This document discusses Fourier transform infrared (FTIR) spectroscopy. It begins by introducing terahertz radiation and its applications in cancer detection and security imaging. It then explains how FTIR spectroscopy works, using an interferometer to generate a beam containing many frequencies that is passed through a sample, with the absorption measured. Computer processing via the Fourier transform is required to convert the raw data into the desired absorption spectrum. FTIR spectroscopy has the advantage over scanning spectroscopy of being faster. The document concludes by noting potential applications and advantages of FTIR spectroscopy.

1. Fourier transform infrared
spectroscopy
Berezin Danila

2. Plan of a journey
Terahertz radiation
Its application
And research
FTIR spectroscopy

3. Terahertz radiation is an electromagnetic waves
Terahertz gap
1011 – 1013 Hz

4. THz technology brings better sensing capabilities
cancer
cavity
Visible image THz image

5. THz technology brings better sensing capabilities
Visible image THz image
ceramic
knife

7. The goal is to measure how well a sample absorbs light
sample light

8. Scanning spectroscopy is the most straightforward way
goal – spectrum
of absorption

9. beam source sample detector
absorption
It shines a monochromatic light beam…

10. beam source sample detector
absorption
…and measures how much is absorbed

11. FT spectroscopy is a less intuitive way to obtain the
same information
goal – spectrum
of absorption

12. beam source sample detector
absorption
beam number
A beam contains many frequencies of light at
once and absorption of that beam is measured

13. beam source sample detector
absorption
beam number
Next, beam is modified to give a second data point

14. beam source sample detector
absorption
beam number
Process is repeated many times

15. Afterwards, computer processing is required

16. There are still undiscovered nuances
How to generate and modify that
special beam?
What computer processing is
required?

17. moving mirror
Wave interference is a key to generate that special beam
Michelson interferometer
light source
beam for the
experiment

18. Processing required is Fourier transform
raw data desired result

19. FT spectroscopy has an advantage – Fellgett’s advantage
Scanning
spectroscopy
Fourier transform
spectroscopy

20. FTIR spectroscopy
– Possible applications
– Technology
– Advantage

21. Thank you

22. Back up

23. Fourier transform
mirror 1
mirror 2
y1/2
x/2
Monochromatic source

24. Polychromatic source
Fourier transform

25. Fourier transform