An impulse laser may be treated as a source of photons that are emitted during the time interval of the pulse which is followed by a time interval when no photons are produced. Pulses are periodically repeated. A laser beam of diameter $d=10$ microns is directed upward and is perpendicular to the thin foil surface which has an index of reflection $\rho =0.50$ (see the sketch of the experiment). The index of reflection of the surface is the ratio of the reflected energy to the impact energy. A pulse with duration of $0.13 \mathrm{ms}$ has a total energy of $10 \mathrm{J}$. What is the mass of the piece of foil that can be supported in the air solely by the light pressure of the laser beam?