for reflecting the SERS spectrum of the object to be detected meeting the first condition to the optical notch filter;
an optical notch filter 4 for realizing collection of SERS spectra of the object to be measured satisfying the first condition;
an intensity detector 5 for acquiring intensity data of the target SERS spectrum.
A memory and a processor;
the memory is configured to store computer-executable instructions that, when executed by the processor, implement the low cost surface enhanced raman spectrum detection method described above.
The invention also provides a computer storage medium, wherein the storage medium stores program instructions, and the device where the computer storage medium is located is controlled to execute the low-cost surface-enhanced Raman spectrum detection method when the program instructions run.
In summary, by respectively arranging a laser and an object to be detected at two ends of an optical fiber, defining an end surface of the optical fiber far away from the laser as a detection end surface, and preparing a noble metal nanoparticle structure on the detection end surface to form an optical fiber SERS probe, wherein SERS represents surface enhanced Raman scattering; selecting a Raman characteristic peak based on a first graph of SERS spectrum of the object to be detected, and calculating the center wavelength of the Raman characteristic peakAnd bandwidth->The method comprises the steps of carrying out a first treatment on the surface of the Center wavelength based on Raman characteristic peak +.>And bandwidth->Preparing a fiber grating structure on the optical fiber, wherein the fiber grating is positioned between the laser and the detection end surface; opening a laser, enabling the laser to emit Raman excitation light, enabling the Raman excitation light to reach a detection end face along an optical fiber, enabling an optical fiber SERS probe of the detection end face to excite an object to be detected, collecting SERS spectra of the object to be detected, enabling the optical fiber SERS probe to transmit the SERS spectra of the object to be detected back to an optical fiber grating through the optical fiber, enabling the optical fiber grating to reflect the SERS spectra of the object to be detected meeting a first condition to an optical notch filter, extracting Raman characteristic peaks of the SERS spectra of the object to be detected, and enabling the SERS spectra of the object to be detected meeting the first condition to be called target SERS spectra; the target SERS spectrum passes through the optical notch filter and then reaches the intensity detector, the intensity detector acquires the intensity data of the target SERS spectrum, and the concentration data of the object to be detected is calculated based on the intensity data of the target SERS spectrum. The invention greatly simplifies the optical system, reduces the detection cost, and provides a new approach for solving the main problems of difficult liquid-phase Raman detection, expensive spectrometer price and unfavorable popularization and application faced by the current SERS spectrum technology.
The technical features of the above embodiments may be arbitrarily combined, and for brevity, all of the possible combinations of the technical features of the above embodiments are not described, however, they should be considered as the scope of the description of the present specification as long as there is no contradiction between the combinations of the technical features.
The foregoing examples have been presented to illustrate only a few embodiments of the invention and are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (10)
1. A low cost surface enhanced raman spectroscopy detection method, the method comprising the steps of:
step S1: respectively arranging a laser and an object to be detected at two ends of an optical fiber, defining the end face of the optical fiber far away from the laser as a detection end face, and preparing a noble metal nanoparticle structure on the detection end face to form an optical fiber SERS probe, wherein SERS represents surface enhanced Raman scattering;
step S2: selecting a Raman characteristic peak based on a first graph of the SERS spectrum of the object to be detected, and calculating the center wavelength of the Raman characteristic peakAnd bandwidth->；
Step S3: center wavelength based on the raman characteristic peakAnd bandwidth->Preparing a fiber grating structure on an optical fiber, wherein the fiber grating is positioned between the laser and the detection end surface;
step S4: opening the laser, enabling the laser to emit Raman excitation light, enabling the Raman excitation light to reach the detection end face along an optical fiber, enabling the optical fiber SERS probe of the detection end face to excite the object to be detected, collecting SERS spectra of the object to be detected, enabling the optical fiber SERS probe to transmit the SERS spectra of the object to be detected back to the optical fiber grating through the optical fiber, enabling the optical fiber grating to reflect the SERS spectra of the object to be detected meeting the first condition to an optical notch filter, and extracting Raman characteristic peaks of the SERS spectra of the object to be detected, and enabling the SERS spectra of the object to be detected meeting the first condition to be called target SERS spectra;
step S5: the target SERS spectrum passes through the optical notch filter and then reaches an intensity detector, the intensity detector acquires the intensity data of the target SERS spectrum, and the concentration data of the object to be detected is calculated based on the intensity data of the target SERS spectrum.
2. The method according to claim 1, wherein in the step S1, the optical fiber SERS probe is formed by any one of a laser induction method, a chemical modification fixing method and a template transfer method.
3. The method of claim 1, wherein the fiber grating structure is fabricated on the optical fiber using a femtosecond laser direct write technique.
4. The method of claim 1, wherein the laser is a narrow band semiconductor laser and the optical notch filter has an optical density greater than 6.
5. The method of claim 1, wherein the parameters of the fiber grating structure are such that the center wavelength of the reflection peak of the raman spectrumBandwidth->Is greater than->Wherein->Greater thanThe magnitude of (2) does not exceed the first threshold.
6. The method according to claim 1, wherein in the step S4, the SERS spectrum of the object to be measured satisfying the first condition means that the SERS spectrum of the object to be measured falls into the bandwidth of the fiber bragg grating when being transmitted back to the fiber bragg gratingSERS spectra of the test object in the range.
7. The method of claim 1, wherein calculating concentration data of the test object based on intensity data of the target SERS spectrum comprises:
and calculating and establishing a concentration data relation between the intensity data of the target SERS spectrum and the object to be detected based on a least square method, and matching corresponding concentration data based on the intensity data after acquiring the intensity data of the target SERS spectrum.
8. A low cost surface enhanced raman spectroscopy detection system for implementing the method of any one of claims 1-7, said system comprising:
the laser is positioned at one end of the optical fiber and is used for providing Raman excitation light;
the optical fiber SERS probe is positioned at one end of the optical fiber far away from the laser and is formed by preparing noble metal nano particles on the end face of the optical fiber;
the optical fiber grating is positioned between the laser and the detection end surface and is used for reflecting the SERS spectrum of the object to be detected meeting the first condition to the optical notch filter;
the optical notch filter is used for collecting SERS spectra of the object to be detected meeting the first condition;
and the intensity detector is used for acquiring the intensity data of the target SERS spectrum.
9. A computing device, the device comprising:
a memory and a processor;
the memory is for storing computer executable instructions that, when executed by the processor, implement the low cost surface enhanced raman spectrum detection method of any one of claims 1 to 7.
10. A computer storage medium, characterized in that the storage medium stores program instructions, wherein the program instructions, when run, control a device in which the storage medium is located to perform the low cost surface enhanced raman spectroscopy detection method of any one of claims 1 to 7.
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