Patent ID: 8101426

Claim:
A flow cytometer for measuring fluorescent emission from a particle, the flow cytometer comprising: a first excitation light source producing a first modulated excitation beam modulated at a first frequency; a second excitation light source producing a second modulated excitation beam modulated at a second frequency, said second frequency being different than said first frequency; beam combining optics adapted to receive said first and second modulated excitation beams and produce a combined modulated excitation beam; a single detector adapted to measure fluorescent emission from said particle when said particle is within said combined modulated excitation beam, said single detector producing a single detector output signal; and a signal processor operatively coupled to said single detector for receipt of said single detector output signal, said signal processor operative to use said first frequency and said second frequency to distinguish a first portion of said single detector output signal caused by excitation of said particle by said first modulated excitation beam and a second portion of said single detector output signal caused by excitation of said particle by said second modulated excitation beam even when said first portion and said second portion overlap temporally.