Particle sorting mechanism

Abstract

The particle sorting mechanism of the present application has: a flow path in which a plurality of first nano-particles having an absorber having a given absorption energy level and a plurality of second nano-particles not having an absorber having a given absorption energy level exist, and having a first input portion and a second input portion; a laser that outputs first light in a direction from the first input portion toward the second input portion, the first light being absorbed by the absorber having a given absorption energy level; and a laser that outputs second light in a direction from the second input portion toward the first input portion, the second light not being absorbed by the absorber having a given absorption energy level, and the second nano-particles being scattered or absorbed.

Description

Technical Field

[0001] One aspect of the present invention relates to a particle sorting mechanism. Background Technology

[0002] Methods for separating particles include, for example, centrifugation and chromatography as described in Patent Document 1.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-198854 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Here, regarding the two types of particles to be separated, sometimes they are indistinguishable in terms of surface chemical / physical properties or mass / volume (there is no difference in the degree to which separation is possible). In this case, it is impossible to properly separate the two types of particles using centrifugation or chromatography as described above. For example, when trying to separate nanodiamonds containing NV (Nitrogen-Vacancy) centers from nanodiamonds without NV centers, since the surface chemical / physical properties of these two types of nanodiamonds are indistinguishable, it is difficult to properly separate them using centrifugation or chromatography as described above.

[0008] One aspect of the present invention is made in view of the above-mentioned actual situation, and its purpose is to properly sort two kinds of particles whose surface chemical / physical properties are indistinguishable from each other.

[0009] Methods for solving problems

[0010] One aspect of the particle sorting mechanism of the present invention includes a flow path, a first light source assembly, and a second light source assembly. The flow path contains a plurality of first nanoparticles including absorbers having a given absorption energy level and a plurality of second nanoparticles not having absorbers having a given absorption energy level. The flow path has a first input section and a second input section. The first light source assembly outputs first light in a direction from the first input section toward the second input section, and the first light is absorbed by the absorbers having the given absorption energy level. The second light source assembly outputs second light in a direction from the second input section toward the first input section, and the second light is not absorbed by the absorbers having the given absorption energy level, but is scattered or absorbed by the second nanoparticles.

[0011] According to one aspect of the particle sorting mechanism of the present invention, for a plurality of first nanoparticles containing an absorber having a given absorption energy level, they are easily transported along a direction from the first input section toward the second input section by first light absorbed by the absorber. On the other hand, for a plurality of second nanoparticles not containing an absorber having a given absorption energy level, they are easily transported along a direction from the second input section toward the first input section by second light scattered or absorbed by the second nanoparticle. Thus, the positions of the first nanoparticles containing the absorber and the second nanoparticles not containing the absorber after transport are easily separated, and the first nanoparticles and the second nanoparticles can be appropriately sorted. Such a sorting method can also be implemented for two types of particles whose surface chemical / physical properties are indistinguishable from each other. Therefore, according to one aspect of the particle sorting mechanism of the present invention, two types of particles whose surface chemical / physical properties are indistinguishable from each other can be appropriately sorted.

[0012] The aforementioned particle sorting mechanism may further include a control unit that controls the light output of the first and second light source components. The control unit controls the first and second light source components by adjusting the intensity and frequency of the first and second light, so that the first nanoparticle is transported along the direction from the first input section to the second input section, and the second nanoparticle is transported along the direction from the second input section to the first input section. By adjusting the intensity and frequency of each light in this way, the first and second nanoparticles can be sorted more effectively.

[0013] The flow path may include: a first portion extending from a first input section to a first confluence point along a first direction; a second portion extending from the first confluence point to a second input section along a second direction intersecting the first direction; a third portion extending from the second input section to a second confluence point along a direction approaching the first input section in the first direction; a fourth portion extending from the second confluence point to a third confluence point contained in the first portion; a first reflector disposed at the first confluence point that reflects first light from the first portion toward the second portion and reflects second light from the second portion toward the first portion; a second reflector disposed at the second input section that reflects first light from the second portion toward the third portion; and a third reflector disposed at the second confluence point that reflects first light from the third portion toward the fourth portion.

