| 摘要 |
<p>A method and an apparatus are provided for measuring the transverse moments of the electromagnetic field associated with an optical beam, wherein the beam is caused to pass through a slit, perpendicular to the beam propagation direction, a scanning of the beam is effected relative to the slit to generate a relative oscillatory motion between the beam and the slit in a direction perpendicular to the slit and to the propagation direction of the beam, a periodic electrical signal is generated consisting of pulses at a frequency half the frequency of the oscillatory motion, and whose amplitude and shape is dependent on the intensity distribution of the beam fraction which has passed through the slit, the periodic signal is resolved into its spectral components,the amplitude values of such components are measured, and the moment values are derived from the amplitude values so measured.</p> |
