Quantum Susceptibilities in Time?Domain Sampling of Electric Field Fluctuations

Electro-optic sampling has emerged as a new quantum technique enabling measurements of electric field fluctuations on subcycle time scales. In second-order nonlinear material, the terahertz are imprinted onto polarization properties an ultrashort probe pulse in near infrared. The statistics this time-domain signal calculated, incorporating nature involved fields right from beginning. A microscopic theory electro-optic process is developed adopting ensemble noninteracting three-level systems model for material. It found that response medium can be separated into conventional part, which exploited also coherent amplitudes, and contributions, independent state input. Interactions between mediated by vacuum causing response. Conditions under classical serves good approximation determined how sampled reconstructed demonstrated. complementary regime, serve spectroscopic tool to study pure susceptibilities matter.