[0014] In this structure, a ring structure is formed by a flow path extending from the third confluence point to the first confluence point, a flow path extending from the first confluence point to the second input section, a flow path extending from the second input section to the second confluence point, and a flow path extending from the second confluence point to the third confluence point. In the first and second sections, the first and second light rays pass in opposite directions, while in the third and fourth sections, only the first light rays pass through. Therefore, in the flow paths from the second input section through the second confluence point to the third confluence point, which are the third and fourth sections, only the first and second nanoparticles are transported by the first light rays. Furthermore, for the first and second nanoparticles that reach the third confluence point (the point included in the first section), the light pressure of the first and second light rays, which travel in opposite directions, acts upon them. Here, for the first nanoparticle, since it absorbs the first light through an absorber with a given absorption energy level but does not absorb the second light, the first light becomes dominant, and it is repeatedly transported through the aforementioned ring-structured flow path (the flow path from the third confluence point through the first confluence point, the second input section, and back to the third confluence point). On the other hand, for the second nanoparticle, since it does not contain the aforementioned absorber, it does not absorb the first light, and the first light is not dominant compared to the first nanoparticle. Therefore, there are two types of particles: those transported along the direction from the third confluence point toward the first input section and those transported within the ring-structured flow path. However, when the second nanoparticle transported within the ring-structured flow path reaches the third confluence point again, it is again divided into particles transported along the direction from the third confluence point toward the first input section and particles transported within the ring-structured flow path. Therefore, by repeating this process, after a sufficient amount of time, most of the second nanoparticles will be transported along the direction toward the first input section. In this way, long-term / long-distance transport can be achieved through the ring structure, thereby enabling repeated transport of the first nanoparticle within the flow path of the ring structure and transport of the second nanoparticle to the flow path outside the ring structure. Therefore, the areas where the first and second nanoparticles are present can be separated, allowing for appropriate sorting of the first and second nanoparticles. Furthermore, since the first nanoparticle is concentrated in the flow path (circulation section) of the ring structure, it can be easily recovered.

[0015] Alternatively, the first nanoparticle can be a nanodiamond containing an NV center that acts as an absorber, and the second nanoparticle can be a nanodiamond without an NV center that acts as an absorber. By using a particle sorting mechanism according to one aspect of the present invention to sort nanodiamonds containing NV centers and nanodiamonds without NV centers, it is possible to achieve proper sorting of nanodiamonds containing NV centers, which are of high value as components of quantum information technology and as highly sensitive sensing materials, including those for biological applications.

[0016] The effects of the invention

[0017] According to one aspect of the present invention, it is possible to appropriately sort two types of particles whose surface chemical / physical properties are indistinguishable from each other. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating a particle sorting mechanism according to an embodiment of the present invention.

[0019] Figure 2 Based on Figure 1 The diagram illustrates the particle sorting process of the particle sorting mechanism.

[0020] Figure 3 This diagram illustrates the adjustment of resonant and non-resonant light.

[0021] Figure 4 This is a diagram illustrating particle condensation based on a ring structure.

[0022] Figure 5 middle, Figure 5 (a) is a graph showing the time-varying number of resonant and non-resonant particles present closer to the direction of resonant light delivery than the initial position without a ring structure. Figure 5 (b) is a diagram showing the locations of resonant and non-resonant particles at 200,000 steps (equivalent to 2,000 [s]) without the ring structure.

[0023] Figure 6 middle, Figure 6 (a) is a graph showing the time variation of the number of resonant and non-resonant particles present on the side closer to the direction of resonant light transport than the initial position when the side length of the ring structure is d = 125 μm. Figure 6 (b) is a diagram showing the locations of resonant and non-resonant particles at 200,000 steps with a side length of d = 125 μm in the ring structure.

[0024] Figure 7 middle, Figure 7 (a) is a graph showing the time-varying number of resonant and non-resonant particles present closer to the direction of resonant light transport than the initial position when the side length of the ring structure is d = 62.5 μm. Figure 7 (b) is a diagram showing the locations of resonant and non-resonant particles at 200,000 steps with a side length of d = 62.5 μm in the ring structure.

[0025] Figure 8 middle, Figure 8(a) is a graph showing the time-varying number of resonant and non-resonant particles present on the side closer to the resonant light-based transport direction than the initial position when the side length of the ring structure is d = 25 μm. Figure 8 (b) is a diagram showing the locations of resonant and non-resonant particles at 200,000 steps with a side length d = 25 μm in the ring structure.

[0026] Figure 9 This diagram illustrates the usefulness of the particle sorting mechanism as a concentration mechanism.

[0027] Symbol Explanation

[0028] 1···Particle sorting mechanism, 2···Laser (first light source assembly), 3···Laser (second light source assembly), 4···Flow path, 10···Part 1, 20···Part 2, 30···Part 3, 40···Part 4, 51···First input section, 52···First confluence point, 53···Second input section, 54···Second confluence point, 55···Third confluence point, 61···Reflector (first reflector), 62···Half-reflector (second reflector), 63···Reflector (third reflector), 200···Control section, L1···Resonant light (first light), L2···Non-resonant light (second light), N1···Resonant particle (first nanoparticle), N2···Non-resonant particle (second nanoparticle). Detailed Implementation

[0029] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. In the description, the same symbol is used for the same element or elements having the same function, and repeated descriptions are omitted.

[0030] Figure 1 This diagram schematically illustrates the particle sorting mechanism 1 of this embodiment. The particle sorting mechanism 1 of this embodiment is a device that uses a microfluidic path and two types of lasers to sort two types of nanoparticles and concentrate / recover one type of nanoparticle. The two types of nanoparticles here are, for example, nanoparticles whose surface chemical and physical properties (mass, etc.) are common (without difference). In this embodiment, one type of nanoparticle is a first nanoparticle containing an absorber having a given absorption energy level, and the other type of nanoparticle is a second nanoparticle that does not contain the aforementioned absorber having a given absorption energy level. More specifically, the first nanoparticle in this embodiment is nanodiamond containing an NV center as an absorber having a given absorption energy level, and the second nanoparticle is nanodiamond that does not contain the aforementioned NV center as an absorber having a given absorption energy level.

