CN111912524B - Raman spectroscopy imaging method and imaging device - Google Patents

Abstract

The invention relates to a Raman spectrum imaging device, which belongs to the technical field of spectrum imaging, wherein in the prior art, corresponding objective lenses are not specially designed for different substrates; the method has wide application, can be selected according to the characteristics of the detection object, and can also be used for comparison and scientific research.

Description

Raman spectroscopy imaging method and imaging device

technical field

The invention relates to the technical field of spectral imaging, in particular to a Raman spectral imaging device.

Background technique

Raman spectroscopy is a type of scattering spectroscopy discovered by Indian scientist C.V. Raman. Based on the Raman scattering effect, it is of great value to analyze the scattering spectrum with different frequencies from the incident light to obtain information on molecular vibration and rotation, and to apply it to the study of molecular structure.

However, the Raman scattering effect is a very weak process, so the Raman signal is very weak, and Raman spectroscopy studies of surface adsorbed species almost always use some kind of enhancement effect. In the prior art, the most common surface-enhanced Raman spectroscopy effect, the substrate of surface-enhanced Raman spectroscopy is the key technology, roughly including nanoparticle substrates, nanowire substrates, etc. The enhancement mechanism and enhancement effect between different substrates. There are significant differences between them, and there is no optical system specifically provided for these differences in the prior art.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the present invention provides a Raman spectroscopy imaging method, characterized in that: the method comprises the following steps:

Step (1) placing the detection object on the nanowire array substrate and the nanoparticle substrate respectively;

Step (2) When the nanowire array substrate is selected, the light emitted by the light source passes through the nanowire array substrate, the first objective lens and the imaging unit in sequence; when the nanoparticle substrate is selected, the light emitted by the light source sequentially passes through the nanoparticle substrate , a second objective lens and the imaging unit;

In step (3), the imaging unit transmits the image information to the host computer for comparative analysis;

Wherein, the first objective lens includes, from the object side to the image side, a first cemented lens composed of a first lens with positive refractive power and a second lens with negative refractive power, a third lens with positive refractive power and a fourth lens with negative refractive power composed of a second cemented lens and a fifth lens of negative diopter;

and satisfy d ₁ /TTL>0.45, wherein d ₁ is the radius of the first lens, and TTL is the total optical length of the first objective lens;

The second objective lens sequentially includes a third cemented lens composed of a sixth lens with positive refractive power and a seventh lens with negative refractive power, and an eighth lens with positive refractive power and a ninth lens with negative refractive power in sequence from the object side to the image side. the fourth cemented lens and the tenth lens of negative diopter;

The field of view angle θ of the second objective lens satisfies 110°>θ>70°, and the numerical aperture of the second objective lens NA>0.6.

Preferably, the first objective lens satisfies the following conditions: 1.9>f ₁ /f ₄₀ >1.2;

3.7>f ₁ /f ₂ >1.1;

5.1>f ₁ /f ₃ >2.4;

The focal length of the first cemented lens is f ₁ , the focal length of the second cemented lens is f ₂ , the focal length of the fifth lens is f ₃ , and the total focal length of the first objective lens is f ₄₀ .

Preferably, the second objective lens satisfies the following conditions: 1.7>f ₅ /f ₆₀ >1.3;

2.7>f ₆ /f ₆₀ >1.5;

-1.2>f ₇ /f ₆₀ >-1.6;

The focal length of the third cemented lens is f ₅ , the focal length of the fourth cemented lens is f ₆ , the focal length of the tenth lens is f ₇ , and the total focal length of the second objective lens is f ₆₀ .

