Flow cytometers including light collection enhancers, and methods of using the same

A method of analyzing a sample, the method comprising:

• (a) introducing the sample into a flow cytometer comprising:
• a flow cell for transporting particles in a flow stream;
• a light source for irradiating the particles in the flow stream at an interrogation point;
• an objective lens for focusing particle-modulated light propagating within a first light collection cone;
• and
• a light collection enhancer configured to collect particle-modulated light propagating along an optical path within a second light collection cone and redirect the collected light such that it is back-propagated along the same optical path and focused by the objective lens;
• and
• (b) flow cytometrically analyzing the sample.

A method of assembling a flow cytometer, the method comprising:

• (a) positioning a light collection enhancer within a flow cytometer, wherein:
• the flow cytometer comprises:
• a flow cell for transporting particles in a flow stream;
• a light source for irradiating the particles in the flow stream at an interrogation point;
• and
• an objective lens for focusing particle-modulated light propagating within a first light collection cone;
• and
• a light collection enhancer configured to collect particle-modulated light propagating along an optical path within a second light collection cone and redirect the collected light such that it is back-propagated along the same optical path and focused by the objective lens;
• and
• (b) optically aligning the light collection enhancer with the objective lens to assemble the flow cytometer.