CN112014272B - Nanoparticle sensor and nanoparticle detection method - Google Patents
Nanoparticle sensor and nanoparticle detection method Download PDFInfo
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- CN112014272B CN112014272B CN202010796285.XA CN202010796285A CN112014272B CN 112014272 B CN112014272 B CN 112014272B CN 202010796285 A CN202010796285 A CN 202010796285A CN 112014272 B CN112014272 B CN 112014272B
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
- G01N2015/0038—Investigating nanoparticles
Abstract
The embodiment of the invention provides a nano particle sensor and a nano particle detection method, wherein the nano particle sensor comprises a silicon-based vertical heterodyne waveguide structure; the silicon-based vertical heterodyne waveguide structure comprises a probe waveguide and a signal waveguide which are vertically heterodyne, and a sensing area is formed at the junction of the probe waveguide and the signal waveguide; inputting local oscillation light as a local oscillation signal of the sensing area in the signal waveguide; in the probe waveguide, inputting probe light for interacting with the nano-particles to be detected in the sensing area; the probe light and the local oscillator light are coupled in the sensing area; when the nano particles to be detected enter the sensing area, the signal waveguide collects probe light scattered after the interaction between the nano particles to be detected and the probe light, and outputs beat frequency signals generated by coupling the local oscillator light and the scattered probe light. The nanoparticle sensor can realize rapid and stable nanoparticle detection.
Description
Technical Field
The invention relates to the technical field of photonic integrated sensing, in particular to a nanoparticle sensor and a nanoparticle detection method.
Background
Although not directly observable by the naked eye in life, nanoparticles are closely related to the content of human productive activities. Dust particles in common air such as PM2.5, PM1.0 and the like have great influence on the health of human respiratory systems, and the index of rapid and timely monitoring has great reference value for reflecting the environmental quality. In pneumonia caused by coronavirus, which has been developed in the past, the virus radius is on the order of tens of nanometers, and the virus is very easy to transmit through air. Influenza outbreaks occur every year around the world, with viral radii of tens of nanometers as well. Nowadays, the existence of nano particles and viruses greatly influences the physical health of people, and how to realize the rapid and high-sensitivity detection of the nano particles is the important factor in environmental management and epidemic situation monitoring.
At present, there are two main approaches for high-sensitivity nanoparticle sensing using optical evanescent field sensors: resonant cavity and waveguide. The resonant cavity type optical sensor mainly depends on an optical sensing structure with high quality factor and low mode volume, and realizes the detection of nano particles by enhancing the interaction of optical domain substances. For example, a whispering gallery sphere cavity excites a whispering gallery mode in a microcavity in a coupling mode of a prism, an optical fiber and the like, when particles appear in an evanescent field of a resonance mode, the phenomena of mode movement, mode splitting, mode broadening and the like of a transmission line of the resonance cavity are caused due to the scattering of the particles, and the extraction of nano particle signals can be realized by detecting the peak value changes.
The field enhancement-based method is widely analyzed and optimized in research, although the sensing precision is very high and can reach the order of single molecule (radius less than 10 nanometers), the high-quality microcavity is difficult to prepare on a large scale, the microcavity cannot be compatible with the Complementary Metal Oxide Semiconductor (CMOS) processing technology, the measurement of the microcavity is very sensitive to the surrounding environment, and the measurement is difficult to measure in an actual scene after leaving the environment of a laboratory. The existing waveguide type nano particle sensor mainly adopts a nano optical fiber structure, and the range of an evanescent field is enlarged by reducing the diameter of a fiber core of the optical fiber, so that the interaction between nano particles and an optical field is enhanced. The sensor based on the nano optical fiber has poor manufacturing repeatability, the current technical means can only be used for drawing by manpower, the yield is limited, and the optical fiber structure needs a fixing device, is very fragile and is not used for practical use. Although the silicon waveguide-based nanoparticle sensor has the advantages of high repeatability and high stability, the sensitivity of the silicon waveguide-based nanoparticle sensor is limited to be about 100 nanometers by monitoring the intensity change of a transmission spectrum, and the sizes of viruses, molecules and the like are mostly dozens of nanometers, so that the use scene of the silicon waveguide-based nanoparticle sensor is limited. Therefore, the existing scheme is difficult to simultaneously meet the requirements of high precision, large-scale production and high stability of nanoparticle measurement.
