Description
In a cold-atom experiment with an optical tweezers array, a laser beam with a designed wavefront is focused through a high numerical-aperture objective lens to form an arbitrarily shaped light pattern on the focal plane in a vacuum chamber [1, 2, 3]. Accordingly, the pattern is often deteriorated by aberrations in optical components and thereby should be monitored and evaluated in situ. However, it is difficult to do so due to the difficulty of accessing the focal plane in a vacuum chamber.
We will report on an “atom camera” method that we have developed for imaging the light pattern with a single $^{87}$Rb atom in an optical tweezers. We sense the intensity and polarization profiles of a light pattern at the atom position that manifest themselves in the light shift of the hyperfine transition. By scanning the atom position in steps of sub-micrometers, we reconstruct high-resolution 2D images of the intensity and polarization. The resolution is limited only by the uncertainty of the atom position, which is reduced down to the level of quantum fluctuations (~ 30 nm) by cooling the atom to the motional ground state of the tweezers [3], thus far better than the diffraction limit at optical wavelengths. This technique serves as an important tool for the design and evaluation of submicron-scale light patterns.
[1] A.Browaeys and T. Lahaye, Nat. Phys. 16, 132-142 (2020).
[2] F. Nogrette et al., PRX 4, 021034 (2014).
[3] Y. Chew et al., arXiv: 2111.12314.
| Presenter name | Takafumi Tomita |
|---|---|
| How will you attend ICAP-27? | I am planning on in-person attendance |
