Optical detection systems and methods of using the same
Optical detection systems configured to collect and detect light emitted by a sample are provided. Aspects of the systems include a core region selective side scatter (SSC) collection module configured to allow for the selective detection SSC wavelength light from a core region of collected light. Also provided are methods of using the systems.
1. An optical detection system comprising:
a light collection system comprising an objective lens and configured to produce objective lens imaged collected light from a detection zone of a flow cell, wherein the objective lens imaged collected light is light collected and focused by the objective lens;
a light disperser configured to separate the objective lens imaged collected light into at least two wavelengths of light;
a first detector configured to detect a first of the at least two wavelengths of light and a second detector configured to detect a second of the at least two wavelengths of light, wherein the first wavelength of light is a side scatter (SSC) wavelength light; and
an aperture comprising an optical mask configured to selectively block SSC wavelength light from the objective lens imaged collected light that is outside of an innermost core region from reaching the first detector, wherein the aperture has a size that is matched to the innermost core region.
2. The optical detection system according to claim 1 , wherein the aperture has a diameter ranging from 50μ to 500μ.
3. The optical detection system according to claim 1 , wherein the optical mask does not block passage of at least one non-side scatter wavelength light.
4. The optical detection system according to claim 1 , further comprising a fiber optic light conveyer positioned between the aperture and the light disperser, wherein the fiber optic light conveyor is configured to convey objective lens imaged collected light that has passed through the aperture to the light disperser.
5. The optical detection system according to claim 4 , wherein each of the first and second detectors comprise a photodiode based light detector or a photomultiplier tube (PMT).
6. The optical detection system according to claim 5 , wherein the fiber optic light conveyor comprises a core that has a diameter that is larger than the innermost core region.
7. A method of analyzing a flow stream, the method comprising:
irradiating a flow stream with a light source;
generating objective lens imaged light collected from a detection zone of the irradiated flow stream, wherein the objective lens imaged collected light is light collected and focused by the objective lens; and
passing the objective lens imaged collected light through an aperture to a light disperser, wherein:
(i) the aperture comprises an optical mask that selectively blocks side scatter (SSC) wavelength light outside of an innermost core region from passing through, wherein the aperture has a size that is matched to the innermost core region; and
(ii) the light disperser is configured to separate the objective lens imaged collected light into at least a first and a second wavelength of light, wherein the first wavelength of light is SSC wavelength light; and
detecting the first and second wavelengths of light to analyze the flow stream.