Abstract: The present application discloses a nanoparticle recognition device and method based on detection of scattered light with electric dipole rotation. According to the scattering model of nanoparticles, the in situ detection of particle morphology in an optical trap is realized by the methods of particle suspension control and scattered light detection and separation. Specifically, two linearly polarized laser beams are used, wherein the first laser beam suspends nanoparticles and rotates nanoparticles by adjusting the polarization direction; the polarization direction of the second linearly polarized light is unchanged, and scattered light in a specific dipole direction is excited; the change of the polarizability of the nanoparticles is deduced by monitoring the change of the light intensity of the scattered light excited by the second laser beam at the fixed position, so that particle morphology recognition is realized.

Abstract: A probe-based bidirectional electrophoretic force optical trap loading method includes steps of (1) detaching target particles from an upper electrode plate and capturing the target particles by a micro-scale probe based on a bidirectional electrophoretic force; (2) moving the probe with the target particles over an optical trap, applying a reverse electric field between the probe and the upper substrate electrode plate which is applied during a polar relaxation time of the target particles, and desorbing the target particles from the probe; and (3) turning on the optical trap, applying an electric field between the lower electrode plate and the upper electrode plate, adjusting the speed of the desorbed target particles through the electric field at which the optical trap is able to capture the desorbed target particles and the desorbed target particles moving to the effective capture range of the optical trap.

Abstract: A method for enhancing vacuum tolerance of optical levitation particles includes steps of: (1) turning on a trapping laser to form an optical trap, loading the particles to an effective capture region of the optical trap, and collecting scattered light signals; (2) turning on the preheating laser, and directing a preheating laser beam to the captured particles; (3) adjusting a power of the preheating laser until a particle heating rate is larger than a heat dissipation rate; (4) turning on the vacuum pump, and stopping evacuating when a vacuum degree is greater than a vacuum inflection point of a first reduction of the effective capture region of the optical trap; and (5) turning off the preheating laser when the scattered light signals collected by the photodetector no longer changes. The present invention improves a stable capture probability of the particles in high vacuum environment.

Abstract: A method for enhancing vacuum tolerance of optical levitation particles includes steps of: (1) turning on a trapping laser to form an optical trap, loading the particles to an effective capture region of the optical trap, and collecting scattered light signals; (2) turning on the preheating laser, and directing a preheating laser beam to the captured particles; (3) adjusting a power of the preheating laser until a particle heating rate is larger than a heat dissipation rate; (4) turning on the vacuum pump, and stopping evacuating when a vacuum degree is greater than a vacuum inflection point of a first reduction of the effective capture region of the optical trap; and (5) turning off the preheating laser when the scattered light signals collected by the photodetector no longer changes. The present invention improves a stable capture probability of the particles in high vacuum environment.

Abstract: A probe-based bidirectional electrophoretic force optical trap loading method includes steps of (1) detaching target particles from an upper electrode plate and capturing the target particles by a micro-scale probe based on a bidirectional electrophoretic force; (2) moving the probe with the target particles over an optical trap, applying a reverse electric field between the probe and the upper substrate electrode plate which is applied during a polar relaxation time of the target particles, and desorbing the target particles from the probe; and (3) turning on the optical trap, applying an electric field between the lower electrode plate and the upper electrode plate, adjusting the speed of the desorbed target particles through the electric field at which the optical trap is able to capture the desorbed target particles and the desorbed target particles moving to the effective capture range of the optical trap.

Abstract: Disclosed is an optical trap calibration apparatus and method based on variation of electric field by optical imaging of a nanoparticle. By means of a direct optical imaging method, a linear nanoparticle equilibrium position displacement under the action of a constant electric field is measured to realize calibration, thereby avoiding the introduction of error signals, and improving the reliability of differential calibration. The specific calibration method and apparatus of the present invention are not only suitable for calibration of electric field quantity, but also suitable for the calibration of other magnetic forces and the like. By means of the accurate calibration of mechanical quantity in the present invention, the development and application of the vacuum optical trap sensing technology can be promoted.

Abstract: Disclosed is a multi-dimensional optical tweezers calibration device based on electric field quantity calibration and a method thereof. The polarization-dependent characteristics of a tightly focused optical trap are utilized to realize triaxial electric field force calibration of particles through a one-dimensional electric field quantity calibration device. The method of the present application enables a particle electric field force calibration system to be compatible with particle delivery and particle detection systems; the device is simplified and calibration complexity is reduced.

Abstract: The present application discloses a nanoparticle recognition device and method based on detection of scattered light with electric dipole rotation. According to the scattering model of nanoparticles, the in situ detection of particle morphology in an optical trap is realized by the methods of particle suspension control and scattered light detection and separation. Specifically, two linearly polarized laser beams are used, wherein the first laser beam suspends nanoparticles and rotates nanoparticles by adjusting the polarization direction; the polarization direction of the second linearly polarized light is unchanged, and scattered light in a specific dipole direction is excited; the change of the polarizability of the nanoparticles is deduced by monitoring the change of the light intensity of the scattered light excited by the second laser beam at the fixed position, so that particle morphology recognition is realized.

Abstract: An electronic magnetometer and a method for measuring a magnetic field are provided. A Gunn diode with magnetic shielding and a Gunn diode without magnetic shielding generate different induced high-frequency oscillating currents in various environments. The high-frequency oscillating current of the Gunn diode with magnetic shielding and the high-frequency oscillating current of the Gunn diode without magnetic shielding are processed by circuits and subsequently compared. The difference of frequencies in the two currents is proportional to the magnitude of magnetic field, and the magnitude of magnetic field is obtained.

Abstract: A magnetic field based micro-vibration measurement device and a measuring therefore are provided, which are applied in a micro-vibration measurement technical field. Fluxgate sensors and a control processing circuit are included. Each of the fluxgate sensors is disposed with an excitation coil and an induction coil that are mutually corresponding; the control processing circuit includes: an excitation signal generating module, a frequency-selective amplifying module, a phase-sensitive rectifying module, a smooth filtering module an ambient magnetic field acquisition module, and a vibration data statistics module. Excitation coils generate excitation magnetic field signals according to the excitation signal sent from the excitation signal generating module the induction coils are for generating induced current signals according to the receive excitation magnetic field signal and the ambient magnetic field signal.

Abstract: A magnetic field based micro-vibration measurement device and a measuring therefore are provided, which are applied in a micro-vibration measurement technical field. Fluxgate sensors and a control processing circuit are included. Each of the fluxgate sensors is disposed with an excitation coil and an induction coil that are mutually corresponding; the control processing circuit includes: an excitation signal generating module, a frequency-selective amplifying module, a phase-sensitive rectifying module, a smooth filtering module an ambient magnetic field acquisition module, and a vibration data statistics module. Excitation coils generate excitation magnetic field signals according to the excitation signal sent from the excitation signal generating module the induction coils are for generating induced current signals according to the receive excitation magnetic field signal and the ambient magnetic field signal.

Abstract: An electronic magnetometer and a method for measuring a magnetic field are provided. A Gunn diode with magnetic shielding and a Gunn diode without magnetic shielding generate different induced high-frequency oscillating currents in various environments. The high-frequency oscillating current of the Gunn diode with magnetic shielding and the high-frequency oscillating current of the Gunn diode without magnetic shielding are processed by circuits and subsequently compared. The difference of frequencies in the two currents is proportional to the magnitude of magnetic field, and the magnitude of magnetic field is obtained.