Disclosure of Invention
The invention aims to provide a nano particle sensor and a nano particle detection method, which can realize rapid and stable nano particle detection.
In a first aspect, an embodiment of the present invention provides a nanoparticle sensor, including:
a silicon-based vertical heterodyne waveguide structure;
the silicon-based vertical heterodyne waveguide structure comprises a probe waveguide and a signal waveguide which are vertically arranged, and a sensing area is formed at the intersection of the probe waveguide and the signal waveguide; inputting local oscillation light as a local oscillation signal of the sensing area in the signal waveguide; in the probe waveguide, inputting probe light for interacting with the nano-particles to be detected in the sensing area; the probe light and the local oscillator light are coupled in the sensing area;
when the nano particles to be detected enter the sensing area, the signal waveguide collects probe light scattered after the interaction between the nano particles to be detected and the probe light, and outputs beat frequency signals generated by coupling the local oscillator light and the scattered probe light.
Optionally, the nanoparticle sensor further comprises:
and the signal processing unit is used for detecting the beat frequency signal and outputting a detection result.
Optionally, the signal processing unit is specifically configured to detect a strength change of the beat signal, scale information, and category information, and output a detection result.
Optionally, the nanoparticle sensor further includes a balance detector, a high-pass filter, and a radio frequency amplifier, before the signal processing unit detects the beat frequency signal, the balance detector and the radio frequency amplifier sequentially amplify the beat frequency signal, the balance detector further suppresses common mode noise, and the high-pass filters disposed at front and rear positions of the radio frequency amplifier are configured to filter low-frequency noise.
Optionally, the signal processing unit is specifically configured to obtain a positive correlation between the variation in the beat frequency signal and the radius of the nanoparticle to be detected, and determine the scale information of the nanoparticle to be detected based on the step variation determined by the positive correlation.
Optionally, the nanoparticle sensor is provided with a dilution and atomization unit, and the dilution and atomization unit is used for performing dilution and atomization treatment on the nanoparticles to be detected before the nanoparticles to be detected enter the sensing area.
Optionally, the sensor is an integrated sensor fabricated based on standard Complementary Metal Oxide Semiconductor (CMOS) processing.
In a second aspect, an embodiment of the present invention provides a nanoparticle detection method, including:
detecting whether the nano particles enter a sensing area of a sensor, wherein the sensor comprises a silicon-based vertical heterodyne waveguide structure, the silicon-based vertical heterodyne waveguide structure comprises a probe waveguide and a signal waveguide which are vertically arranged, and a sensing area is formed at the intersection of the probe waveguide and the signal waveguide; inputting local oscillation light as a local oscillation signal of the sensing area in the signal waveguide; in the probe waveguide, inputting probe light for interacting with the nano-particles to be detected in the sensing area; the probe light and the local oscillator light are coupled in the sensing area;
if the nano particles are detected to enter the sensing area, collecting probe light scattered after the nano particles and the probe light interact;
outputting the beat frequency signal generated by coupling the local oscillation light and the scattered probe light;
and detecting the beat frequency signal and outputting a detection result.
Optionally, the detecting the beat frequency signal and outputting a detection result includes:
and detecting the strength change, the scale information and the type information of the beat frequency signal, and outputting a detection result.
Optionally, the detecting whether the nanoparticle enters the sensing region of the sensor previously comprises:
and carrying out dilution and atomization treatment on the nano particles.
