CN114414043A - Device and method for measuring intensity distribution of optical field based on optical tweezers and electric field force - Google Patents
Device and method for measuring intensity distribution of optical field based on optical tweezers and electric field force Download PDFInfo
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- 230000003287 optical effect Effects 0.000 title claims abstract description 77
- 230000005684 electric field Effects 0.000 title claims abstract description 53
- 238000012576 optical tweezer Methods 0.000 title claims abstract description 45
- 238000000034 method Methods 0.000 title claims abstract description 15
- 239000002245 particle Substances 0.000 claims abstract description 48
- 238000006073 displacement reaction Methods 0.000 claims abstract description 34
- 238000005259 measurement Methods 0.000 claims abstract description 14
- 230000001105 regulatory effect Effects 0.000 claims abstract description 3
- 239000002105 nanoparticle Substances 0.000 claims description 111
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 10
- 235000012239 silicon dioxide Nutrition 0.000 claims description 5
- 239000000377 silicon dioxide Substances 0.000 claims description 5
- 238000010606 normalization Methods 0.000 claims description 4
- 238000012545 processing Methods 0.000 claims description 4
- 230000001276 controlling effect Effects 0.000 abstract 1
- 239000004005 microsphere Substances 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000011550 stock solution Substances 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
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- 238000011161 development Methods 0.000 description 1
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- 239000007772 electrode material Substances 0.000 description 1
- 238000004070 electrodeposition Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000012625 in-situ measurement Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
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- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/02—Details
- G01J1/0266—Field-of-view determination; Aiming or pointing of a photometer; Adjusting alignment; Encoding angular position; Size of the measurement area; Position tracking; Photodetection involving different fields of view for a single detector
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- G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
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Abstract
The invention discloses a device and a method for measuring the intensity distribution of an optical field based on optical tweezers and electric field force. The invention uses the optical tweezers to suspend the nanometer particles, places the particles in the optical field to be measured, applies electric field to the particles, calibrates the parameters of the nanometer particles, and obtains the relation of the nanometer particles deviating from the center displacement of the optical trap of the optical tweezers by regulating and controlling different electric field forces. Because the size of the nanometer particles is far smaller than the wavelength of the light field to be measured, Rayleigh scattering occurs when the nanometer particles are placed in the light field to be measured, the intensity of scattered light is in direct proportion to the intensity of the light field at the position of the light field to be measured where the nanometer particles are located, the photoelectric detector is used for collecting scattered light signals of the nanometer particles, the intensity of the light field at the position is obtained through calculation, electric field forces in different directions and different sizes are applied to change the position of the nanometer particles in the light field to be measured, the scattered light signals at different positions are collected, and the measurement of the intensity distribution of the light field can be realized. The measuring device and the measuring method can provide higher spatial resolution and measuring precision.
Description
Technical Field
The invention belongs to the field of optical field intensity distribution measurement, and particularly relates to a device and a method for measuring optical field intensity distribution based on optical tweezers and electric field force.
Background
With the development of laser technology, the laser technology is widely applied to the fields of industry, agriculture, military, astronomy and the like, one of the core indexes influencing the application of the laser technology is light field intensity distribution, the traditional light field intensity distribution measurement method is generally a CCD (charge coupled device) imaging method, an area array CCD detector is utilized to measure the light field intensity distribution of a visible light and near infrared laser light field, and even if a high-performance high-resolution CCD detector is selected, the spatial resolution of the measurement is limited by the pixel of the detector, and the maximum value is micron level at present. For the measurement of the optical field distribution with the size from submicron to nanometer, the existing means can not accurately realize the measurement of high spatial resolution.
Disclosure of Invention
In order to overcome the defect of spatial resolution in the prior art for measuring the intensity distribution of the laser light field, the invention provides a novel measuring means of the intensity distribution of the light field and provides higher spatial resolution.
