Diode pumped intracavity laser particle counter with improved reliability and reduced noise
AssigneeParticle Measuring Systems, Inc.
InventorsDwight A. Sehler, Todd A. Cerni
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Abstract
A fluid particle counter comprising an intracavity diode pumped solid state laser having a solid state lasing material having a non-reflective coating and a concave mirror having a reflective coating, with the coatings isolated from the sample flow by Brewster windows. The laser beam is apertured by an aperture assembly including an inner aperture closest to the inlet nozzle assembly and an outer aperture farther from the inlet nozzle assembly, with the outer aperture significantly farther from the inner aperture than the inner aperture is from the inlet nozzle assembly.
Claims18
A device for optically detecting an unconstrained particle suspended in a flowing fluid, said device comprising:
- a diode pumped solid state laser (DPSSL) including a basing medium and a concave mirror defining a laser cavity, said lasing medium and concave mirror each having an optical coating on the end closest the other;
- an inlet nozzle assembly located between said lasing medium and said concave mirror;
- and
- a Brewster window located either between said optical coating on said lasing medium and said inlet nozzle assembly or between said optical coating on said concave mirror and said inlet nozzle assembly.
A device for optically detecting an unconstrained particle suspended in a flowing fluid, said device comprising:
- a diode pumped solid state laser (DPSSL) having a laser cavity;
- an inlet nozzle assembly providing fluid sample flow within said laser cavity;
- and
- an aperture assembly comprising no more than two apertures, including an inner aperture plate having an inner aperture and an outer aperture plate having an outer aperture farther from said inlet nozzle assembly than said inner aperture;
- and
- wherein said outer aperture is at least four times further from said inner aperture than said inner aperture is from said inlet nozzle assembly.
A method for optically detecting an unconstrained particle suspended in a flowing fluid, said method comprising:
- providing a diode pumped solid state laser (DPSSL) including a lasing medium and a concave mirror defining a laser cavity, said lasing medium having an optical on an end facing said concave mirror and said concave mirror having an optical coating an end facing said lasing medium;
- directing a sample fluid flow into said laser cavity between said lasing medium and said concave mirror;
- and
- sealing said optical coatings from said sample flow.
Dependencies are inferred from the claim text.