[0031] Nanodiamonds containing NV centers are valuable as components of quantum information technology and as highly sensitive sensing materials, including for biological applications. However, they constitute a very small percentage of the total produced nanodiamonds, making it difficult to efficiently recover only those containing NV centers. Therefore, there is a need to sort, concentrate, and recover nanodiamonds containing NV centers from the produced nanodiamonds. Since nanodiamonds containing and without NV centers share similar surface chemical / physical properties, they are difficult to separate using conventional methods such as centrifugation and chromatography. Therefore, in the particle sorting mechanism 1 of this embodiment, a microfluidic path and two types of lasers are used to separately transport nanodiamonds containing NV centers (as first nanoparticles) and nanodiamonds without NV centers (as second nanoparticles) to different regions for sorting, and to concentrate / recover nanodiamonds containing NV centers. More specifically, by irradiating the first nanoparticles with light that resonates with their electronic transitions, the radiative power of the first nanoparticles is enhanced, thereby transporting the first nanoparticles to a different region than the second nanoparticles. In the following, nanodiamonds containing NV centers will sometimes be referred to as resonant particles, and nanodiamonds without NV centers will be referred to as non-resonant particles.

[0032] like Figure 1 As shown, the particle sorting mechanism 1 includes a recirculation device 100, a laser 2 (first light source assembly), a laser 3 (second light source assembly), and a control unit 200. The recirculation device 100 includes a flow path 4, a reflector 61 (first reflector), a half-reflector 62 (second reflector), and a reflector 63 (third reflector).

[0033] Flow path 4 is a flow path containing multiple resonant particles (e.g., nanodiamonds containing NV centers) and multiple non-resonant particles (e.g., nanodiamonds without NV centers), and having a first input section 51 and a second input section 53. The first input section 51 is the input section for light irradiated by the laser 2 (details will be described later). The second input section 53 is the input section for light irradiated by the laser 3 (details will be described later). Flow path 4 has a first section 10, a second section 20, a third section 30, and a fourth section 40.

[0034] Part 10 is along the first direction ( Figure 1 The second part 20 extends from the first input section 51 to the first confluence point 52 in the direction extending from left to right in the first direction. Figure 1 The third part 30 extends from the first confluence point 52 to the second input section 53 in the direction extending upwards from the bottom. Figure 1The portion extending from the second input section 53 to the second confluence point 54 (in the direction extending from right to left) is called the fourth portion 40. The portion extending from the second confluence point 54 to the third confluence point 55 included in the first portion 10 is called the fourth portion 40. In this way, a loop structure is formed in the flow path 4, which runs from the third confluence point 55 through the first confluence point 52, the second input section 53, and the second confluence point 54 and returns to the third confluence point 55. Each side of the loop structure can be, for example, about a few μm to several hundred μm. Each side of the loop structure refers to the portion from the third confluence point 55 to the first confluence point 52 in the first portion 10, the second portion 20, the third portion 30, and the fourth portion 40. All sides of the loop structure can be of the same length, or only the sides opposite each other can be of the same length, or they can be of different lengths.

[0035] A reflector 61, located at the first confluence point 52, reflects the first light (resonant light from laser 2, described later) from the first part 10 toward the second part 20 and reflects the second light (non-resonant light from laser 3, described later) from the second part 20 toward the first part 10. A half-reflector 62, located at the second input section 53, reflects the first light (resonant light from laser 2, described later) from the second part 20 toward the third part 30. The half-reflector 62 transmits the non-resonant light from laser 3 toward the second part 20. A reflector 63, located at the second confluence point 54, reflects the first light (resonant light from laser 2, described later) from the third part 30 toward the fourth part 40.

[0036] Laser 2 outputs resonant light (first light) that can be absorbed by the NV center, which is an absorber having a given absorption energy level, along the direction from the first input section 51 toward the second input section 53 (more specifically, from the first input section 51 toward the first confluence point 52). Laser 3 outputs non-resonant light (second light) that is not absorbed by the NV center and can be scattered or absorbed at least by non-resonant particles, which are second nanoparticles without NV centers, along the direction from the second input section 53 toward the first input section 51 (more specifically, from the second input section 53 toward the first confluence point 52).

[0037] Figure 2 Based on Figure 1 The diagram illustrates the particle sorting process of particle sorting mechanism 1. (See diagram for example.) Figure 2As shown, the resonant light L1 output from laser 2 is input from the first input section 51, passes through the first part 10, is reflected by mirror 61 and passes through the second part 20, is further reflected by half-reflector 62 and passes through the third part 30, is then reflected by mirror 63 and passes through the fourth part 40, reaching the third confluence point 55. Meanwhile, the non-resonant light L2 output from laser 3 is input from the second input section 53, passes through the second part 20, is reflected by mirror 61 and passes through the first part 10, reaching the first input section 51.