The present invention also provides a Raman spectrum imaging device, characterized in that: the device comprises a laser light source, a contrast selection unit, a first substrate, a first objective lens, a second substrate, a second objective lens and an imaging unit;

When the contrast selection unit selects the first substrate, the light emitted by the light source passes through the first substrate, the first objective lens and the imaging unit in sequence; wherein the first substrate is a nanowire array substrate;

When the contrast selection unit selects the second substrate, the light emitted by the light source passes through the second substrate, the second objective lens and the imaging unit in sequence; wherein the second substrate is a nanoparticle substrate;

The first objective lens includes, in order from the object side to the image side, a first cemented lens composed of a first lens with positive refractive power and a second lens with negative refractive power, a third lens with positive refractive power and a fourth lens with negative refractive power. The second cemented lens and the fifth lens of negative refractive power;

and satisfy d ₁ /TTL>0.45, wherein d ₁ is the radius of the first lens, and TTL is the total optical length of the first objective lens;

The second objective lens sequentially includes a third cemented lens composed of a sixth lens with positive refractive power and a seventh lens with negative refractive power, and an eighth lens with positive refractive power and a ninth lens with negative refractive power in sequence from the object side to the image side. the fourth cemented lens and the tenth lens of negative diopter;

The field of view angle θ of the second objective lens satisfies 110°>θ>70°, and the numerical aperture of the second objective lens NA>0.6.

Preferably, both the first substrate and the second substrate are located on a sample stage, the sample stage can be rotated to replace the first substrate and the second substrate, and the sample stage can also be used in X, Fine-tune in three directions of Y and Z.

Compared with the prior art solutions, the present invention at least has the following invention points and corresponding beneficial effects:

(1) According to the different characteristics of the nanowire substrate and the nanoparticle substrate, the present invention designs two groups of objective lenses. The user can select or compare according to the different characteristics of the object and the substrate. The device has a wide range of applications. Compared with the prior art, the present invention has specially designed the objective lens for the comparison of nanowires and nanoparticles. This design includes the transformation of two targeted objectives, using a rotating mechanism suitable for rapid switching. The rotating mechanism can quickly switch to the objective lens required for the second substrate after the detection of the first substrate is completed, which is very important in the detection of nanowires and nanoparticles. Because the nanowires and nanoparticles need to be tested quickly after the preparation is completed, the time is prolonged, and there is a risk of introducing impurities before packaging, which affects the detection accuracy. Therefore, using, for example, a rotating mechanism, the rotating component can be used to quickly switch to the desired objective lens, so as to meet the needs of the above detection.

(2) The design and specific parameters of the specific lens of the first objective lens group can maximize the advantage of the large effective aperture of the nanowire substrate.

(3) The specific lens design and specific parameters of the second objective lens group are aimed at improving the resolution of the nanoparticle substrate and suppressing the defects of the substrate as much as possible.

It should be pointed out that this objective lens is specially designed for Raman spectroscopy, and cannot be replaced by objective lenses in other fields. This is because Raman spectroscopy has its own characteristics, and it needs to adapt to a wide range of wavelengths and at the same time meet the requirements of imaging. In addition, the large scattering angle of Raman light requires a large numerical aperture of the objective lens. The above-mentioned but not limited to the above-mentioned characteristics determine that the objective lens needs to be specially customized, and not a general-purpose objective lens can meet the requirements of substrate detection.

Description of drawings

1 is a frame diagram of a Raman spectroscopy imaging device provided by the present invention;

Fig. 2 is the structure diagram of the first objective lens group of the present invention;

Fig. 3 is the field curvature and distortion diagram of the first objective lens of the present invention;

Fig. 4 is the first objective lens chromatic aberration diagram of the present invention;

Fig. 5 is the structure diagram of the second objective lens group of the present invention;

Fig. 6 is the field curvature and distortion diagram of the second objective lens of the present invention;

Fig. 7 is the chromatic aberration diagram of the second objective lens of the present invention;

In the figure: 10, laser light source, 20, contrast selection unit, 30, first substrate, 40, first objective lens, 50, second substrate, 60, second objective lens, 70, CCD imaging unit, 80, host computer, 11 , the first lens of the first objective lens, 12, the second lens of the first objective lens, 13, the third lens of the first objective lens, the first objective lens 21, the fourth lens of the first objective lens, 3, the fifth lens of the first objective lens, 51, the first Two objective lenses, the first lens, 52, the second lens of the second objective, 61, the third lens of the second objective, 62, the fourth lens of the second objective, and 7, the fifth lens of the second objective.

