Imaging of DC induced second harmonic generation for species independent electric field measurements

Abstract

Proof of concept measurements are presented demonstrating a femtosecond localized E-Field measurement for species independent measurements. The measurement method utilizes electric field induced second harmonic generation for localized E-field measurements with a sub-picosecond temporal resolution possible. In the current work, a CCD camera is used as the detector and calibrations have been completed showing a minimum sensitivity on the order of 500 - 800 V/cm for the given experimental setup. Work has been completed to image the beam for several gases in order to demonstrate the versatility of the measurement method, as well as measurements verifying the expected dependence upon both electric field strength and pump beam intensity. Using a camera as the detector allows for the ability to look at the beam modal structure to better understand the polarization dependence of the nonlinear susceptibilities in the four wave mixing process.