[0038] Resonant light L1 is light that can be absorbed by the NV center of resonant particle N1. Therefore, resonant particle N1 is easily transported along the direction of resonant light L1. Conversely, non-resonant light L2 is light that is scattered or absorbed by non-resonant particles. Therefore, non-resonant particle N2 is easily transported along the direction of non-resonant light L2. Furthermore, since resonant light L1 and non-resonant light L2 pass in opposite directions in parts 10 and 20, the different directions of resonant light L1 and non-resonant light L2 can be used to transport and sort resonant particles N1 and non-resonant particles N2 along different directions.

[0039] Here, for resonant particles N1, not only resonant light L1 but also non-resonant light L2 is irradiated. Non-resonant light L2 can scatter from resonant particles N1, and this scattering can transport resonant particles N1 along the direction of non-resonant light L2. Conversely, for non-resonant particles N2, not only non-resonant light L2 but also resonant light L1 is irradiated. Although resonant light L1 is not absorbed by non-resonant particles N2, it can scatter from them, and this scattering can transport non-resonant particles N2 along the direction of resonant light L1. That is, for example, in Part 10, since resonant particles N1 are irradiated with non-resonant light L2 in the opposite direction in addition to the resonant light L1 related to absorption, and non-resonant particles N2 are irradiated with resonant light L1 in the opposite direction in addition to non-resonant light L2, there is a risk that the desired transport and sorting cannot be achieved without any control over resonant light L1 and non-resonant light L2. Furthermore, when transporting particles via resonant light L1 and non-resonant light L2, the distance transported by these lights needs to be sufficiently large relative to the distance traveled based on Brownian motion (dispersion) as the random motion (dispersion) of the particles. That is, the resonant light L1 and non-resonant light L2 need to be controlled so that particle transport can be distinguished from movement caused by Brownian motion. The control unit 200 is configured to perform such control of the resonant light L1 and non-resonant light L2.

[0040] The control unit 200 controls the light output of laser 2 and laser 3. The control unit 200 controls laser 2 and laser 3 in a manner that adjusts the intensity and frequency of resonant light L1 and non-resonant light L2, so that resonant particles N1 are transported in the direction from the first input unit 51 to the second input unit 53, and non-resonant particles N2 are transported in the direction from the second input unit 53 to the first input unit 51.

[0041] The control unit 200 controls lasers 2 and 3 by adjusting the intensity and frequency of the resonant light L1 and the non-resonant light L2, such that the particle transport distance caused by the resonant light L1 and the non-resonant light L2 is sufficiently greater than the particle dispersion distance caused by Brownian motion. The particle transport distance X caused by light... h It is expressed by the following equation (1). Additionally, the dispersion distance X caused by Brownian motion... d It is expressed by the following equation (2). In the following equations (1) and (2), η is the viscosity coefficient, and k B Boltzmann constant (1.38 × 10⁻⁶) -23 (where r is particle size, T is temperature, F is the radiative force exerted on the particle by light, and t is time. As an example, the viscosity coefficient η is 0.89 × 10⁻⁶.) -3 [Pa·s], particle size r is 20.0 [nm], temperature T is 300 [K].

[0042] [Mathematical Expression 1]

[0043]

[0044] [Mathematical Expression 2]

[0045]

[0046] Used to make the conveying distance X h Sufficiently greater than the dispersion distance X d The conditional expression is represented by, for example, the following expression (3).

[0047] [Mathematical Expression 3]

[0048]

[0049] The control unit 200 adjusts the intensity and frequency of the resonant light L1 and the non-resonant light L2 in such a way that the radiation force F of the resonant particle N1 and the non-resonant particle N2 can be set separately, so as to satisfy the above equation (3).

[0050] Furthermore, the control unit 200 controls the laser 2 and laser 3 by adjusting the intensity and frequency of the resonant light L1 and the non-resonant light L2, so that the resonant particle N1 is transported along the direction of the resonant light L1, and the non-resonant particle N2 is transported along the direction of the non-resonant light L2. For the control unit 200, firstly, as... Figure 3 For example, the energy of the resonant light L1 is adjusted to 2.33 eV and the frequency is adjusted to 5.63 × 10⁻⁶. 14 Hz, intensity adjusted to 2.5MW / cm 2 This allows the resonant particles N1 to be transported along the direction of the resonant light L1 (even considering Brownian motion). In this case, for example, in a resonant particle N1 comprising 10 NV centers Ab as absorbers, the radiative force relative to the absorption by the NV centers Ab (e.g., F = 6.2 × 10⁻⁶) is... -2 [fN]), the radiative force generated by scattering from the parent body of the resonant particle N1 (e.g., F = 6.4 × 10⁻⁶). -1 [fN]) increases. The control unit 200 sets the radiation force generated by the scattering of the non-resonant light L2, which travels in the opposite direction to the resonant light L1, so that the radiation force generated by the scattering of the resonant light L1 relative to the parent particle is eliminated in the resonant particle N1. Therefore, for the resonant particle N1, the radiation force generated by the absorption of the NV center Ab becomes dominant and is transported along the direction of the resonant light L1. Furthermore, for the control unit 200, as... Figure 3 For example, the energy of the non-resonant light L2 is adjusted to 1.16 eV and the frequency is adjusted to 2.81 × 10⁻⁶ eV. 14 Hz, intensity adjusted to 41MW / cm 2 This eliminates the radiation force generated by the scattering of resonant light L1 relative to the parent body of resonant particle N1, and allows non-resonant particle N2 to be transported along the direction of non-resonant light L2, even considering the effects of Brownian motion and resonant light L1. As described above, the control unit 200 adjusts the intensity and frequency of the resonant light L1 and non-resonant light L2, which are irradiated in opposite directions, based on Brownian motion, to transport resonant particle N1 along the direction of resonant light L1 and non-resonant particle N2 along the direction of non-resonant light L2. It should be noted that the conditions for resonant light L1 and non-resonant light L2 described above are just one example. Regarding the resonant frequency, restrictions are imposed on each target particle, while the combination of intensity and wavelength can be freely selected.

