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Optical Cavity Ring-down Spectroscopy
Detection System |
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Optical cavity ring-down spectroscopy
technology is an emerging method of spectrum
detection. This technology is especially
suitable for substance weak absorption with its
characteristics of long absorption optical path
and unaffected by the light intensity
fluctuation. It is applied to the accurate
measurement of high reflectivity of lens
(accuracy up to 10-4 ～10-6) and trace gas
detection with features of simple device and
easy quantitative measurement.
In CNI
Optical Cavity Ring-down Spectroscopy Detection
System, as follow figure shows, pulsed laser as a
laser source, optical resonant cavity composed
of high reflectivity lens M1 and M2, the laser
pulse is reflected back and forth between the
two mirrors to from oscillation when pulsed
laser along with the optical axis injected into
the cavity. Laser pulse ring-down process and
time is detected and recorded by the photodetector behind M2. Then the cavity gas
concentration can be calculated In the condition
of known cavity mirror reflectivity. |
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Specifications |
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Short pulse laser |
Pulse duration: 5-20ns,
repetition rate:<10KHz,
output power: 0-100mW. |
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High speed photodetector |
Si substrate photodetector,
rise time: 1ns, spectral
response range: 400-1100nm |
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Ring-down cavity |
Cavity length: 600mm
(customized), cavity mirror
reflectivity>99.92%@ center
wavelength |
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Others |
Oscilloscope, air chamber |
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Detection
Signal |
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600mm
straight ring-down spectroscopy
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Application case |
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Beijing Jiaotong University School of
Science uses CNI optical ring-down
spectrum detection system for visibility
detection experiments. |
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