Selected Applications
attoCFM I
Resonant Spectroscopy on a Single Quantum Dot
Spectroscopy of semiconductor quantum dots (QDs) under resonant optical laser exci-
tation and of other single photon emitters, such as vacancy-centers often yields more
information about the emitters than more ubiquitous non-resonant excitation. However,
it is a technically challenging measurement to perform. The difficulty lies within the sep-
aration of the excitation laser photons from the re-emitted and scattered photons. One
way in which this can be achieved is by means of polarization suppression: in a geometry
where the scattered laser photons have a well-defined polarization, they can be filtered
from the detected signal facilitating the detection of resonance fluorescence (RF) of a
single quantum dot or any other quantum emitter.
The attoCFM I can be upgraded with a resonant fluorescence package (see left page),
which features an apochromatic performance that permits alignment free switching
between off resonant PL measurements and RF. This feature is fully enabled by our novel
cryogenic compatible apochromatic objectives designed to hold the focus plane at the
same position on the sample independently from the photon wavelength.
For the first this time combines the use of high precision rotators with the flexible beam
management confocal head attoCFM I. It provides extinction ratios of 10 7 ,
just a factor 10 away from the world record in research labs [1] while allowing an
unprecedented flexibility of use.
The top figure shows the resonance fluorescence of a quantum dot measured with the
attoCFM I equipped with the Polarization Extinction Option and a narrow band tunable
laser. In order to resolve the Mollow triplet, the emission is filtered through a high reso-
lution spectrometer. Here, the extinction ratio exceeds 10 6 , using the low temperature
near infrared apochromatic objective LT-APO\NIR.
The bottom figure shows the extinction ratio of the Polarization Extinction option for
the attoCFM I as a function of the rotation angle of the inbuilt piezo rotator equipped
with a quarter wave plate. In an angular region of 30 m° an extinction of more than 10 6
can be reached with a tunable narrow band diode laser (<1 pm line width).
[1] A.V. Kuhlmann et al., Review of Scientific Instruments 84, 073905 (2013).
(Measurement and data by E. Kammann 1 , S.H. E. Müller 1 , K. Puschkarsky 2 , M. Hauck 2 , S. Beavan 2 , A. Högele 2 , and K. Karrai 1 ,
1
attocube systems AG, Munich, Germany, 2 Ludwig Maximilian Universität, Munich, Germany)
attoMICROSCOPY
Sophisticated Tools for Science