Even if the atoms are all confined into the vacuum chamber, we need a full table of optical elements to prepare and control the quantum properties of the atoms.
We prepare, control and measure the atoms inside the vacuum chamber with light.
We need a lot of different light beams to work with the atoms: some are used to trap the atoms, some to prepare the atoms in the desired state, some to measure their final state.
All the optical elements on the table (lenses, mirrors, wave plates, etc.) control and prepare the light, so that it can interact correctly with the atoms.
The table is filled with holes, so we can easily screw the optical elements in different positions to change from one experiment to another one.
The table is floating on its legs to insulate it from the vibrations of the ground: quantum states are very delicate and we have to insulate them from the environment.
An optical fiber is a flexible, transparent fiber made by glass or plastic with a diameter slightly thicker than that of a human hair. Optical fibers are used to efficiently transmit light with minimal loss and avoiding any potential electromagnetic interference.
All the blue and yellow cables around the lab are optical fibers.
We use optical fibers to bring light from one side to the other of the lab to connect all the different parts of the experiment.
This chamber holds cold atoms, which can work as the microscopic elements of quantum technologies.
We have to be sure that in the chamber there are only the atoms we are interested in, without impurities: that's why we extracted all the air that was inside, creating vacuum inside.
This is one of the coldest corners of the planet: only a small fraction of the absolute zero (micro- or nano- Kelvin).
There is no fridge that can get as cold as that: we need powerful lasers and magnetic fields to cool down and trap the atoms.
There is no thermometer able to measure such low temperatures: at these levels, we have to estimate the temperature by observing with a camera how fast the atom cloud expands.
You can't touch the atoms, but you can use light to change or measure their state.
The atoms are the core of the experiment, but we need all the other elements of the lab to control them.
Here we have Rubidium atoms, but also many other elements of the first two columns of the periodic table (Potassium, Strontium, etc.) are used in cold atoms experiments. Scientists choose these because they have simpler electronic structures, i.e. it's as if they have only one or two electrons.
Atoms do not interact with any kind of light: given a certain element, only very specific light wavelengths can interact with it.
In this lab we look at the quantum properties of atoms through light, but it won't be possible without a lot of classical electronics.
We use all sort of electronics (power supplies, amplifiers, filters, etc.) to control and drive all the lasers and scientific instruments around the lab.
All the grey and black cables you see are electronic cables connecting the devices around the lab.
Laser light is the basic ingredient of many quantum (and not only quantum) experiments.
In these boxes we have the different lasers we need to operate the experiment, plus the optical elements that we need to couple the light into the optical fiber.
The optical fiber brings the laser light to the other optical table.
We have to choose and stabilise very carefully the wavelength of our lasers, so that they can interact with the atoms.
This setup generates pairs of entangled photons: this means that this two photons are so interconnected that they can’t be described as two separate elements and that a measurement over one of them will affect inevitably the state of the other one.
Thanks to the crystal inside the white cylinder, we can generate entangled photon pairs, that are the basic ingredient of many quantum technologies.
A powerful laser goes through the crystal: some of the photons split into two so that the sum of the energies of the two new photons equals the energy of the original one. The polarization of the two photon is entangled, too.