[0051] Here, as described above, the radiation force generated by absorption at the NV center in the resonant particle N1 is very small compared to the radiation force caused by scattering from the parent body of the resonant particle N1. To transport the resonant particle N1 along the direction of the resonant light L1 with such a small radiation force, a long-term / long-distance transport is required. That is, a long flow path is needed to obtain the difference in the movement distance (the difference in movement distance between resonant particle N1 and non-resonant particle N2) by irradiating the particles that disperse over time. Furthermore, to separately recover the sorted resonant particles N1 and non-resonant particles N2, their respective areas of presence need to be clearly separated. To meet this requirement, as described above, by employing a reflux device 100 with a ring structure, long-term repeated transport can be performed using the ring structure, and the resonant particles N1 can be concentrated and recovered within the ring structure. Moreover, even with a small radiation force, the sorting and recovery of the resonant particles N1 can be achieved.

[0052] Now, Figure 2 The third confluence point 55 shown is set as the initial position of each particle. For each resonant particle N1, it is transported along the direction of the resonant light L1 by the radiation force generated by the absorption of the resonant light L1 at the center of NV. Therefore, each resonant particle N1 is transported in a manner that uses the third confluence point 55 as the initial position and repeats the cycle in the ring structure. On the other hand, for each non-resonant particle N2, it is affected by the diffusion (diffusion or absorption for the non-resonant light L2) of the resonant light L1 and the non-resonant light L2, which are traveling in opposite directions to each other, for example, along the direction of the resonant light L1 or the direction of the non-resonant light L2 (from... Figure 2 The third confluence point 55 disperses and is transported to the left and right directions.

[0053] Figure 4 This is a diagram illustrating particle concentration based on a ring structure. Now, for non-resonant particles N2, suppose they are dispersed at a constant rate along the left and right directions starting from the third confluence point 55, which is the initial position. In this case, as... Figure 4 As shown in (a), when multiple resonant particles N1 and multiple non-resonant particles N2 are released to the third confluence point 55, which serves as the initial position, as Figure 4 As shown in (b), each resonant particle N1 is transported into the ring structure via the resonant light L1. On the other hand, as... Figure 4 As shown in (b), for each non-resonant particle N2, it is dispersed and transported to half inside and half outside the ring structure. Furthermore, as... Figure 4As shown in (c), only the resonant particles N1 and non-resonant particles N2 within the ring structure circulate within the ring structure and return to the third confluence point. Each resonant particle N1 is transported into the ring structure, while each non-resonant particle N2 is dispersed and transported in equal numbers, one inside and one outside the ring structure. By repeating this circulation within the ring structure, the number of resonant particles N1 remains constant, circulating entirely within the ring structure. Conversely, the number of non-resonant particles N2 circulating within the ring structure gradually decreases with each circulation. Therefore, by ensuring sufficient time for particle circulation, the locations where resonant particles N1 and non-resonant particles N2 exist can be divided into inside and outside the ring structure, allowing for easy recovery of the resonant particles N1 within the ring structure.

[0054] Next, refer to Figures 5-8 The effect of particle concentration based on ring structures is explained. Figures 5-8 The results corresponding to the passage of time are shown for cases where 10,000 resonant particles N1 and 10,000 non-resonant particles are transported from the initial position. Figures 5-8 In the diagram, (a) shows the time variation in the number of resonant particles N1 and non-resonant particles N2 located closer to the direction of transmission based on resonant light L1 than the initial position, and (b) shows the positions of resonant particles N1 and non-resonant particles N2 after 200,000 steps (2000 [s]). In (a), the horizontal axis represents the step, and the vertical axis represents the number of particles. In (b), the horizontal axis represents the position to the left or right of setting the initial position to 0 (distance normalized to 0.5 μm), and the vertical axis represents the number of particles. The "+" side of the horizontal axis in (b) is the direction of transmission based on resonant light L1. It should be noted that non-resonant particles N2 are considered to be dispersed at a uniform rate to the left and right from the initial position.