A method for measuring the intensity distribution of an optical field based on optical tweezers and electric field force comprises the following steps:
1) calibration: suspending nanoparticles by using optical tweezers, placing the nanoparticles in an optical field, applying an electric field to the nanoparticles, calibrating parameters of the nanoparticles, and obtaining a relation of the magnitude of the electric field force corresponding to the displacement of the nanoparticles from the central position of an optical trap of the optical tweezers by regulating the magnitude of the electric field force;
2) measurement: the nanometer particles are placed in a light field to be detected, because the size of the nanometer particles is far smaller than the wavelength of the light field to be detected, the nanometer particles can generate Rayleigh scattering when placed in the light field to be detected, the light intensity of scattered light is in direct proportion to the light intensity of the light field to be detected where the nanometer particles are located, a photoelectric detector is used for collecting scattered light signals of the nanometer particles, and the light field intensity of the position is calculated; and applying electric fields with different directions and sizes to change the position of the nano particles in the light field to be measured, collecting scattered light signals of different positions, and calculating to realize the measurement of the light field intensity distribution of the light field to be measured.
In the above technical solution, further, the step 1) specifically includes:
the laser observation card is utilized to determine the positions of the optical trap of the optical tweezers and the optical field to be detected, the optical trap area of the optical tweezers is placed in the optical field to be detected, the optical trap of the optical tweezers captures nanoparticles and applies a direct current voltage with a determined size after the nanoparticles are stabilized, and the nanoparticles generate displacement in the optical trap area of the optical tweezers under the action of an electric field force formed by the direct current voltage. The displacement generated by applying different electric field forces to the nanoparticles is different, and the linear relation between the magnitude of the applied direct current voltage and the displacement of the nanoparticles with fixed charge quantity can be calibrated before experiments. Detecting the change of displacement signals of the nanometer particles after applying electric field force with certain magnitude, resolving and determining the charge quantity of the particles, and calculating and determining a relational expression D (V) between the applied direct current voltage (V) and the displacement (D) of the nanometer particles deviating from the center position of the optical trap of the optical tweezers.
Further, the step 2) specifically comprises the following steps:
21) setting the DC voltage source to 0, recording the initial position L0 of the nanoparticles, collecting the light scattered by the nanoparticles, and recording the intensity of the scattered light S0; changing the magnitude of the applied direct current voltage, and substituting the voltage into a displacement relation formula D (V) between the applied voltage and the central position of the optical trap of the optical tweezers and voltage into V1, V2 and V3 … Vn (n represents the number of times of voltage change), sequentially recording the positions L1, L2 and L3 … Ln of the nanoparticles, simultaneously recording the scattered light intensity S1, S2 and S3 … Sn of the nanoparticles, and after the linear direction scanning is completed, setting a direct current voltage source to zero and restoring the nanoparticles to the initial position;
22) changing the direction of the electric field by taking the nano particles as the center in the cross section of the optical field to be detected, and repeating the step 2) until the scanning of the optical field to be detected is completed;
23) and carrying out normalization processing on the scattered light intensity of the nanoparticles to obtain the light field intensity distribution of the light field to be measured in the three-dimensional space.
The invention also provides a device for measuring the intensity distribution of the optical field based on the optical tweezers and the electric field force, which comprises a laser, a first collimating lens, a second collimating lens, a first reflector, an objective lens, an electrode, a nanoparticle, a third collimating lens, a four-quadrant detector, a direct-current voltage source, a photoelectric detector and an upper computer;
the laser emits trapped laser, beam expanding collimation is carried out through a first collimating lens and a second collimating lens, the trapped laser sequentially passes through a first reflector, a second reflector and an objective lens to converge to form an optical tweezers, nanoparticles are trapped in an optical trap of the optical tweezers and stably suspended in the air, the nanoparticles collimate scattered light B of the trapped laser through a third collimating lens and are collected by a four-quadrant detector, formed voltage data are resolved by an upper computer, and information of the nanoparticles is obtained; scattered light C generated by the nanoparticles at different positions in the light field A to be detected is collected by a photoelectric detector, and formed data is processed by an upper computer; the direct current voltage source provides stable voltage output at two ends of the electrode to form a stable electric field, the nanoparticles are charged and stressed in the electric field to generate displacement, and the displacement is controlled by adjusting the magnitude of the direct current voltage to realize the movement of the nanoparticles at different positions in the optical field to be detected;
the device can measure the light field intensity distribution by adopting the method.
