Optical design of real-time fluorescence measurement for qPCR.

<p>The blue LED (470 nm) emits excitation wavelength that is filtered through an excitation filter which is a band-pass filter of 455 to 495 nm. The excitation light travels through the hole in the aluminum rod and is absorbed to the sample in the PCR tube. The emitted light is collected by an avalanche photodiode through an emission filter, with a band-pass at 511 to 529 nm.