Two solid-state
diode lasers (A) simultaneously provide excitation
at 680 and 780 nm. Both laser beams are focused
to form an excitation spot on the scanning surface.
The microscope objective (B) is focused on the
excitation spot and collects light from both
fluorescing infrared dyes. Resolution is user-adjustable
from 21 to 336 µm. Light from the microscope
objective is passed to a dichroic mirror (C)
that splits the light into two fluorescent signals
by transmitting light above 810 nm and reflecting
light below 750 nm. The transmitted and reflected
light travels two independent optical paths and
is finally focused on separate silicon avalanche
photodiodes (D) and detected. |