Furthermore, the nanometer particles are optical uniform medium spheres, the diameter of the nanometer particles is less than 200 nanometers, and the material is silicon dioxide.
Furthermore, the electrodes can be placed at different positions and in different directions according to the difference of the light field A to be detected.
Furthermore, the photoelectric detector collects the scattered light C of the nano particles, and the scattering angle is selected to be 60-120 degrees.
The invention has the beneficial effects that:
the invention realizes the measurement of the point position light field intensity by utilizing the Rayleigh scattering phenomenon generated by the optical tweezers suspending nanoparticles in the light field to be measured, realizes the non-contact nanometer-level position movement of the nanoparticles through the electric field force, and scans the light field intensity at different positions, thereby realizing the in-situ measurement of the light field intensity distribution, having the nanometer-level spatial resolution and being used for the precise measurement of the micron-level small-scale light field intensity distribution.
Drawings
FIG. 1 is a schematic diagram of the apparatus of the present invention;
FIG. 2 is a schematic diagram of the movement of electrodes in the cross section of the optical field to be measured;
FIG. 3 is a diagram of a normalized light field intensity distribution;
the device comprises a laser 1, a first collimating lens 2, a second collimating lens 3, a first reflector 4, a second reflector 5, an objective lens 6, an electrode 7, nanoparticles 8, a third collimating lens 9, a four-quadrant detector 10, a direct-current voltage source 11, a photoelectric detector 12 and an upper computer 13.
Detailed Description
The invention is further illustrated below with reference to the figures and examples.
The invention discloses a method for measuring intensity distribution of an optical field based on optical tweezers and electric field force. When the nanoparticles are located in the laser field to be measured, if the size of the nanoparticles is far smaller than the laser wavelength, rayleigh scattering occurs, and the light intensity I of scattered light is as follows:
wherein IAThe light intensity of the light field position where the nanometer particles are located, theta is a scattering angle, namely an included angle between the detection direction of the photoelectric detector and the propagation direction of the light beam, d is the distance between the photoelectric detector and the nanometer particles, lambda is the light wavelength, n is the relative refractive index between the particles and the environment medium, and r is the radius of the particles. From the above equation, the scattered light intensity is proportional to the light intensity at the location of the particle. The method comprises the steps of capturing nanoparticles through an optical trap of an optical tweezers, placing the nanoparticles in an optical field to be detected, applying an electric field through electrodes, enabling the nanoparticles to generate electric field force in an electrified mode, changing the positions of the nanoparticles in the optical field to be detected under the action of the electric field force, collecting scattered light of the nanoparticles by using a photoelectric detector, changing the direction and the size of the electric field, changing the positions of the nanoparticles, recording the light intensity of the scattered light at different positions, and performing measurement on the light intensity of the scattered light at different positionsAnd scanning point by point in the space, and finally calculating by an upper computer to complete the measurement of the intensity distribution of the light field to be measured.
The invention selects particles with the diameter below 200nm, the near infrared band can meet the Rayleigh scattering condition, as the nano particles can adsorb charges, after the nano particles are captured in the optical trap area of the optical tweezers by laser, a certain electric field is applied to the nano particles, the nano particles can generate displacement in the optical trap of the optical tweezers under the action of the electric field force, and the displacement can be obtained by collecting particle signals by a four-quadrant detector and resolving. Since the intensity of the electric field generated by the electrodes depends on the voltage across the electrodes, theoretically there is a correspondence between the displacement D of the particles and the voltage V across the electrodes:
D∝βV
wherein beta is a coefficient to be calibrated, the position information corresponding to the nano particles is obtained by changing the voltage at two ends of the electrode before measurement, and the coefficient beta between the displacement D and the voltage V at two ends of the electrode is calibrated. Since the voltage can be adjusted to mV or even μ V, the spatial resolution of the present invention can theoretically be infinitely small, and finally the nanoparticle displacement D is limited by the size of the nanoparticles and the size of the optical trap trapping region of the optical tweezers.
