  We report results of a high precision phase estimation based on a weak
measurements scheme using commercial light-emitting diode. The method is based
on a measurement of the imaginary part of the weak value of a polarization
operator. The imaginary part of the weak value appeared due to the measurement
interaction itself. The sensitivity of our method is equivalent to resolving
light pulses of order of attosecond and it is robust against chromatic
dispersion.
