Atomic units

Laser intensity conversion

Intensity [au] = Intensity [W.cm2] / 3.51e16 

Electric field strength

E [au] = E [V/m] / 5.14e11

Energy conversion

Energy [au] = Energy [eV] / 27.21

Time conversion

t [au] = t [fs] * 1000 / 24.2

Wavelength conversion

lambda [au] = lambda [nm] * 18.89

Angular frequency

omega [au] = 45.56 / lambda [nm]

Useful formulas in ultrafast physics

Wavelength-energy conversion

Ponderomotive energy