As shown in fig. 1, the device for measuring intensity distribution of an optical field based on optical tweezers and electric field force of the present invention includes a laser 1, a first collimating lens 2, a second collimating lens 3, a first reflector 4, a second reflector 5, an objective lens 6, an electrode 7, nanoparticles 8, a third collimating lens 9, a four-quadrant detector 10, a dc voltage source 11, a photodetector 12, and an upper computer 13.
The laser 1 emits trapped laser, beam expanding collimation is carried out through the first collimating lens 2 and the second collimating lens 3, the trapped laser sequentially passes through the first reflector 4, the second reflector 5 and the objective lens 6 to form optical tweezers, the nanoparticles 8 are trapped in optical traps of the optical tweezers and stably suspended in air, the nanoparticles 8 collimate scattered light B of the trapped laser through the third collimating lens 9 and are collected by the four-quadrant detector 10, and formed voltage data are processed by the upper computer 13; scattered light C generated by the nano particles 8 in the light field A to be detected is collected by a photoelectric detector 12, and formed data is processed by an upper computer 13; the direct current voltage source 11 provides stable voltage output at two ends of the electrode 7 to form a stable electric field, the nanoparticles 8 are charged, and are stressed in the electric field to generate displacement, and the displacement is controlled by adjusting the magnitude of the direct current voltage, so that the displacement control of the nanoparticles 8 in the optical field A to be detected is realized.
The electrode 7 can be customized according to the electric field a to be tested and the test requirements, and is not limited to the pattern shown in fig. 1, and the material is red copper or other electrode materials.
The nanometer particle 8 is an optical homogeneous medium ball with diameter below 200nm, the particle is spherical, the material is silicon dioxide, and the surface is charged.
The four-quadrant detector 10 collects far-field interference signals generated by light scattered by the nanoparticles 11 and captured light, and is used for acquiring information for resolving the nanoparticles 11 and calibrating the relationship between the magnitude of the applied electric field voltage and the displacement of the nanoparticles 11.
The photoelectric detector 12 collects the scattered light C of the nano particles 8 to the light field A to be detected, and the detection wavelength of the scattered light C needs to be matched with the wavelength of the light field A to be detected; the scattering angle of the collected scattered light C can be selected from 0 ° to 180 °, preferably from 60 ° to 120 °. Forward scattered light is obtained when the scattering angle is 0 degrees, forward side scattered light is obtained when the scattering angle is 90 degrees, and backward (back) scattered light is obtained when the scattering angle is 180 degrees; side scattered light is generally used, interference of a light field can be eliminated compared with forward scattered light, and a detection structure is simpler compared with backward scattered light.
The photodetector 12 is used to obtain a light intensity signal, and is not limited to CCD or CMOS, and may obtain a physical quantity directly related to the light intensity, such as light intensity, light power, brightness, and the like, where S is the physical quantity and I is the light intensity, S ∈ I is satisfied.
The voltage source is utilized to generate potential difference at two ends of the electrodes, an electric field is formed between the electrodes, electric field force is generated on the charged nanoparticles, the nanoparticles move and are relatively stable at a position balanced with the gradient force of the optical trap, the electric field force is adjusted by adjusting the voltage and the direction at two ends of the electrodes, so that the positions of the nanoparticles in the optical field to be detected are controlled, and the optical field to be detected is scanned.
The optical wavelength of the light field to be detected is in a near infrared band, the size of the nanometer particles 11 is below 200nm, the size of the nanometer particles is far smaller than the optical wavelength, the nanometer particles generate Rayleigh scattering, and the light intensity of scattered light and the light intensity I at the positions of the nanometer particlesAIs in direct proportion.
