Schematic view of the optical system. A laser beam emitted from the laser head is used as an excitation light source. The laser beam is guided to a scanning objective lens through a tunnel mirror and is focused on capillary array. The fluorescent light from the dye combined with a reaction product is collected with the objective lens and is passed through a cut-off rejection filter to eliminate laser scattering light. The collected fluorescent light is focused and passed through an alias to cut off a defocusing rays. Four convex lens divide the ray four. Each ray passes through a different band-pass filter and is detected with a photo multiplier. These optical and detection devices without a laser head are scanned during data taking time.
