ATTO
3
Manual 1.6
11
Spectroscopy Introduction
What is spectroscopy?
Spectroscopy
in its broadest sense is the study of the interaction between matter
and electromagnetic radiation. Spectroscopy involves separating light into its
constituent wavelengths and reading out the intensity distribution versus
wavelength. Different methodologies of spectroscopy provide information of the
sample based on its interaction with electromagnetic radiation. Measurement of
scattering, reflection of incident radiation from a surface/sample provides its
scattering properties. One can also measure the transmission of electromagnetic
radiation and estimate its absorbance that unravels the molecular fingerprints of the
constituents of the sample be it solid, liquid or gas.
Reflectance, Transmittance & Absorbance
The reflectance (
R(λ)
) of an object is measured as follows:
•
Measure Dark Spectrum(optional)
•
Measure the spectrum of the illuminant also known as bright spectrum (
B(λ)
)
•
Optionally subtract the dark spectrum (
D(λ)
)
•
Divide the measured spectrum (
S(λ)
) by the bright spectrum (
B(λ)
)
𝑅(𝜆) =
𝑆(𝜆) − 𝐷(𝜆)
𝐵(𝜆) − 𝐷(𝜆)
The transmittance (
T(λ)
) of an object is measured as follows:
•
Measure Dark Spectrum(optional)
•
Measure the spectrum of the illuminant also known as bright spectrum (
B(λ)
)
•
Optionally subtract the dark spectrum (
D(λ)
)
•
Divide the measured spectrum (
S(λ)
) by the bright spectrum (
B(λ)
)
𝑇(𝜆) =
𝑆(𝜆) − 𝐷(𝜆)
𝐵(𝜆) − 𝐷(𝜆)
Absorbance is typically derived as follows:
𝐴(𝜆) = 1 − 𝑇(𝜆) − 𝑅(𝜆)
Summary of Contents for ATTO3
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