The measuring method comprises the following measuring steps:
(1) the laser observation card is utilized to determine the positions of the optical trap of the optical tweezers and the optical field to be measured, the whole device is moved to place the optical trap area in the optical field to be measured, after the optical trap of the optical tweezers captures the nanoparticles and is stable, direct current voltage with a determined size is applied to the electrodes, the electrodes generate an electric field to generate electric field force with a certain size on the charged nanoparticles, and the nanoparticles generate displacement in the optical trap of the optical tweezers under the action of the electric field force. The displacement generated by applying different electric field forces to the nanoparticles is different, and the linear relation between the magnitude of the applied direct current voltage and the displacement of the fixed-charge-amount small ball can be calibrated before experiments. In the experiment, a four-quadrant detector is used for detecting the change of a displacement signal of the nanometer particles after an electric field with a certain size is applied, an upper computer is used for resolving and determining the charge quantity of the nanometer particles, and the relation D (V) between the applied voltage (V) and the displacement (D) of the nanometer particles is obtained (V represents the applied voltage);
(2) setting the DC voltage source to 0, recording the initial position L0 of the nanoparticles, collecting the nanoparticles scattered light by a photoelectric detector, and recording the output value S0; changing the magnitude of the applied direct current voltage, and substituting the voltage into a relation D (V) between the applied voltage and the displacement of the nanoparticles by V1, V2 and V3 … Vn (n represents the number of times of voltage change), sequentially recording the positions L1, L2 and L3 … Ln of the microspheres, simultaneously recording the output values S1, S2 and S3 … Sn of the scattered light intensity of the particles by the photoelectric detector, and after the scanning in the linear direction is completed, setting the direct current voltage source to zero, and restoring the nanoparticles to the initial position.
(3) Referring to fig. 2, in the cross section of the optical field to be measured, the electrode position is changed with the nanoparticle as the center, and the step (2) is repeated until the scanning of the optical field to be measured is completed;
(4) and (3) carrying out normalization processing on the output value of the detector (namely the intensity of the nano particle scattered light) to obtain the relative light field intensity distribution of the light field to be detected in the three-dimensional space.
Application examples
The laser 1 can adopt a 1064nm continuous laser, and the output of the laser is stable in the implementation process, i.e. the optical power of the captured light is kept stable.
The nano-particles 8 are silicon dioxide microspheres with the nominal diameter of 150nm, the standard deviation of the particle size of the silicon dioxide microspheres is less than 5nm, the stock solution of the nano-particles is diluted by alcohol, atomized in the air by an atomizer and captured by an optical trap, and whether the nano-particles are single particles is judged by signals of a four-quadrant detector.
The photodetector 12 may be an optical power meter, which is 10mm away from the nanoparticles 11 and measures the intensity of the scattered light at a selected scattering angle of 60 °.
The wavelength of the light field A to be measured is 808nm, and the electrode direction is vertical to the light field propagation direction.
The implementation steps are as follows:
(1) starting a 1064nm laser, forming a stable optical tweezer optical trap after passing through an objective lens, determining the position of an optical field to be detected by using a laser observation card, and moving the optical trap to the optical field to be detected;
(2) diluting the nanoparticle stock solution with alcohol, atomizing the diluted nanoparticle stock solution near an optical trap of optical tweezers by using an atomizer, waiting for the optical trap to capture nanoparticles, judging whether the nanoparticles are captured or not and whether the captured nanoparticles are single nanoparticles or not by observing signals of a four-quadrant detector, and calibrating the motion information of the nanoparticles by the signals of the four-quadrant detector;
(3) applying voltages with different sizes to two ends of the electrode, calibrating a relation D (V) between the applied voltage (V) and the nanoparticle displacement (D) through signals collected by a four-quadrant detector, wherein the V represents the applied voltage;
(4) setting the DC voltage source to 0, recording the initial position L0 of the nanoparticles, collecting the nanoparticles scattered light by a photoelectric detector, and recording the output value S0; changing the magnitude of the applied direct current voltage, and substituting the voltage into a relation D (V) between the applied voltage and the displacement of the nanoparticles by V1, V2 and V3 … Vn (n represents the number of times of voltage change), sequentially recording the positions L1, L2 and L3 … Ln of the microspheres, simultaneously recording the output values S1, S2 and S3 … Sn of the scattered light intensity of the nanoparticles by a photoelectric detector, and after the scanning in the linear direction is completed, setting the direct current voltage source to zero and restoring the nanoparticles to the initial position;
(5) changing the position of the electrode by taking the nano particles as centers in the cross section of the light field to be detected, and repeating the step (3) until the scanning of the light field to be detected is completed;
(6) and carrying out normalization processing on the output value of the detector to obtain the relative light field intensity distribution of the light field to be detected in the three-dimensional space. Referring to fig. 3, taking a cross section of the light field to be measured as an example, in the scanning graph of the relative light intensity distribution, the x axis and the y axis are section coordinate axes, and the z axis is the relative intensity of the light field.
