Apparatus and methods for particle testing
A particle testing apparatus, being configured for investigating particles in a fluid medium, includes a waveguide device having a hollow optical waveguide with an input end and an output end, an irradiation device including a laser source being arranged for optically trapping at least one particle at the input end of the optical waveguide and propelling the particle through the optical waveguide toward the output end thereof, and a measuring device being arranged for sensing the at least one particle in the optical waveguide, wherein the measuring device is arranged for measuring an optical transmission of the optical waveguide. Furthermore, a particle testing apparatus is described.
1. Particle testing apparatus, being configured for investigating particles in a fluid medium, comprising:
a waveguide device including a hollow optical waveguide having an input end and an output end,
an irradiation device including a laser source being arranged for optically trapping at least one particle at the input end of the optical waveguide and propelling the particle through the optical waveguide toward the output end thereof, wherein the laser source has high enough optical power to trap particles in front of the waveguide input end and then propel it along the hollow core of the waveguide,
a measuring device being arranged for sensing the at least one particle in the optical waveguide, and
an analysing device being coupled with the measuring device and being arranged for providing at least one particle feature, wherein
the laser source is arranged for focused irradiation of the input end of the optical waveguide from only one side thereof for optically trapping and propelling the at least one particle by the effect of radiation pressure of the laser light field and as a light source of the measuring device for measuring the optical transmission of the optical waveguide,
the measuring device is arranged for sensing the at least one particle in the optical waveguide by measuring an optical transmission of the optical waveguide along a longitudinal extension thereof,
the analysing device is adapted for providing the at least one particular feature based on an output of the measuring device and also on at least one of a duration, amplitude and waveform of particle induced changes of the measured optical transmission.
2. Particle testing apparatus according to claim 1 , further comprising
the analysing device is adapted for providing the at least one particle feature based on the optical transmission.
3. Particle testing apparatus according to claim 2 , comprising at least one of the features
the analysing device is adapted for providing at least one of a particle number, a particle size, a particle mass and a particle refractive index as the at least one particle feature, and
the analysing device is adapted for providing the at least one particle feature based on particle induced changes of the measured optical transmission.
4. Particle testing apparatus according to claim 1 , including at least one of the features
the irradiation device further comprises a first single mode fibre having an input end and an output end, wherein the input end of the first single mode fibre is coupled with an output of the laser source, and a first gradient index lens being arranged at the output end of the first single mode fibre for focusing laser light to the input end of the optical waveguide, and
the measuring device comprises a photodiode, a second single mode fibre having an input end and an output end, wherein the output end of the second single mode fibre is coupled with the photodiode, and a second gradient index lens being arranged at the input end of the second single mode fibre for collecting light from the output end of the optical waveguide.
5. Particle testing apparatus according to claim 1 , wherein the waveguide device further comprises
a casing containing the optical waveguide and having two transparent windows being arranged for coupling light from the laser source into the casing and light transmitted through the optical waveguide out of the casing, wherein
the casing is adapted for a flow through operation, wherein a supply section is arranged for supplying a particle containing sample into the casing and an exhaust section is arranged for guiding the sample out of the casing.
6. Particle testing apparatus according to claim 1 , wherein
the optical waveguide is a hollow core photonic crystal fibre.
7. Particle testing method for investigating particles in a fluid medium, comprising:
providing a sample including at least one particle at a hollow optical waveguide having an input end and an output end;
optically trapping the at least one particle at the input end of the optical waveguide and propelling the particle through the optical waveguide toward the output end with a laser source of an irradiation device, the laser source being used for e tically rapping of the at least one particle and illuminating the optical uide for measuring the optical transmission ereof wherein the laser source provides focused irradiation of the input end of the optical wave guide om only one side thereof for optically trapping and propelling the at least one particle by the effect of radiation pressure of the laser light field and provides a light source of the measuring device for measuring the opt cal transmission of the optic reguide, and the laser source has high enough optical power to trap particles in front of the waveguide input end and then propel it along the hollow core of the waveguide; and
sensing the at least one particle in the optical waveguide with a measuring device, wherein
the measuring device senses the at least one particle in the optical waveguide by measuring an optical transmission of the optical waveguide along a longitudinal extension thereof, and
at least one particle feature is provided by analysing an output of the measuring device, the at least one particle feature being provided based on at least one of a duration, amplitude and waveform of particle induced changes of the measured optical transmission.
8. Particle testing method according to claim 7 , including providing the at least one particle feature including at least one of a particle number, a particle size, a particle mass and a particle refractive index as the at least one particle feature.
9. Particle testing method according to claim 8 , including the step of
providing the at least one particle feature based on particle induced changes of the measured optical transmission.
10. Particle testing method according to claim 7 , including at least one of the features
the optically trapping of the at least one particle is obtained by illuminating the input end of the optical waveguide by the laser source via a first single mode fibre and a first gradient index lens, and
sensing the at least one particle in the optical waveguide is obtained by directing light transmitted through the optical waveguide through a second gradient index lens and a second single mode fibre to a photodiode.
11. Particle testing method according to claim 7 , comprising the step of
arranging the optical waveguide in a casing having two transparent windows for coupling light from the laser source into the casing and light transmitted through the optical waveguide out of the casing, wherein
the casing is adapted for a flow through operation.
12. Particle testing method according to claim 7 , wherein the sample is provided for at least one of
monitoring environmental air or water pollution,
monitoring gases or vapors or liquids emitted from at least one of machines and vehicles, and
monitoring at least one of type and size of dust in an environment.