[0055] Figure 5 The results are shown for the case without a ring structure. For example... Figure 5 As shown in (a), without the ring structure, for resonant particles N1, the number transported towards the direction of transport based on resonant light L1 increases accordingly with the passage of time, but for non-resonant particles N2, they are dispersed at a constant rate along the left and right directions, and even as time passes, the increase or decrease in the number transported towards the direction of transport based on resonant light L1 is small. Figure 5 As shown in (b), after 200,000 steps (2000 [S]) and a sufficient amount of time, the non-resonant particles N2 disperse at an equal rate to the left and right, while the positions of the resonant particles N1 and the non-resonant particles N2 tend to overlap. In this case, it is impossible to properly sort the resonant particles N1 and the non-resonant particles N2 separately, and it is difficult to easily recover the resonant particles N1.

[0056] Figure 6The results are shown for the case where a ring structure exists and the side length of the ring structure is d = 125 μm. It should be noted that the presence of a ring structure refers to the configuration of the reflux device 100 of the particle sorting mechanism 1 described above (the same applies below). Figure 6 As shown in (a), due to the presence of the ring structure, the non-resonant particles N2 are gradually discharged from the ring structure each time they circulate within it. Therefore, over time, the number of non-resonant particles N2 present on the side based on the transport direction of the resonant light L1 (i.e., the ring structure side) continuously decreases. Thus, as... Figure 6 As shown in (b), after 200,000 steps (2000 [S]) and a sufficient amount of time, a large number of non-resonant particles N2 exist on the outer side of the ring structure. Figure 6 (b) On the horizontal axis "-" side), the positions of resonant particle N1 and non-resonant particle N2 are unlikely to overlap. Therefore, with Figure 5 Compared to the previous example, the ability to properly sort resonant particles N1 and non-resonant particles N2 separately allows for the easy recovery of resonant particles N1.

[0057] Figure 7 The results are shown for the case where a ring structure exists with a side length d = 62.5 μm. By shortening the side length d, the particle circulation period is accelerated, increasing the chance that non-resonant particles N2 will be expelled from the third confluence point 55, which serves as the initial position, outside the ring structure. Therefore, as... Figure 7 As shown in (a), the side length of the ring structure is d = 125 μm. Figure 6 Compared to the previous example, the decrease in the number of non-resonant particles N2 present on one side of the ring structure increases accordingly with the passage of time. Therefore, as... Figure 7 As shown in (b), after 200,000 steps (2000 [S]) and a sufficient amount of time, a large number of non-resonant particles N2 exist on the outer side of the ring structure. Figure 7 (b) On the horizontal axis "-" side), the positions of resonant particle N1 and non-resonant particle N2 are less likely to overlap. Therefore, with Figure 6 Compared to the previous example, the ability to sort resonant particles N1 and non-resonant particles N2 more appropriately makes it easier to recover resonant particles N1.

[0058] Figure 8 The results are shown for the case where a ring structure exists and the side length of the ring structure is d = 25 μm. For example... Figure 8 As shown in (a), due to the further shortening of the side length d, the side length of the ring structure is d = 62.5 μm. Figure 7Compared to the previous example, the reduction in the amount of non-resonant particles N2 present on one side of the ring structure increases further with the passage of time. After 200,000 steps (2000 [S]), the concentration of non-resonant particles N2 in the ring structure decreases to about 1 / 10 of the total amount of non-resonant particles N2. Therefore, as Figure 8 As shown in (b), after 200,000 steps (2000 [S]) and a sufficient amount of time, a large number of non-resonant particles N2 exist on the outer side of the ring structure. Figure 8 (b) On the horizontal axis "-" side), the positions of resonant particle N1 and non-resonant particle N2 are less likely to overlap. Therefore, with Figure 7 Compared to the previous example, the ability to sort resonant particles N1 and non-resonant particles N2 more appropriately makes it easier to recover resonant particles N1.

[0059] Figure 9 This diagram illustrates the usefulness of particle sorting mechanism 1 as a concentration mechanism. Figure 9 In the diagram, the horizontal axis represents time, and the vertical axis represents the number of particles in the ring structure of flow path 4. Now, suppose that in the particle sorting mechanism 1 with the ring structure, 10 resonant particles N1 and 100,000 non-resonant particles N2 are released at the third confluence point 55, which is the initial position, resonant light L1 is irradiated from laser 2, and non-resonant light L2 is irradiated from laser 3. In this case, as... Figure 9 As shown, after 20,000 [s], for resonant particles N1, 10 remain unchanged from the initial state and are present in the ring structure, while for non-resonant particles N2, only 2,872 are present in the ring structure. Before implementing this ring structure-based sorting, the proportion of resonant particles N1 in the total particles was 10 / 1000 × 0.01%, while after implementing the ring structure-based sorting (e.g., after 200,000 [s]), the proportion of resonant particles N1 in the ring structure increased to 10 / 2837 × 0.35%. In this way, by using the particle sorting mechanism 1 with the ring structure for about 5 hours of particle circulation, the concentration of resonant particles N1 in the ring structure can be increased by about 35 times.

