Thermal · photothermal heating

Heating in a focused laser (optical tweezers)

Questions & answers

Does an optical trap heat the particle?

Yes, whenever the particle absorbs at the laser wavelength: metal particles in a trap can warm by many kelvin. The calculator gives the temperature from the particle's absorption in the focused beam.

What does it compute?

The absorbed power and temperature rise of a sphere in a tightly focused laser of chosen numerical aperture and polarization, from generalized Lorenz–Mie theory.

Is absorption by the water included?

No: the heating comes from the particle's own absorption. Near-infrared trapping lasers also heat water slightly on their own, which adds to it.

The temperature of a particle in a tightly focused trapping laser, in one click.