CHAPTER 2
12
Odyssey Overview and General Description
Two solid state
diode lasers
simultaneously provide light excitation
at 685 and 785 nm.
Collimating lenses
,
optical
bandpass filters
, and
a
focusing lens
focus and tune the laser beams to produce an
excitation spot on the scanning surface. The microscope electronics
then modulate the laser beams to discriminate the infrared (IR) dye
signal fluorescence from background fluorescence. The scanner
detection optics
focus on the excitation spot and collect light from
the fluorescing IR dyes.
After collection by the
microscope objective
, the light is passed to a
dichroic mirror
. The mirror splits the light and essentially sorts the
fluorescent signals by transmitting the light above 810 nm and
reflecting light below 750 nm. Transmitted and reflected light travels
two independent paths through optics designed to remove scattered
and stray light. The light is ultimately focused onto one of two
avalanche photodiodes
that converts the light to an electrical signal
for processing by the microscope detection electronics.
In the microscope electronics, the signal is amplified, filtered, and
finally converted to a digital value by an analog-to-digital converter.
The digital signal is demodulated, filtered again, and coordinated
with the microscope position by a
Digital Signal Processor
(DSP) to
produce the image file.
The entire compact laser/microscope assembly travels on a platform
that moves beneath the scanning surface (below) along both the
X- and Y-axes.
Hardware Description
