attoPUBLICATIONS attoCATALOG-2017/18 | Page 134

PAGE 132 Upgrade Package: Polarization Extinction for resonant fluorescence excitation Using a technique called polarization extinction, one gains access to resonance fluorescence, which is of utmost importance in the study of semicon- ductor quantum dots, color centers in diamond, and novel materials of great interest such as silicon carbide and single molecules. The excitation laser is polarized such that it is reflected by a polarizing beam splitter (s) towards the sample. The back reflected light of the laser is then blocked by the same polarizing beam splitter and further sup- pressed, to obtain an extinction ratio of up to 10 7 with the attoCFM I. The fluorescence occuring at the same optical (i.e. resonant) wavelength, but different polarization (p) can be detected. For the purpose of alignment and calibration a rotatable quarter waveplate is mounted in the combined op- tical path down to the cold sample. Configuration Excitation channel rotatable polarizer* beamsplitter polarizing beamsplitter cube Detection channel rotatable polarizer* extinction ratio up to 10 7 depending on the laser (not included) Combined beam rotatable quarter waveplate* wavelength range(s) 480-550 nm, 500-600 nm, 565-770 nm, 700-1000 nm *closed loop rotation incl. electronics & software control