Method and instrumentation for determining a physical property of a particle

摘要

Physical property determination of a particle or classification of the particle as a function of the physical property by evaluating scattered light profile from a single particle is disclosed. The particle may include chemical structures that vibrate as a function of a physical property of the particle. The physical property may include an absorptive property of the particle or a chemical composition. From a detected scattered light spectrum, at least two anomalous dispersive regions may be identified. The physical property of the particle may be determined as a function of the at least two regions. A system employing the physical property determination can achieve sensitivities useful for low particle density applications such as detection for biological and chemical agents.

主权项

1. A method of determining a physical property of a particle, the method comprising:
illuminating a particle with infrared light; detecting elastically scattered light from the particle having a size smaller than or equal to the wavelength of the scattered light, having chemical structures, to determine an elastic scattering spectrum of the particle; identifying at least two regions of the elastic scattering spectrum of the particle representative of vibrations of the chemical structures by identifying regions of non-decrease of intensity of scattered light in regions of the spectrum of increasingly longer wavelengths; determining an absorption spectrum of the particle based on the at least two regions of the elastic scattering spectrum of the particle, the absorption spectrum defined by respective absorption peaks spectrally located within respective regions of the at least two regions of the elastic scattering spectrum, and the respective absorption peaks corresponding to respective peaks in an imaginary part of a refractive index of the particle; and determining the physical property of the particle based on the absorption spectrum of the particle based on the at least two regions of the elastic scattering spectrum.