A desktop Faraday rotation instrument in the ultraviolet
2008 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 79, no 2Article in journal (Refereed) Published
A simple versatile desktop instrument for the measurement of Faraday rotation in the ultraviolet range has been designed and constructed. A high pressure short arc mercury lamp is used for the light source. By using interference filter for mercury, the desired wavelength of the available lines for mercury (e.g., 365, 405, and 436 nm) is selected. Our instrument measures hysteresis loops in magnetic fields up to 900 kA/m within a few minutes. With a light beam intensity monitor, the detrimental effect from fluctuations in the light source has been virtually eliminated. The instrument can operate at photocurrents from the picoampere regime and above with a Faraday rotation sensitivity of around 1 millideg. By incorporating a higher order Taylor expansion approach, we improve the linearity of the Faraday rotation to transmitted light relationship by two orders of magnitude. The electronics is custom designed analog type, rendering relaxed dynamic requirements for the analog-to-digital converter. The design is fully protected from ambient light which makes operation with the equipment in darkness superfluous; neither does it need any optical table. The data acquisition and operation of the instrument are fully supported by a LABVIEW program. Measurements on a magnetite thin film and on microscope cover glass are given as examples for the performance and sensitivity of the equipment.
Place, publisher, year, edition, pages
2008. Vol. 79, no 2
room-temperature, magnetite fe3o4
IdentifiersURN: urn:nbn:se:kth:diva-17393DOI: 10.1063/1.2868789ISI: 000254194400056ScopusID: 2-s2.0-40149086046OAI: oai:DiVA.org:kth-17393DiVA: diva2:335437
QC 201005252010-08-052010-08-05Bibliographically approved