Vacuum Optics ❯ Magneto-optical traps
Magneto-optical traps
What are magneto-optical traps?
Torr Scientific offers a range of magneto-optical traps (MOT) (also known as atom trap chambers) used as part of ultra-cold vacuum systems, to capture atoms for testing purposes.
This is a chamber module, formed of low-magnetic permeability materials for use at ultra-low temperatures nearing absolute zero (~50 nanokelvin).
The process of “trapping atoms” opens the doors for research in physics, chemistry and even meteorology. This is a unique method for researching quantum electrodynamics, creating gravimeters, atomic clocks and even has potential within quantum computing, which could have widescale impacts across physics.
To enquire about magneto-optical traps, please reach out to our sales team.
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How do magneto-optical traps work?
Atom trap chambers use photons and magnetic fields to reduce the velocity of atoms moving towards the lasers, trapping them in place.
Atom trap chambers use photons and magnetic fields to reduce the velocity of atoms moving towards the lasers, trapping them in place.
The atomic resonance frequency is defined as the rate of an atom’s emission and absorption of light.
Due to the Doppler effect, as atoms move towards the lasers, the emitted wavelengths are compressed. This means the emission rate is shifted closer to the atomic resonance frequency.
The impact of this is that the atoms absorb more light when moving towards the laser. This causes them to slow down, a technique called “optical molasses” humorously named after the treacle-like slowing of atoms.
To avoid the atoms moving away from the lasers, another phenomenon is utilised called the Zeeman shift. This splits the atoms’ “atomic energy levels”, which causes the atom to scatter photons and this scattering pushes the atom back into position.
This phenomenon is why the chamber must be constructed from a non-magnetic material, so it does not interfere with the magnetic field inside the chamber.
Custom magneto-optical traps at Torr Scientific
Torr Scientific offers a custom design service for magneto-optical traps with up to fourteen horizontal and two vertical optical ports to allow laser access into the chamber.
The non-magnetic chambers can be constructed from either 316LN (or by request 304L) stainless steel, with fused silica optics.
Torr Scientific has manufactured a wide range of custom-built magneto-optical traps to fulfil customers’ requirements. Variations between chambers include differing lengths for the ports, different seals, or different flange sizes. An example of a custom magneto-optical trap is shown below.
In this project Torr utilised indium seals to avoid thermal distortion in the optics. This may be a consideration if maintaining a flat optic and minimising transmission wavefront error is important for the application of the chamber.
To enquire about custom magneto-optical traps, please contact our sales team.
Which AR coatings are available for magneto-optical traps?
Torr Scientific can offer magneto-optical traps with a wide range of anti-reflective coatings.
These coatings can offer great performance across a wide range of wavelengths. Typically, broadband anti-reflective coatings (BBAR) are chosen although other coating types are available.
A theoretical BBAR curve for fused silica targeting 500-1000nm is shown below:
These BBAR coatings are custom-made for your requirements. To request a theoretical transmission curve please contact our sales team with your wavelength range.
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