What is the role of dichroic filters positioned at a 45-degree angle in a flow cytometer?

The role of dichroic filters positioned at a 45-degree angle in a flow cytometer is to transmit short wavelengths of light while reflecting longer wavelengths. This is crucial in the flow cytometry process, as it enables the separation of different fluorescent signals emitted by various dye markers attached to the cells being analyzed.

When light passes through a dichroic filter at this specific angle, it can be selectively directed towards the detector corresponding to the emitted fluorescence of a certain wavelength while blocking out longer wavelengths. This property is essential for ensuring that the detection system can accurately measure the fluorescence from multiple markers without interference from unwanted wavelengths.

By effectively managing the light paths, the dichroic filter plays a critical role in the overall sensitivity and specificity of the flow cytometry analysis, allowing for the identification and quantification of specific cell populations based on their fluorescent characteristics.