Detection method and detection device for single nanoparticle

Abstract

The invention provides a single nanoparticle detection method and a single nanoparticle detection device. The single nanoparticle detection method comprises the following steps: exciting a surface plasmon standing wave, wherein the nanoparticles are placed in a surface plasmon standing wave field; acquiring a detection signal image; adjusting the position of a surface plasmon standing wave antinode; judging whether an interference image exists in each position of the detection signal image or not in the adjusting process; if yes, determining that the nanoparticles exists and acquiring an imageof the nanoparticles at the antinode position as a target signal image; and obtaining the size of the nanoparticles according to the target signal image and the refractive index of the nanoparticles.According to the technical scheme, the real-time detection of a single nanoparticle is realized based on interaction of a surface plasmon standing wave and the nanoparticle, local field distributioncan be enhanced, so that the scattered light intensity of the nanoparticle is increased, and the detection sensitivity is improved. The scattering intensity of the medium nano-particles with low refractive index and the sizes of the medium nano-particles form a linear relation, and the diameter of the minimum medium nano-particles which can be detected is half of the diameter of the minimum nano-particles detected by transmission surface plasmon polaritons.

Description

technical field [0001] The invention relates to the technical field of nano-detection, and more specifically, to a detection method and a detection device for a single nano-particle. Background technique [0002] Nanoparticles refer to tiny particles with a size ranging from 1 to 200 nanometers. According to the distribution characteristics, nanoparticles can be divided into two types: man-made particles and nano-pollutants. [0003] Among them, artificial particles refer to specially manufactured nano-sized particles, which have the characteristics of relatively uniform distribution, exist in designated positions, and are applied to many fields such as biomedicine, material science, and chemical industry; nano-particle pollutants refer to those that exist in nature , nano-scale particles harmful to human society, including nano-emissions and viruses. Nanoparticle pollutants widely exist in the natural environment and pose a huge hazard to human life, health and safety, so ...

AI Technical Summary

Problems solved by technology

[0004] However, it is very difficult to realize the detection of nano-pollutants. On the one hand, nanoparticles have the characteristics of extremely small size. Due to the limitation of diffraction order, ordinary optical microscopy imaging technology cannot detect particles of this scale, and high-sensitivity detection is required. On the other hand, compared with artificial nanomaterials, the size of nanoparticle pollutants is not uniformly distributed, and there is a big difference between particles. They exist in various carriers such as air and water at extremely low concentrations, and they Delays are changing, and nanoparticle contamination cannot be well characterized by tests that only capture particle collective properties

[0005] In the prior art, scanning electron microscopes, mass spectrometers and particle counters are used for detection. However, these methods take a long time to detect and require preprocessing, or the detection of individual particles cannot be achieved, or the detection accuracy is low and cannot be achieved. fulfil requirements

[0006] At present, the detection of single nanoparticles can also be realized by using resonant cavity sensing technology, nano-optical brazing to realize nanoparticle sensing and nano-slit technologies, but the cost is high and the detection environment is very high, which limits the Its scope of application

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