Experiments to Control Atom Number and Phase-Space Density in ...
Experiments to Control Atom Number and Phase-Space Density in ...
Experiments to Control Atom Number and Phase-Space Density in ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Feshbach coil<br />
objective lenses<br />
a<strong>to</strong>ms<br />
reentrant viewport<br />
vacuum chamber<br />
Figure 7.39: Future vertical axis optics. The Nd:YAG tweezer beam will be focused<br />
through the objective lens un<strong>to</strong> the a<strong>to</strong>ms. The MOT beam will come from the bot<strong>to</strong>m<br />
<strong>and</strong> be retroreflected above the vacuum chamber with the help of additional optics. The<br />
objective will also be used <strong>to</strong> collect the fluorescence signal for s<strong>in</strong>gle-a<strong>to</strong>m detection.<br />
In pr<strong>in</strong>ciple aspheric lenses are designed <strong>to</strong> m<strong>in</strong>imize aberrations <strong>to</strong> generate the<br />
smallest spot size possible. However, these lenses are not designed hav<strong>in</strong>g the glass of<br />
the vacuum viewport <strong>in</strong> m<strong>in</strong>d. The meniscus lens is therefore added <strong>to</strong> compensate for<br />
the effect of that w<strong>in</strong>dow.<br />
The objective will also be used <strong>to</strong> collect the fluorescence light for s<strong>in</strong>gle-a<strong>to</strong>m<br />
detection. A large numerical aperture of the objective is therefore important <strong>and</strong> the<br />
diameter of the objective lenses should be kept as large as possible. With this objective<br />
it is expected <strong>to</strong> collect about 10% of the scattered pho<strong>to</strong>ns. These pho<strong>to</strong>ns can then<br />
be spatially filtered <strong>and</strong> focused on<strong>to</strong> the avalanche pho<strong>to</strong> diode (APD, Perk<strong>in</strong> Elmer,<br />
SPCM-AQR-14) for s<strong>in</strong>gle-a<strong>to</strong>m detection. A dichroic mirror comb<strong>in</strong>es the YAG beam<br />
<strong>and</strong> the scattered pho<strong>to</strong>n beam paths.<br />
The MOT beam will be focused by the objective lens. Additional lenses can<br />
recollimate the beam, before it is retro-reflected. An optical layout of the envisioned<br />
optical setup is shown <strong>in</strong> figure 7.40. A mirror required for the MOT load<strong>in</strong>g stage can<br />
be moved away after the MOT is loaded.<br />
134