Fluorescence excitation and detection system and method

A detection system for detecting different wavelengths of emission light emitted from a sample, the system comprising:

• a detection assembly to receive the emission light emitted from the sample, the detection assembly including a multi-band dichroic member and at least first and second detection devices, the multi-band dichroic member having a transmission and reflection characteristic with at least two transmissive regions separated from each other along a wavelength spectrum and with at least one reflective region separated from the transmissive regions along the wavelength spectrum, the dichroic member transmitting portions of the emission light that align with the at least two transmissive regions, the dichroic member reflecting a portion of the emission light that aligns with the reflective region;
• wherein the at least two transmissive regions include first and second transmissive regions and the at least one reflective region includes first and second reflective regions, and wherein the dichroic member comprises a single dichroic mirror having an incident surface with the transmission and reflection characteristic comprising the first and second transmissive regions and the first and second reflective regions, the first transmissive region passing and the first reflective region reflecting corresponding portions of the emission light that are emitted in response to a first excitation wavelength, the second transmissive region passing and the second reflective region reflecting corresponding portions of the emission light that are emitted in response to a second excitation wavelength, wherein the corresponding portions of the emission light emitted in response to the first and second excitation wavelengths are passed or reflected at a common active area of the incident surface.