attoCFM I+
PAGE 46
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 semiconductor 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 suppressed, to obtain an extinction ratio of up to 107
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 optical path down to the cold sample.
Configuration
Excitation channel
rotatable polarizer*
Beamsplitter
polarizing beamsplitter cube
Detection channel
rotatable polarizer*
Extinction ratio
Up to 107 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