Finally, it should be noted that the above examples and illustrations are only intended to illustrate the technical solutions of the present invention and are not intended to limit the present invention. It will be understood by those skilled in the art that various modifications and equivalent arrangements may be made without departing from the spirit and scope of the present disclosure and it should be understood that the present disclosure is to be limited only by the appended claims.
Claims (7)
1. A method for measuring the intensity distribution of an optical field based on optical tweezers and electric field force is characterized by comprising the following steps:
1) calibration: suspending nanoparticles by using optical tweezers, placing the nanoparticles in an optical field, applying an electric field to the nanoparticles, calibrating parameters of the nanoparticles, and obtaining a relation of the magnitude of the electric field force corresponding to the displacement of the nanoparticles from the central position of an optical trap of the optical tweezers by regulating the magnitude of the electric field force;
2) measurement: the nanometer particles are placed in a light field to be detected, because the size of the nanometer particles is far smaller than the wavelength of the light field to be detected, the nanometer particles can generate Rayleigh scattering when placed in the light field to be detected, the light intensity of scattered light is in direct proportion to the light intensity of the light field to be detected where the nanometer particles are located, a photoelectric detector is used for collecting scattered light signals of the nanometer particles, and the light field intensity of the position is calculated; and applying electric fields with different directions and sizes to change the position of the nano particles in the light field to be measured, collecting scattered light signals of different positions, and calculating to realize the measurement of the light field intensity distribution of the light field to be measured.
2. The method for measuring the intensity distribution of the optical field based on the optical tweezers and the electric field force according to claim 1, wherein the step 1) is specifically as follows:
1) the laser observation card is utilized to determine the positions of an optical trap of the optical tweezers and an optical field to be detected, an optical trap area of the optical tweezers is placed in the optical field to be detected, the optical trap of the optical tweezers captures nanoparticles and applies a direct current voltage with a determined size after the nanoparticles are stabilized, and the nanoparticles generate displacement in the optical trap area of the optical tweezers under the action of an electric field force formed by the direct current voltage; detecting the change of the displacement signal of the nanometer particle after applying certain electric field force, resolving and determining the charge quantity of the particle, and obtaining a relational expression D (V) between the applied direct current voltage V and the displacement D of the nanometer particle deviating from the center position of the optical trap of the optical tweezers.
3. The method according to claim 2, wherein the step 2) specifically comprises the following steps:
21) setting the DC voltage source to 0, recording the initial position L0 of the nanoparticles, collecting the light scattered by the nanoparticles, and recording the intensity of the scattered light S0; changing the magnitude of the applied direct current voltage, wherein V1, V2 and V3 … Vn, n represents the voltage change times, substituting the voltage into a displacement relation formula D (V) between the applied voltage and the position of the nanoparticle deviated from the center of the optical trap of the optical tweezers, sequentially recording the positions L1, L2 and L3 … Ln of the nanoparticle, simultaneously recording the scattered light intensity S1, S2 and S3 … Sn of the nanoparticle, after the linear direction scanning is completed, setting the direct current voltage source to zero, and restoring the nanoparticle to the initial position;
22) changing the direction of the electric field by taking the nano particles as the center in the cross section of the optical field to be detected, and repeating the step 2) until the scanning of the optical field to be detected is completed;
23) and carrying out normalization processing on the scattered light intensity of the nanoparticles to obtain the light field intensity distribution of the light field to be measured in the three-dimensional space.