According to the nanoparticle sensor and the nanoparticle detection method provided by the embodiment of the invention, the sensor based on the silicon-based vertical heterodyne waveguide structure generates the beat frequency signal, and the signal containing the information of the nanoparticles to be detected directly reflects in the change of the amplitude value of the beat frequency signal, so that the rapid and stable nanoparticle detection is realized based on the beat frequency signal.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a nanoparticle sensor according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an optical path structure of a nanoparticle sensor according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a beat signal extraction system matched with a heterodyne waveguide sensor according to an embodiment of the present invention;
FIG. 4 is a graph illustrating the results of a comparative experiment on a particle signal source according to an embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating the variation of signal intensity caused by standard particles with different radii according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of a calculation result of finite element simulation analysis performed on a light field in a sensing region of a sensor according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of improving detection efficiency based on a probe light field expansion scheme according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a sensor and microfluidic based combination according to an embodiment of the present invention;
fig. 9 is a flowchart of a nanoparticle detection method according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Silicon-based photonic technology has become one of the hot techniques of on-chip integrated sensing research in recent years, and a sensor based on a silicon-based orthogonal waveguide structure (silicon-based vertical heterodyne waveguide structure) realizes on-chip sensing with high signal-to-noise ratio and high sensitivity by amplifying weak signals and suppressing system noise. The method is different from the idea of enhancing the interaction of light and substances by a sensor based on a resonant cavity, and has important research breakthrough value and huge practical application prospect in the field of sensing. The nanoparticle waveguide heterodyne sensor is based on the principle of on-chip dark field interference, when a detected nanoparticle generates dipole radiation under the excitation of probe light, the radiation field of the probe light and a local oscillation field interfere in a signal waveguide, and the generated interference light field can be expressed as:
wherein E isbeatRepresenting beat light (beat signal) formed by the interference of probe light and local oscillator light in the signal waveguide, Eprobe、ωprobe、φprobe，Elocal、ωlocalAnd philocalCorresponding to the electric field amplitude E, angular frequency omega and optical phase phi, eta of the probe light and the local oscillator light respectivelysScattering light induced for nanoparticlesCollection efficiency in waveguide number, which satisfies:
where k 2 pi/lambda is wave number, lambda 1550nm, r is radius of the object to be measured, and epsilonpAnd εmIs the dielectric constant, eta, of the nanoparticle to be measured and the surrounding environment, respectivelycShowing the influence of the relative position between the nano-particles to be detected and the signal waveguide on the coupling efficiency.
The beat light and the reference light coming directly from the laser are fed to a balance detector, I when the reference light is equal to the DC component of the beat lightprobeηs+Ilocal＝IrefAnd the balance detector only outputs a radio frequency signal, namely:
where z is 50 Ω is the matching impedance of the transmission line, RBPDIs the responsivity coefficient of the balanced detector,
is an ideal case to balance the output of the detector. Wherein information about the nanoparticle to be measured is loaded on the amplitude of the radio frequency signal. In contrast to monitoring the transmission spectrum of scattered light directly, in the waveguide heterodyne sensor of the present invention, the weak scattered signal is amplified by a factor of
Because the inputs of the balance detectors cannot be completely equal, in the signal extraction process, the scheme of a radio frequency amplifier and a high-pass filter is adopted, the amplification of radio frequency signals and the suppression of low-frequency noise are realized, and the signal-to-noise ratio is greatly improved. The filtered signal is represented as:
wherein G isampThe gain of the amplifier is about 29dB, LfilterThe insertion loss of the high-pass filter is about 0.5 dB. The signal amplitude is again amplified by a factor of about 630 times by the electrical section.
Based on the invention, the ultrahigh-sensitivity extraction of the weak signal can be realized. Meanwhile, the structure based on the integrated silicon-based waveguide has the characteristics of small chip size, large-scale processing and insensitivity to process tolerance. On the basis, in order to enhance the efficiency of the sensing signal, the area of the sensing area is widened through the form of the cascade beam splitter, and meanwhile, based on the characteristics of the sensing signal in the extraction process, a scheme of radio frequency signal multiplexing and demultiplexing is provided to realize the real-time and rapid detection of the multipath characteristic signals.
