Experimental characterization of magneto-optical properties of Faraday crystal applied in magnetic field sensor
Eksperimentalna karakterizacija magneto-optičkih osobina Faradejevog kristala namenjenog za konstrukciju senzora magnetskog polja
Докторанд
Abudagel, Giuma Saleh IsaМентор
Petričević, SlobodanЧланови комисије
Stojković, ZlatanRomčević, Nebojša
Mihailović, Peđa
Barjaktarević, Marko
Метаподаци
Приказ свих података о дисертацијиСажетак
The thesis explores preparation and magneto properties of bismuth
germanium oxide single crystal (B12GeO20) which is irradiated by pulsed
femtosecond laser of increasing power. Analyses performed on irradiated and
un irradiated samples showed significant changes in transmittance, transmission
spectra, sample color, Raman spectra (RS), X-ray diffraction (XRD) pattern,
Verdet constant (VC), magneto-optical property and absorption coefficient. After
irradiation, the transmission spectra values increased whereas anisotropy
detected in the transmission spectra of unirradiated samples disappeared. The
change of color caused by irradiation was noticeable to the naked eye. The XRD
measurements confirmed structural changes induced by laser irradiation, i.e., the
laser- beam-incident side of the sample became almost amorphous, whereas the
side opposite to the incident can be indexed to the Bi12 Ge O20 compound.
Irradiation caused increase of Raman spectra peaks with the exception of crystal
peak...s of type E, which disappeared. The femtosecond pulsed laser irradiation
can be used to improve bismuth germanium oxide single crystal optical
properties. Femtosecond pulsed laser irradiation can improve optical properties
of Bi12 GeO20 single crystals.
Disertacija razmatra pripremu za proizvodnju i magneto optička
svojstva Bizmut germanijum oksidnih kristala (B12GeO20) koje se ozračuju
femtosekundnim laserskim impulsima zracima sa rastućom snagom. Analize
izvršene nad ozračenim i neozračenim uzorcima kristala pokazale su značajne
promene u transmitansi, transmisionom spektru, boji, Ramanovom spektru,
rezultatima difrakcije X zraka, Verdeovoj konstanti, magneto-optičkim
svojstvima i koeficijentu apsorpcije. Posle ozračivanja došlo je do porasta
transmitivnosti i izostanka anizotropije u transmisionom spektru u odnosu na
neozračene uzorke. Izmena boje uzoraka primetna je čak i golim okom. XRD
merenja pokazala su strukturne promene indukovane laserskim zracima tako da
je npr. strana uzorka neposredno ozračena laserom postala skoro potpuno
amorfna dok se suprotna strana uzorka indeksira na B12GeO20 jedinjenje.
Ozračivanje je izazvalo porast vrhova u Ramanovom spektru sa izuzetkom
vrhova za tip E koji se nisu pojavili. Femtosekundni laser...ski impulsi mogu se
iskoristiti da unaprede optička svojstva kristala...