4. A device for measuring the intensity distribution of an optical field based on optical tweezers and electric field force is characterized by comprising a laser, a first collimating lens, a second collimating lens, a first reflector, a second reflector, an objective lens, an electrode, nanoparticles, a third collimating lens, a four-quadrant detector, a direct-current voltage source, a photoelectric detector and an upper computer;
the laser emits trapped laser, beam expanding collimation is carried out through a first collimating lens and a second collimating lens, the trapped laser sequentially passes through a first reflector, a second reflector and an objective lens to converge to form an optical tweezers, nanoparticles are trapped in an optical trap of the optical tweezers and stably suspended in the air, the nanoparticles collimate scattered light B of the trapped laser through a third collimating lens and are collected by a four-quadrant detector, formed voltage data are resolved by an upper computer, and information of the nanoparticles is obtained; scattered light C generated by the nanoparticles at different positions in the light field A to be detected is collected by a photoelectric detector, and formed data is processed by an upper computer; the direct current voltage source provides stable voltage output at two ends of the electrode to form a stable electric field, the nanoparticles are charged and stressed in the electric field to generate displacement, and the displacement is controlled by adjusting the magnitude of the direct current voltage to realize the movement of the nanoparticles at different positions in the optical field A to be detected;
the device can be used to measure the light field intensity distribution using the method according to any of claims 1-3.
5. The apparatus of claim 4, wherein the nanoparticles are optically uniform dielectric spheres with a diameter of less than 200nm and are made of silicon dioxide.
6. The apparatus according to claim 4, wherein the electrodes are disposed at different positions and directions according to the optical field A to be measured.
7. The apparatus of claim 4, wherein the photodetector collects the scattered light C from the nanoparticles, and the scattering angle is selected from 60 ° to 120 °.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114859076A (en) * | 2022-07-06 | 2022-08-05 | 之江实验室 | Acceleration measurement method and device based on optical suspension multi-microsphere array |
| CN117629899A (en) * | 2024-01-26 | 2024-03-01 | 之江实验室 | Nanoparticle extinction section in-situ measurement method and device based on suspension optical tweezers |
| CN117647470A (en) * | 2024-01-29 | 2024-03-05 | 之江实验室 | Device for measuring far field of scattered field based on suspended optical tweezers and reciprocity theorem and application thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111551250A (en) * | 2020-07-13 | 2020-08-18 | 之江实验室 | Method and device for measuring light field distribution |
| CN111623871A (en) * | 2020-07-13 | 2020-09-04 | 之江实验室 | Method and device for measuring laser light field relative intensity distribution by using nano particles |
| CN112863728A (en) * | 2021-04-26 | 2021-05-28 | 之江实验室 | Electric field amount calibration-based multi-dimensional optical tweezers calibration device and method |
-
2021
- 2021-12-23 CN CN202111590873.9A patent/CN114414043A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111551250A (en) * | 2020-07-13 | 2020-08-18 | 之江实验室 | Method and device for measuring light field distribution |
| CN111623871A (en) * | 2020-07-13 | 2020-09-04 | 之江实验室 | Method and device for measuring laser light field relative intensity distribution by using nano particles |
| CN112863728A (en) * | 2021-04-26 | 2021-05-28 | 之江实验室 | Electric field amount calibration-based multi-dimensional optical tweezers calibration device and method |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114859076A (en) * | 2022-07-06 | 2022-08-05 | 之江实验室 | Acceleration measurement method and device based on optical suspension multi-microsphere array |
| CN114859076B (en) * | 2022-07-06 | 2022-10-21 | 之江实验室 | Acceleration measurement method and device based on optical suspension multi-microsphere array |
| CN117629899A (en) * | 2024-01-26 | 2024-03-01 | 之江实验室 | Nanoparticle extinction section in-situ measurement method and device based on suspension optical tweezers |
| CN117629899B (en) * | 2024-01-26 | 2024-06-07 | 之江实验室 | Nanoparticle extinction section in-situ measurement method and device based on suspension optical tweezers |
| CN117647470A (en) * | 2024-01-29 | 2024-03-05 | 之江实验室 | Device for measuring far field of scattered field based on suspended optical tweezers and reciprocity theorem and application thereof |
| CN117647470B (en) * | 2024-01-29 | 2024-06-07 | 之江实验室 | Device for measuring far field of scattered field based on suspended optical tweezers and reciprocity theorem and application thereof |
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