Frontier physics
Optical trapping and laser cooling
Watch atoms held in an optical dipole potential and cooled by photon scattering. Examine the role of laser detuning in the force .
⚠ The simulation is illustrative; real trapping lasers can damage eyes — never look directly into a laser beam.
Equipment
- Optical dipole trap with simulated laser beams
- A cloud of point atoms moving in the trapping potential
- Sliders for parameter, noise level, and physical parameter
- Evolution plot of the quantities and a run-time control
Procedure
Watch atoms inside the optical trap
Run the simulation and drag to rotate the view. Atoms stay confined around the region of highest light intensity — the dipole potential; its depth scales as for a red-detuned laser.
Vary trap parameter and noise
Raise the trap-parameter slider to deepen the potential: the cloud shrinks and fewer atoms escape. Then raise the noise slider and watch random motion grow — analogous to temperature kicking atoms out of a shallow trap.
Connect to Doppler cooling
Read the quantity evolution in the second figure while changing the physical parameter. Red detuning makes atoms preferentially absorb photons opposing their motion (via the Doppler shift), so the scattering force opposes velocity and lowers temperature; predict whether the cloud will contract or expand before reducing the parameter.