SEARCH Articles Figures Tables 3 " -order Raman spectroscopy polarization tensor Build-Up of the Polar Order Electric field poling, polar order First-Order Optical Polarization First-order polarization propagator First-order polarization propagator approximation Hadronic Vacuum Polarization Contribution of Order a(Za) Higher Order Electron-Loop Polarization Contributions Induced polar alignment order parameter Intensity third-order polarization Polar alignment order parameter Polar order Polar order Polar order stability Polar order, effect Polar order, photoisomerization-induced Polarization higher-order effects Polarization order parameter Polarization order-electric Polarization propagator third-order Polarization propagator zeroth-order Second order polarization propagator approximation Second-Order Polarization Propagator Second-Order Polarization Propagator Approximation model Second-order Polarization Propagator Approximation Calculations Second-order nonlinear polarization Second-order nonlinear polarization matter Second-order polarization propagator SOPPA) Second-order polarization propagator calculations Second-order polarization propagator correlation Second-order surface polarization Third-Order Optical Polarization and Non-linear Response Functions Third-order polarization Third-order polarization propagator approximation Zeroth-order polarization propagator approximation