| Optical Kerr effect (OKE) spectroscopy has found broad use in monitoring ultrafast dynamics in transparent media. Interest is also developing in using OKE spectroscopy as a means of achieving contrast in nonlinear microscopy. I demonstrated that by using two pump pulses with independently-controllable polarizations, intensity and timing, different contributions to the OKE signal in liquids can be enhanced and suppressed. Then I characterize in detail the perpendicularly-polarized pulses used for the excitation step in OKE spectroscopy. The results indicate that the signal can be described well as arising from the sum of independent third-order responses initiated by each pump pulses. These experiments pave the way for using sequences of multiple pump pulses to single out the contribution of a single mode of interest. Such a technique would be of interest for performing mode-selective OKE microscopy. |