The present invention will be described in further detail below. However, the following examples are only simple examples of the present invention, and do not represent or limit the protection scope of the present invention. The protection scope of the present invention is subject to the claims.

Detailed ways

The technical solutions of the present invention are further described below with reference to the accompanying drawings and through specific embodiments.

In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, typical but non-limiting examples of the present invention are as follows:

Example 1

In this embodiment, as shown in FIG. 1 , the Raman spectral imaging device includes a laser light source 10 , a contrast selection unit 20 , a first substrate 30 , a first objective lens 40 , a second substrate 50 , a second objective lens 60 , and a CCD imaging unit 70 and the host computer 80.

When the comparison selection unit 20 selects the first substrate 30 to carry the sample, the light emitted by the laser light source 10 passes through the first substrate 30, then passes through the first objective lens 40 in turn, and finally the light reaches the CCD imaging unit, and transmits the image information to the upper position. machine for storage;

When the comparison selection unit 20 selects the second substrate 50 to carry the sample, the light emitted by the laser light source 10 passes through the second substrate 50, then passes through the second objective lens 60 in turn, and finally the light reaches the CCD imaging unit, and transmits the image information to the host computer to store.

It should be pointed out that after the detection of the first substrate 30 is completed, the objective lens can be quickly switched from the first objective lens 40 to the second objective lens 60 by using an objective lens conversion device such as a rotating mechanism, which is especially suitable for newly prepared substrates that require rapid detection. In this way, the risk of introducing impurities into the base material before encapsulation due to waiting for the commissioning of the second objective lens 60 can be avoided.

The contrast selection unit 20 can select the first objective lens 40 or the second objective lens 60 according to the specific properties of the detected material and the characteristics of the nanowire substrate and the nanoparticle substrate. Detected under two objective lenses 60, and further scientific research on the detected object and base material.

The first substrate 30 is a high-quality metal nanowire array formed on a silicon substrate, wherein the metal can be a precious metal such as gold, silver or copper; wherein the nanowire is a regular periodic structure, when the wavelength of the laser light source used is slightly Greater than the period of the above nanowire, the energy of the incident point light source is coupled to the surface plasmon wave, and the outgoing effective aperture stop is significantly increased.

Corresponding to the first substrate 30, the specially designed first objective lens 40 is specifically as follows: from the object side to the image side, it includes a first lens 11 with a positive refractive index, a second lens 12 with a negative refractive index, and a third lens with a positive refractive index. lens 21, fourth lens 22 with negative refractive index, fifth lens 3 with negative refractive index; wherein the first lens 11 and the second lens 12 are cemented lenses, the third lens 21 and the fourth lens 22 are cemented lenses, Among them, the cemented lens formed by the combination of two positive and negative lenses minimizes chromatic aberration; the parameters of each lens are as follows:

Table 1: Nanowire Substrate Objective Lens Parameters

As shown in Figure 3, the field curvature and distortion diagram of the first objective lens of the present invention;

As shown in Figure 4, the chromatic aberration diagram of the first objective lens of the present invention;

In addition, the lens radius of the first lens 11 and the second lens 12 is d1, the total length of the optical system of the first objective lens is TTL, and d ₁ /TTL>0.45, so that the first objective lens has a larger effective aperture. In this embodiment , the lens radius d ₁ of the first lens 11 and the second lens 12 is 5mm, and the total length of the optical system is TTL of 9mm;

In the first objective lens, the focal length of the cemented lens composed of the first lens 11 and the second lens 12 is f ₁ , the focal length of the cemented lens composed of the third lens 21 and the fourth lens 22 is f ₂ , and the focal length of the fifth lens 3 is f _3. The total focal length of the first objective lens is f ₄₀ , and the above focal lengths satisfy the following relationship:

1.9>f ₁ /f ₄₀ >1.2;

3.7>f ₁ /f ₂ >1.1;

5.1>f ₁ /f ₃ >2.4.