[0060] Next, the effects of the particle sorting mechanism 1 in this embodiment will be explained.

[0061] The particle sorting mechanism 1 of this embodiment includes: a flow path 4, wherein there are a plurality of first nanoparticles containing absorbers having a given absorption energy level and a plurality of second nanoparticles not containing absorbers having a given absorption energy level, and has a first input section 51 and a second input section 53; a laser 2, which outputs first light in a direction from the first input section 51 toward the second input section 53, the first light being absorbed by absorbers having a given absorption energy level; and a laser 3, which outputs second light in a direction from the second input section 53 toward the first input section 51, the second light not being absorbed by absorbers having a given absorption energy level and being scattered or absorbed by the second nanoparticles.

[0062] According to the particle sorting mechanism 1 of this embodiment, multiple first nanoparticles containing absorbers having a given absorption energy level are easily transported along the direction from the first input section 51 to the second input section 53 by first light absorbed by the absorber. On the other hand, multiple second nanoparticles not containing absorbers having a given absorption energy level are easily transported along the direction from the second input section 53 to the first input section 51 by second light scattered or absorbed by the second nanoparticles. Thus, the positions of the first nanoparticles containing absorbers and the second nanoparticles not containing absorbers after transport can be easily separated, and the first nanoparticles and second nanoparticles can be appropriately sorted. Such a sorting method can also be implemented for two types of particles whose surface chemical / physical properties are indistinguishable from each other. Therefore, the particle sorting mechanism 1 of this embodiment can appropriately sort two types of particles whose surface chemical / physical properties are indistinguishable from each other.

[0063] The particle sorting mechanism 1 described above may further include a control unit 200 for controlling the light output of lasers 2 and 3. The control unit 200 controls lasers 2 and 3 in a manner that adjusts the intensity and frequency of the first and second light, so that the first nanoparticle is transported along the direction from the first input section 51 towards the second input section 53, and the second nanoparticle is transported along the direction from the second input section 53 towards the first input section 51. By adjusting the intensity and frequency of each light in this way, the first and second nanoparticles can be sorted more effectively.

[0064] The flow path 4 may have: a first portion 10 extending from the first input section 51 to the first confluence point 52 along a first direction; a second portion 20 extending from the first confluence point 52 to the second input section 53 along a second direction intersecting the first direction; a third portion 30 extending from the second input section 53 to the second confluence point 54 along a direction approaching the first input section 51 in the first direction; and a fourth portion 20 extending from the second confluence point 54 to the third confluence point 55 included in the first portion 10. The system comprises: a portion 40; a reflector 61 disposed at the first confluence point 52, which reflects the first light from the first portion 10 toward the second portion 20 and the second light from the second portion 20 toward the first portion 10; a semi-reflector 62 disposed at the second input portion 53, which reflects the first light from the second portion 20 toward the third portion 30; and a reflector 63 disposed at the second confluence point 54, which reflects the first light from the third portion 30 toward the fourth portion 40.

[0065] In this structure, a ring structure is formed by a flow path extending from the third confluence point 55 to the first confluence point 52 (first part 10), a flow path extending from the first confluence point 52 to the second input section 53 (second part 20), a flow path extending from the second input section 53 to the second confluence point 54 (third part 30), and a flow path extending from the second confluence point 54 to the third confluence point 55 (fourth part 40). In the first part 10 and the second part 20, the first and second light rays pass in opposite directions, while in the third part 30 and the fourth part 40, only the first light rays pass through. Therefore, in the flow paths of the third part 30 and the fourth part 40, from the second input section 53 through the second confluence point 54 to the third confluence point 55, only the first light rays are used to transport the first and second nanoparticles. Furthermore, for the first nanoparticle and the second nanoparticle that reach the third confluence point 55 (the point included in part 10), the light pressure of the first light and the second light traveling in opposite directions will act. Here, for the first nanoparticle, since it absorbs the first light through an absorber with a given absorption energy level and does not absorb the second light, the first light becomes dominant, and it is repeatedly transported through the above-mentioned flow path of the ring structure (the flow path from the third confluence point 55 through the first confluence point 52, the second input section 53, and the second confluence point 54 and back to the third confluence point 55). On the other hand, for the second nanoparticle, since it does not contain the above-mentioned absorber, it does not absorb the first light, and compared with the first nanoparticle, the first light does not become dominant. Therefore, there are both particles transported along the direction from the third confluence point 55 toward the first input section 51 and particles transported within the flow path of the ring structure. However, when the second nanoparticles transported within the flow path of the ring structure reach the third confluence point 55 again, they are again separated into particles transported along the direction from the third confluence point 55 towards the first input section 51 and particles transported within the flow path of the ring structure. Therefore, by repeating this process, after a sufficient period of time, most of the second nanoparticles will be transported along the direction towards the first input section. That is, non-resonant particles can be effectively excluded from the ring structure. In this way, by utilizing the ring structure to achieve long-term / long-distance transport, the first nanoparticles can be repeatedly transported within the flow path of the ring structure, and the second nanoparticles can be transported to the flow path outside the ring structure. Therefore, the areas where the first and second nanoparticles are present can be separated, thereby appropriately sorting the first and second nanoparticles. In addition, since the first nanoparticles are concentrated in the flow path (circulation section) of the ring structure, the first nanoparticles can be easily recovered.