Therefore, the heterodyne waveguide-based integrated heterodyne sensor can realize fast and stable nanoparticle detection, and becomes the research content of the invention.
Based on the above description, referring to fig. 1, fig. 1 is a schematic structural diagram of a nanoparticle sensor according to an embodiment of the present invention, where the nanoparticle sensor shown in fig. 1 includes: a silicon-based vertical heterodyne waveguide structure;
the silicon-based vertical heterodyne waveguide structure comprises a probe waveguide and a signal waveguide which are vertically arranged, and a sensing area is formed at the intersection of the probe waveguide and the signal waveguide; inputting local oscillation light as a local oscillation signal of the sensing area in the signal waveguide; in the probe waveguide, inputting probe light for interacting with the nano-particles to be detected in the sensing area; the probe light and the local oscillator light are coupled in the sensing area;
when the nano particles to be detected enter the sensing area, the signal waveguide collects probe light scattered after the interaction between the nano particles to be detected and the probe light, and outputs beat frequency signals generated by coupling the local oscillator light and the scattered probe light.
The nanoparticles to be detected can be molecules, viruses and other nanoparticles.
Further, the nanoparticle sensor further includes:
and the signal processing unit is used for detecting the beat frequency signal and outputting a detection result.
Specifically, the signal processing unit is specifically configured to detect a change in intensity of the beat signal, scale information, and category information, and output a detection result.
Further, the nanoparticle sensor further comprises a balance detector, a high-pass filter and a radio frequency amplifier, wherein the balance detector and the radio frequency amplifier sequentially amplify the beat frequency signals before the signal processing unit detects the beat frequency signals, the balance detector further suppresses common mode noise, and the high-pass filters arranged in front of and behind the radio frequency amplifier are used for filtering low-frequency noise.
Further, the signal processing unit is specifically configured to obtain a positive correlation between the variation in the beat frequency signal and the radius of the nanoparticle to be detected, and determine the scale information of the nanoparticle to be detected based on the step variation determined by the positive correlation.
Further, the nanoparticle sensor is provided with a dilution and atomization unit, and the dilution and atomization unit is used for diluting and atomizing the nanoparticles to be detected before the nanoparticles to be detected enter the sensing area.
Further, the sensor is an integrated sensor fabricated based on standard Complementary Metal Oxide Semiconductor (CMOS) processing.
Therefore, the nano particle sensor provided by the embodiment of the invention can realize ultrahigh-sensitivity extraction of weak signals. Meanwhile, the structure based on the integrated silicon-based waveguide has the characteristics of small chip size, large-scale processing and insensitivity to process tolerance. The on-chip sensing with high signal-to-noise ratio and high sensitivity is realized by weak signal amplification and system noise suppression.
On the basis of the foregoing embodiments, please refer to fig. 2, fig. 2 is a diagram illustrating an optical path junction of a nanoparticle sensor according to an embodiment of the present inventionSchematic diagram. The light field structure diagram of fig. 2A is composed of a laser light source, three optical beam splitters, an acousto-optic modulator, and a radio frequency signal source. The emergent light of the laser light source mainly comprises two light fields, namely local oscillation light (f) according to the optical frequency classification after passing through the beam splitter array0) And probe light (f)0+fRF，fRF80.15 MHz). The local oscillator light and the probe light are respectively coupled to the optical field distribution of the sensing area formed on the chip through a grating in a Transverse Electromagnetic (TE) mode. Part of the local oscillator light and part of the probe light are sent to the balanced detector and the reference detector 2 in fig. 3, respectively, to be used as reference signals for real-time signal normalization. FIG. 2B shows a schematic diagram of the operation of an on-chip heterodyne waveguide sensor (same as FIG. 1). Nanoscale particles such as molecules, viruses, etc. dispersed in a gas are transferred to the vicinity of the intersection sensing region by a sample delivery system (e.g., a glass tube). And the probe light scattered by the sample to be detected is collected by the signal waveguide and then emitted. Due to the introduction of the nano particles, probe light and local oscillator light simultaneously appear in the signal waveguide, the two optical fields interfere to form signal light with radio frequency envelope, and the signal light is output from the on-chip grating and enters a signal acquisition system.
