Patent ID: 7940390

Claim:
A method for precise detection of the timing error between laser pulses, the method comprising: directing first and second input pulses through a nonlinear medium and a group dispersion/delay element, generating a first-pass sum-frequency component from the first and second input pulses and changing the relative positions of the first and second input pulses; directing the first-pass sum-frequency component and the first and second input pulses to an inline dichroic mirror that passes the sum-frequency component and reflects the first and second input pulses; detecting the energy of the sum-frequency component that passed through the inline dichroic mirror; directing the reflected first and second input pulses back through the group dispersion/delay element and nonlinear medium, changing the relative positions of the first and second input pulses and generating a second-pass sum-frequency component from the reflected first and second input pulses; detecting the energy of the second-pass sum-frequency component; and comparing the energy of the first-pass sum-frequency component with the energy of the second-pass sum-frequency component to determine the relative positions of the first and second input pulses.