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This is a background presentation for my speech about Fourier transform infrared spectroscopy.
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Fourier transform infrared spectroscopy
Berezin Danila
Plan of a journey
Terahertz radiation
Its application
And research
FTIR spectroscopy
Terahertz radiation is an electromagnetic waves
Terahertz gap1011 – 1013 Hz
THz technology brings better sensing capabilities
cancer
cavity
Visible image THz image
THz technology brings better sensing capabilities
Visible image THz image
ceramicknife
The goal is to measure how well a sample absorbs light
sample light
Scanning spectroscopy is the most straightforward way
goal – spectrumof absorption
beam source sample detector
abso
rptio
n
It shines a monochromatic light beam…
beam source sample detector
abso
rptio
n
…and measures how much is absorbed
FT spectroscopy is a less intuitive way to obtain the same information
goal – spectrumof absorption
beam source sample detector
abso
rptio
n
beam number
A beam contains many frequencies of light atonce and absorption of that beam is measured
beam source sample detector
abso
rptio
n
beam number
Next, beam is modified to give a second data point
beam source sample detector
abso
rptio
n
beam number
Process is repeated many times
Afterwards, computer processing is required
There are still undiscovered nuances
How to generate and modify that special beam?
What computer processing is required?
moving mirror
Wave interference is a key to generate that special beam
Michelson interferometer
light source
beam for theexperiment
Processing required is Fourier transform
raw data desired result
FT spectroscopy has an advantage – Fellgett’s advantage
Scanningspectroscopy
Fourier transformspectroscopy
FTIR spectroscopy
– Possible applications– Technology– Advantage
Thank you
Back up
Fourier transformmirror 1
mirror 2
y1/2x/2
Monochromatic source
Polychromatic source
Fourier transform
Fourier transform