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## Development of white light interferometer with LED illumination

### Mikołaj Rogalski

#### Abstract

The aim of this thesis was to develop the white light interferometer with LED illumination and minimal scanning step not lower than 0.05 µm. Theoretical part of the thesis begins with the short introduction (chapter 1.) that explains the reason of engaging in this project and explains the problem. In the next chapter (chapter 2.) there the basics of the white light interferometry are discussed. There are also shown the fundamental formulas that shows the difference between monochrome interference and white light interference along with the graphs of the fringes intensity layout as a function of OPD for different light sources. Chapter 3. shows three most popular white light interferometers and presents the principle of operation of the fringe analysis methods along with the list of this methods. This chapter also presents the currently used commercial profilometers that makes use of white light interferometry. Theoretical part of this thesis ends with description of the main white light interferometry applications (chapter 4.). Practical part of the thesis describes built laboratory interferometer (chapter 5). The used LED is described along with its spectral character and its graphs of the fringes intensity layout as a function of OPD. The obtained results are compared with the theoretical values of the different diodes. In this chapter there are also described used camera, used optical elements (mirror, beam splitter and lens) and used highresolution stepper-mike actuator. At the end of this chapter the finished interferometer along with its parameters is shown. In the chapter 6 it is described the process of aligning the system. Chapter 7 describes the handling of the system and the process of making a measurement. In the next chapter (chapter 8) it is explained why it is impossible to use commonly used fringes analysing methods with such a big scanning step. Further step-by-step description of a self-prepared fringes analysing algorithm that is able to overcome the big scanning step problem is done. In the chapter 9 there are the results of the measurements with built interferometer shown. The measurements were made for the different light sources (single red, green or blue diode, pairs of this diodes and the all three diodes lightning simultaneously) and for the different steps of the stepper-mike actuator. The results are compared with the results obtained on the commercial profilometer. Chapter 10 contains the conclusions of the thesis, what has been achieved and what in the built interferometer can be still improved.
Diploma type
Engineer's / Bachelor of Science
Diploma type
Engineer's thesis
Author
Mikołaj Rogalski (FM) Mikołaj Rogalski,, Faculty of Mechatronics (FM)
Title in Polish
Opracowanie koncepcji interferometru światła białego z oświetleniem diodowym LED
Supervisor
Anna Pakuła (FM/IMPh) Anna Pakuła,, The Institute of Micromechanics and Photonics (FM/IMPh)Faculty of Mechatronics (FM)
Certifying unit
Faculty of Mechatronics (FM)
Affiliation unit
The Institute of Micromechanics and Photonics (FM/IMPh)
Study subject / specialization
, Mechatronika
Language
(pl) Polish
Status
Finished
Defense Date
07-02-2019
Issue date (year)
2019
Reviewers
Anna Pakuła (FM/IMPh) Anna Pakuła,, The Institute of Micromechanics and Photonics (FM/IMPh)Faculty of Mechatronics (FM) Wojciech Krauze (FM/IMPh) Wojciech Krauze,, The Institute of Micromechanics and Photonics (FM/IMPh)Faculty of Mechatronics (FM)
Keywords in Polish
interferometria światła białego, profilometria optyczna, LED
Keywords in English
white light interferometry, optical profilometry, LED
Abstract in Polish
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Identyfikator pracy APD: 31810

Uniform Resource Identifier
https://repo.pw.edu.pl/info/bachelor/WUT618ea0f432454620bf104f9e16aa8786/
URN
urn:pw-repo:WUT618ea0f432454620bf104f9e16aa8786

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