Particle characterisation in open optical resonator cavity

#This application is a national phase of International Application No. PCT/GB2017/051427 filed May 22, 2017, and claims priority to Great Britain Application No. 1609017.7 filed on May 23, 2016, which is incorporated herein by reference.

#The present invention relates to characterisation of particles.

#The ability to achieve label-free characterisation of particles, which may be nanoparticles, in solution is important for a wide range of industrial and scientific applications. Fields as diverse as healthcare, materials science, environmental science, and security all involve the detection and identification of particles. Techniques capable of identifying nanoparticles between 30 nm and 300 nm in size at very low concentrations are particularly useful in the life sciences and security applications, since viruses and particles such as exosomes (which are key actors in the transport of genetic information) are typically to be found in this size range. Methodologies that allow characterisation of multiple properties at the single particle level are particularly valuable for real-time monitoring and identification of particles without prior knowledge of the contents of the fluid sample.

#To allow better understanding, embodiments of the present invention will now be described by way of non-limitative example with reference to the accompanying drawings, in which:

#FIG. 1 is a cross-sectional view of an open optical cavity;

#FIG. 2 is a schematic perspective view of an extended open optical cavity;

#In the methods described herein, the light used may be: ultraviolet light (which may be defined herein as having wavelengths in the range from 10 nm to 380 nm); visible light (which may be defined herein as having wavelengths in the range from 380 nm to 740 nm); infrared light (which may be defined herein as having wavelengths in the range from 740 nm to 300 μm). The light may be a mixture of wavelengths. Herein, the terms ‘optical’ and ‘optics’ are used to refer generally to the light to which the methods are applied.

#In the methods described herein, the particle may be of the following types.

#The methods described herein may be applied to any type of polarizable particle of interest. In principle, any particle that is polarizable will affect the resonance and so provide a response, although the degree of polarizability may affect the size of the response.