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 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: 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.