Wherein the second substrate 50 is a high-quality nanoparticle film formed on a silicon substrate, wherein the metal can be a precious metal such as gold, silver or copper; due to the small size of the nanoparticles, only the electric dipole resonance mode will occur. In the case, an SPR peak appears on the spectrum. When the size of the particles increases, the SPR peak redshifts, and new high-order SPR peaks appear in the short-wave region, but, in general, these resonance peaks have a comparable spectral width, They will overlap with each other, and their respective proportions are difficult to distinguish. In some special cases, some formants are not easy to identify their physical origins.

Corresponding to the second substrate 50, the specially designed second objective lens 60 is as follows:

The specially designed second objective lens is as follows: from the object side to the image side, it sequentially includes a first lens 51 with a positive refractive index, a second lens 52 with a negative refractive index, a third lens 61 with a positive refractive index, and a negative refractive index lens 61. The fourth lens 62, the fifth lens 7 having a negative refractive index; wherein the first lens 51 and the second lens 52 are cemented lenses, the third lens 61 and the fourth lens 62 are cemented lenses, wherein through two positive and negative lenses The combined cemented lens minimizes chromatic aberration; the parameters of each lens are as follows:

Table 2: Nanoparticle Substrate Objective Lens Parameters

As shown in Figure 6, the field curvature and distortion diagram of the second objective lens of the present invention;

As shown in Figure 7, the chromatic aberration diagram of the second objective lens of the present invention;

The field angle θ of the second objective lens satisfies, 110°>θ>70°, and the numerical aperture of the second objective lens NA>0.6, so that the lens group has high resolution;

In the second objective lens, the focal length of the cemented lens composed of the first lens 51 and the second lens 52 is f ₅ , the focal length of the cemented lens composed of the third lens 61 and the fourth lens 62 is f ₆ , and the focal length of the fifth lens 7 is f _7. The total focal length of the second objective lens is f ₆₀ , and the above focal lengths satisfy the following relationship:

1.7>f ₅ /f ₆₀ >1.3;

2.7>f ₆ /f ₆₀ >1.5;

-1.2>f ₇ /f ₆₀ >-1.6.

In the above spectroscopic imaging device, both the first substrate and the second substrate are located on a sample stage (not shown in the figure), the sample stage can be rotated to replace the first substrate and the second substrate, and the sample stage can also In the three directions of X, Y, and Z, it can be fine-tuned according to the needs of the user to cope with the different focal lengths of different objective lenses and/or to align and adjust the angle of the test sample.

The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of the selected components of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the specific technical features described in the above-mentioned specific embodiments can be combined in any suitable manner unless they are inconsistent. In order to avoid unnecessary repetition, the present invention provides The combination method will not be specified otherwise.

In addition, the various embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the contents disclosed in the present invention.

Claims (3)

1. A Raman spectrum imaging method is characterized in that: the method comprises the following steps:

respectively placing detection objects on a nanowire array substrate and a nanoparticle substrate;

when the nanowire array substrate is selected, light emitted by a light source sequentially passes through the nanowire array substrate, a first objective lens and an imaging unit; when the nanoparticle substrate is selected, light emitted by the light source sequentially passes through the nanoparticle substrate, the second objective lens and the imaging unit;

the imaging unit transmits the image information to an upper computer for comparison and analysis;

the first objective lens comprises a first cemented lens consisting of a first lens with positive diopter and a second lens with negative diopter, a second cemented lens consisting of a third lens with positive diopter and a fourth lens with negative diopter and a fifth lens with negative diopter in sequence from the object space to the image space;