Referring to fig. 3, fig. 3 is a schematic diagram of a beat signal extraction system cooperating with a heterodyne waveguide sensor according to an embodiment of the present invention. The signal light and the reference light enter the balanced detector to generate radio frequency output. The reference optical power is set to be close to the signal optical power, so that the suppression of direct-current components in the electric signals is realized, and the common-mode noise of a part of lasers is suppressed. The output of the balanced detector enters a high-pass filter (>55MHz) to achieve a further suppression of low frequency signals. To achieve real-time recording of the signal, the filtered rf signal is amplified again by an rf amplifier (29dB gain). The amplified signals are respectively equal to the two paths of frequencies (f)LO80.18MHz) but 90 degrees out of phase. The mixed output contains two frequency components, namely a sum frequency component (f)ELO+fRF) Sum and difference frequency component (f)ELO-fRF). After the mixed output signal passes through a low-pass filter (50kHz) in the acquisition card, only the difference frequency component is recordedThe results are reported as:
wherein the content of the first and second substances,
respectively representing two paths of beat frequency signals with orthogonal phases in the collected signals; f. ofELO-fRF30kHz is the frequency of a weak signal, phiELOIs the phase of the electrical local oscillator, and delta phi is the initial optical phase difference of the local oscillator light and the probe light;
is the amplitude of the beat frequency signal, containing information about the nanoparticle to be extracted, where AERepresenting the electrical gain in the system, IprobeAnd IlocalRespectively representing the instantaneous light intensity of the probe light and the local oscillation light input to the chip; etasRepresenting the scattering and collection efficiencies associated with nanoparticle and signal waveguide evanescent field distributions.
To extract etasThe change of (2) needs to go through three extraction processes: 1. collected signals
And
calculating the sum of squares and filtering out the carrier waves in the acquired signals; 2. the signals after carrier filtering are respectively normalized with the outputs of the reference detector 1 and the reference detector 2 which record the signals at the same time, and the instantaneous I is processedprobeAnd IlocalRemoving the influence of jitter; 3. because the time scale of the particle-related signal is in the order of 100ms, the high-frequency noise is further inhibited through 50Hz mean filtering, and meanwhile, the signal point is realizedThe sampling of (2) reduces the data volume, and is convenient for real-time recording and analysis.
Referring further to fig. 4, fig. 4 is a graph illustrating a comparison experiment result of a particle signal source according to an embodiment of the present invention. When samples to be detected (with the radius of 40nm) are respectively placed in different waveguide areas, the signal intensity changes of the local oscillator light (A), the probe light (B) and the scattering probe light (C) are respectively influenced, and it can be seen that only when the intensity of the scattering probe light changes, obvious step signals can be observed in the extracted signals. This method (third row of fig. 4) is also compared with the conventional method of monitoring the transmission spectrum loss (second row of fig. 4). Compared with the signals acquired at the same time, the method provided by the invention has better noise performance compared with the original scheme, and can realize the capability of detecting particles with smaller sizes.
Referring to fig. 5, fig. 5 is a schematic diagram illustrating signal intensity variations caused by standard particles with different radii according to an embodiment of the present invention. In order to verify the granularity identification capability of the sensor, the invention detects the standard polystyrene microspheres with different radius sizes. Fig. 5A-5C show a segment of the real-time signal for particles with radii of 30, 41 and 55nm, respectively, and it is evident that the step height variation induced by the particles increases significantly with the radius of the particles. Fig. 5D-5F are graphs showing the variation of the difference in the real-time signal strength corresponding to fig. 5A-5C, respectively. As can be seen from fig. 5A and 5D, the step signal can be identified and extracted even when the particle radius is only 30nm, and has an extremely high signal-to-noise ratio (11.7 dB). Therefore, the signal acquired by the sensor has extremely high signal-to-noise ratio.