[0066] Alternatively, the first nanoparticle can be a nanodiamond containing an NV center that serves as an absorber, and the second nanoparticle can be a nanodiamond without an NV center that serves as an absorber. By using the particle sorting mechanism 1 of this embodiment to sort nanodiamonds containing NV centers and nanodiamonds without NV centers, it is possible to appropriately recover high-value nanodiamonds containing NV centers that are components of quantum information technology and highly sensitive sensing materials, including those used in biological applications.

[0067] The above description describes this embodiment, but the present invention is not limited to the above embodiment. For example, the first nanoparticle was described as "nanodiamond containing NV centers" and the second nanoparticle as "nanodiamond without NV centers," but it is not limited to this. For example, the first nanoparticle and the second nanoparticle may also be quantum dots of different sizes. In this case, the intensity of the resonant light may be set to, for example, 1 kW / cm². 2 The frequency can be set to a value dependent on the corresponding quantum dot. Additionally, the first and second nanoparticles can also be carbon nanotubes. In this case, the intensity of the resonant light can be set, for example, to 1 MWcm. 2 The frequency can be set to approximately 2.4 × 10⁻⁶. 14 Hz.

Claims

1. A particle sorting mechanism, comprising a flow path, a first light source assembly, and a second light source assembly. The flow path contains multiple first nanoparticles that include absorbers with a given absorption energy level and multiple second nanoparticles that do not contain absorbers with the given absorption energy level, and the flow path has a first input section and a second input section. The first light source assembly outputs first light in a direction from the first input portion toward the second input portion, and the first light is absorbed by the absorber having a given absorption energy level. The second light source assembly outputs a second light in a direction from the second input portion toward the first input portion. This second light is not absorbed by the absorber having a given absorption energy level, and is either scattered or absorbed by the second nanoparticles. The particle sorting mechanism further includes a control unit for controlling the light output of the first light source assembly and the second light source assembly. The control unit controls the first light source assembly and the second light source assembly by adjusting the intensity and frequency of the first light and the second light, so that the first nanoparticle is transported in the direction from the first input unit toward the second input unit, and the second nanoparticle is transported in the direction from the second input unit toward the first input unit.

2. The particle sorting mechanism of claim 1, wherein, The flow path has: The first portion extending along the first direction from the first input section to the first confluence point; The second part extends from the first confluence point to the second input section along a second direction that intersects the first direction; The third part extends from the second input section to the second confluence point in a direction that approaches the first input section along the first direction; The fourth part extends from the second confluence point to the third confluence point contained in the first part; A first reflecting mirror is disposed at the first confluence point, which reflects the first light from the first part toward the second part and reflects the second light from the second part toward the first part; A second reflecting mirror disposed at the second input section, reflecting the first light from the second part toward the third part; and A third reflecting mirror, located at the second confluence point, reflects the first light from the third part toward the fourth part.

3. The particle sorting mechanism according to claim 1 or 2, wherein, The first nanoparticle is a nanodiamond containing an NV center that serves as the absorber. The second nanoparticle is a nanodiamond that does not contain the NV center that serves as the absorber.

4. The particle sorting mechanism according to claim 1 or 2, wherein, The first nanoparticle and the second nanoparticle are nanoparticles whose surface chemical and physical properties are common to each other.

5. The particle sorting mechanism according to claim 2, wherein, The portion from the third confluence point to the first confluence point in the first part, the second part, the third part, and the fourth part are the sides that constitute the ring structure.

6. The particle sorting mechanism according to claim 5, wherein, The sides that make up the ring structure are all of the same length.

7. The particle sorting mechanism according to claim 5, wherein, In the ring structure, only the sides that are opposite each other have the same length.

8. The particle sorting mechanism according to claim 1, wherein, The control unit controls the first light source assembly and the second light source assembly such that the distance transmitted to the first nanoparticle and the second nanoparticle by the first light and the second light is greater than the distance traveled by the first nanoparticle and the second nanoparticle based on Brownian motion as random motion.

9. The particle sorting mechanism according to claim 8, wherein, The distance that light can transport particles is expressed by the following equation (1). ， The distance a particle travels based on Brownian motion is expressed by the following equation (2). ， In the above formula (1) and formula (2), η is a viscosity coefficient, k B is a Boltzmann constant (1.38 x 10 -23 -23 J / K), r is a particle diameter, T is a temperature, F is a radiation force applied to a particle by light, and t is a time, for making X h greater than X d The conditional expression when expressed in the following formula (3) ， The control unit controls the first light source assembly and the second light source assembly by adjusting the intensity and frequency of the first light and the second light, so that the radiative power of the first nanoparticle and the second nanoparticle respectively satisfies the equation (3).

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