| abstract |
A method and apparatus that determines a concentration of ions implanted in a material is described. The method includes the steps of: (1) passing an excitation pulse through a diffracting mask (e.g., a phase or amplitude mask) to generate at least two excitation laser sub-pulses; (2) irradiating a region of the material with a grating pattern, formed by overlapping two excitation laser sub-pulses in time and space to initiate a time-dependent response (e.g., a change in refractive index) in the region; (3) diffracting a probe laser pulse having a duration that is at least long as the time-dependent response off the region to generate a time-dependent signal beam; (4) detecting the time-dependent signal beam to generate a signal waveform; and (5) processing the signal waveform to determine the concentration of ions implanted in the material. |