Referring to fig. 6, fig. 6 is a schematic diagram of a calculation result of performing finite element simulation analysis on a light field in a sensing region of a sensor according to an embodiment of the present invention. In the finite element simulation, the collection of scattered light in the signal waveguide is mainly considered, and the calculation result is normalized with the electrical parameters of the system and the noise level. From the fitted curve, it can be seen that the beat intensity variation caused by different sized particles exhibits a variation relationship of about 3 power. By estimating the noise of the system of the invention, the expected particle detection limit is about 18nm radius particles, so the sensor has ultrahigh sensitivity characteristic.
Referring to fig. 7, fig. 7 is a schematic diagram of improving the probing efficiency based on the probe optical field expansion scheme according to an embodiment of the present invention, in which an on-chip waveguide beam splitting unit (fig. 7A) forms a probe waveguide array to realize expansion of a probe field. Compared with the structure in FIG. 2, the sensor after the light field expansion has greatly improved crosstalk efficiency. Fig. 7B shows the distribution of signal time intervals measured for 1 probe waveguide and 9 probe waveguide extensions in the same sample concentration for the two dark and light colored dots, respectively. It can be seen by exponential curve fitting that the characteristic time interval for signal appearance decreases from 2.97s to 0.96 s. Compared with a single waveguide sensor, the probe field expansion scheme has the advantage that the collection efficiency is improved by about 3 times. The sensor of the present invention can achieve a faster response characteristic.
Referring further to fig. 8, fig. 8 is a schematic diagram of a sensor and microfluidic based combination according to an embodiment of the present invention. By integrating microfluid (including microfluidic side walls and microfluidic chambers) on the sensing area, the surface of the sensing area is specially processed based on specific receptors and specific molecules, and the specifically processed sensor can realize specific monitoring on different types of biological particles (such as viruses, nucleic acids and proteins).
Referring to fig. 9, an embodiment of the present invention discloses a nanoparticle detection method, including:
901. detecting whether the nano particles enter a sensing area of a sensor, wherein the sensor comprises a silicon-based vertical heterodyne waveguide structure, the silicon-based vertical heterodyne waveguide structure comprises a probe waveguide and a signal waveguide which vertically intersect, and the intersection of the probe waveguide and the signal waveguide forms the sensing area; inputting local oscillation light as a local oscillation signal of the sensing area in the signal waveguide; in the probe waveguide, inputting probe light for interacting with the nano-particles to be detected in the sensing area; the probe light and the local oscillator light are coupled in the sensing area;
902. if the nano particles are detected to enter the sensing area, collecting probe light scattered after the nano particles and the probe light interact;
903. outputting the beat frequency signal generated by coupling the local oscillation light and the scattered probe light;
904. and detecting the beat frequency signal and outputting a detection result.
When no sample to be detected (nano particles to be detected) exists in the sensor, only a small amount of probe light is scattered to enter the signal waveguide due to the orthogonal waveguide structure, and after the nano particles to be detected enter the sensing area, the nano particles to be detected are scattered in the space under the excitation of the probe light due to the Rayleigh scattering principle, and a part of the scattered probe light is collected by the signal waveguide, so that beat frequency signals of the local oscillator light and the probe light are generated in the output of the signal waveguide.
The detecting the beat frequency signal and outputting the detection result in the step 904 includes:
and detecting the strength change, the scale information and the type information of the beat frequency signal, and outputting a detection result.
The detecting of whether the nanoparticles enter the sensing area of the sensor in the above step 901 previously includes:
and carrying out dilution and atomization treatment on the nano particles.
Specifically, when the nanoparticles are measured, the nanoparticles need to be uniformly dispersed in the air by means of dilution and atomization, then the air containing the dispersed particles is sent to a sensing area of the sensor by an air pump through a glass tube or the like, the light intensity change of the probe caused by the particles is reflected in the beat frequency signal in the signal waveguide, and the detection of the nanoparticles and the extraction of the relevant characteristics of the particles can be realized by monitoring the intensity change of the beat frequency signal in real time.