and satisfy d ₁ /TTL>0.45, wherein d ₁ TTL is the optical total length of the first objective lens and is the radius of the first lens;

the second objective lens sequentially comprises a third cemented lens consisting of a sixth lens with positive diopter and a seventh lens with negative diopter, a fourth cemented lens consisting of an eighth lens with positive diopter and a ninth lens with negative diopter and a tenth lens with negative diopter from the object side to the image side;

the field angle theta of the second objective lens meets the condition that 110 degrees > theta >70 degrees, and the numerical aperture NA of the second objective lens is >0.6;

the first objective lens satisfies the following condition: 1.9>f ₁ /f ₄₀ >1.2；

3.7>f ₁ /f ₂ >1.1；

5.1>f ₁ /f ₃ >2.4；

Wherein the focal length of the first cemented lens is f ₁ The focal length of the second cemented lens is f ₂ A focal length f of the fifth lens ₃ The total focal length of the first objective lens is f ₄₀ ；

The second objective lens satisfies the following conditions: 1.7>f ₅ /f ₆₀ >1.3；

2.7>f ₆ /f ₆₀ >1.5；

-1.2>f ₇ /f ₆₀ >-1.6；

Wherein the third cemented lens has a focal length f ₅ A focal length f of the fourth cemented lens ₆ A focal length of the tenth lens is f ₇ The total focal length of the second objective lens is f ₆₀ 。

2. A raman spectral imaging device characterized by: the device comprises a laser light source, a contrast selection unit, a first substrate, a first objective lens, a second substrate, a second objective lens and an imaging unit;

when the contrast selection unit selects a first substrate, light emitted by the light source sequentially passes through the first substrate, the first objective lens and the imaging unit; wherein the first substrate is a nanowire array substrate;

when the contrast selection unit selects a second substrate, light emitted by the light source sequentially passes through the second substrate, the second objective lens and the imaging unit; wherein the second substrate is a nanoparticle substrate;

the first objective lens comprises a first cemented lens consisting of a first lens with positive diopter and a second lens with negative diopter, a second cemented lens consisting of a third lens with positive diopter and a fourth lens with negative diopter and a fifth lens with negative diopter in sequence from the object space to the image space;

and satisfy d ₁ /TTL>0.45, wherein d ₁ The radius of the first lens is defined, and TTL is the total optical length of the first objective lens;

the second objective lens sequentially comprises a third cemented lens consisting of a sixth lens with positive diopter and a seventh lens with negative diopter, a fourth cemented lens consisting of an eighth lens with positive diopter and a ninth lens with negative diopter and a tenth lens with negative diopter from the object space to the image space;

the field angle theta of the second objective lens meets the condition that 110 degrees > theta >70 degrees, and the numerical aperture NA of the second objective lens is >0.6;

the first objective lens satisfies the following condition: 1.9>f ₁ /f ₄₀ >1.2；

3.7>f ₁ /f ₂ >1.1；

5.1>f ₁ /f ₃ >2.4；

Wherein, the first stepA cemented lens having a focal length of f ₁ The focal length of the second cemented lens is f ₂ A focal length f of the fifth lens ₃ The total focal length of the first objective lens is f ₄₀ ；

The second objective lens satisfies the following conditions: 1.7>f ₅ /f ₆₀ >1.3；

2.7>f ₆ /f ₆₀ >1.5；

-1.2>f ₇ /f ₆₀ >-1.6；

Wherein the third cemented lens has a focal length f ₅ A focal length f of the fourth cemented lens ₆ A focal length of the tenth lens is f ₇ The total focal length of the second objective lens is f ₆₀ 。

3. The apparatus of claim 2, wherein: the first base and the second base are both positioned on a sample stage, the first base and the second base can be replaced by the sample stage through rotation, and the sample stage can be finely adjusted in three directions of X, Y and Z.

Images