For a specific description of the nanoparticle detection method according to the embodiment of the present invention, reference may be made to the scheme of the nanoparticle sensor, and details are not described here.
The nano particle detection method provided by the embodiment of the invention can realize ultrahigh sensitivity extraction of weak signals. Meanwhile, the structure based on the integrated silicon-based waveguide has the characteristics of small chip size, large-scale processing and insensitivity to process tolerance. The on-chip sensing with high signal-to-noise ratio and high sensitivity is realized by weak signal amplification and system noise suppression.
Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.
Claims (10)
1. A nanoparticle sensor, comprising:
a silicon-based vertical heterodyne waveguide structure;
the silicon-based vertical heterodyne waveguide structure comprises a probe waveguide and a signal waveguide which are vertically arranged, and a sensing area is formed at the intersection of the probe waveguide and the signal waveguide; inputting local oscillation light as a local oscillation signal of the sensing area in the signal waveguide; in the probe waveguide, inputting probe light for interacting with the nano-particles to be detected in the sensing area; the probe light and the local oscillator light are coupled in the sensing area;
when the nano particles to be detected enter the sensing area, the signal waveguide collects probe light scattered after the interaction between the nano particles to be detected and the probe light, and outputs beat frequency signals generated by coupling the local oscillator light and the scattered probe light.
2. The nanoparticle sensor according to claim 1, further comprising:
and the signal processing unit is used for detecting the beat frequency signal and outputting a detection result.
3. The nanoparticle sensor according to claim 2, wherein the signal processing unit is specifically configured to detect a change in intensity of the beat signal, scale information, and species information, and output a detection result.
4. The nanoparticle sensor according to claim 3, further comprising a balance detector, a high pass filter and a radio frequency amplifier, wherein the balance detector and the radio frequency amplifier amplify the beat frequency signal in sequence before the signal processing unit detects the beat frequency signal, the balance detector further suppresses common mode noise, and the high pass filters disposed in front of and behind the radio frequency amplifier are configured to filter low frequency noise.
5. The nanoparticle sensor according to claim 3, wherein the signal processing unit is specifically configured to obtain a positive correlation between the variation in the beat signal intensity and the radius of the nanoparticle to be detected, and determine the scale information of the nanoparticle to be detected based on the step variation determined by the positive correlation.
6. The nanoparticle sensor according to claim 1, wherein the nanoparticle sensor is provided with a dilution and atomization unit, and the dilution and atomization unit is used for performing dilution and atomization treatment on the nanoparticles to be detected before the nanoparticles to be detected enter the sensing area.
7. The nanoparticle sensor according to claim 1, wherein the sensor is an integrated sensor fabricated based on standard Complementary Metal Oxide Semiconductor (CMOS) processing.
8. A method for nanoparticle detection, comprising:
detecting whether the nano particles enter a sensing area of a sensor, wherein the sensor comprises a silicon-based vertical heterodyne waveguide structure, the silicon-based vertical heterodyne waveguide structure comprises a probe waveguide and a signal waveguide which are vertically arranged, and a sensing area is formed at the intersection of the probe waveguide and the signal waveguide; inputting local oscillation light as a local oscillation signal of the sensing area in the signal waveguide; in the probe waveguide, inputting probe light for interacting with the nano-particles to be detected in the sensing area; the probe light and the local oscillator light are coupled in the sensing area;
if the nano particles are detected to enter the sensing area, collecting probe light scattered after the nano particles and the probe light interact;
outputting the beat frequency signal generated by coupling the local oscillation light and the scattered probe light;
and detecting the beat frequency signal and outputting a detection result.
9. The nanoparticle detection method according to claim 8, wherein the detecting the beat signal and outputting a detection result comprises:
and detecting the strength change, the scale information and the type information of the beat frequency signal, and outputting a detection result.
10. The method for detecting nanoparticles as claimed in claim 8, wherein the detecting whether the nanoparticles enter the sensing area of the sensor comprises:
and carrying out dilution and atomization treatment on the nano particles.
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