Electro-optic characterization of synthesized infrared-visible light fields

Abstract

The measurement and control of light field oscillations enable the study of ultrafast phenomena on sub-cycle time scales. Electro-optic sampling (EOS) is a powerful field characterization approach, in terms of both sensitivity and dynamic range, but it has not reached beyond infrared frequencies. Here, we show the synthesis of a sub-cycle infrared-visible pulse and subsequent complete electric field characterization using EOS. The sampled bandwidth spans from 700 nm to 2700 nm (428 to 110 THz). Tailored electric-field waveforms are generated with a two-channel field synthesizer in the infrared-visible range, with a full-width at half-maximum duration as short as 3.8 fs at a central wavelength of 1.7 µm (176 THz). EOS detection of the complete bandwidth of these waveforms extends it into the visible spectral range. To demonstrate the power of our approach, we use the sub-cycle transients to inject carriers in a thin quartz sample for nonlinear photoconductive field sampling with sub-femtosecond resolution.

Principal frequency, super-bandwidth, and low-order harmonics generated by super-oscillatory pulses

“…We can conclude that the concept of principal frequency can be more suitable in the characterization of the main frequency of pulses emerging from complex synthesis techniques, instead of the conventional central frequency (wavelength), which is the standard experimental parameter used for that purpose (see for example Refs. [32,33,[43][44][45]).…”

Electric Field Measurement of Femtosecond Time-Resolved Four-Wave Mixing Signals in Molecules

“…In an all optical measurement of light-matter interactions, the amplitude and phase of the emitted electric field provide complete information. With electric field metrology demonstrated at THz -PHz frequencies [1][2][3][4], field-resolved spectroscopy at high sensitivity is now possible in this frequency range [5]. In the case of nonlinear optical spectroscopy such as four-wave mixing spectroscopy, the emitted signal is related to the induced third-order polarization in the medium and is determined by the third-order nonlinear response tensor 𝜒 (3) 𝑖 𝑗 𝑘𝑙 that can offer insight into the electronic character of the system being studied.…”

“…With electric field metrology demonstrated at THz -PHz frequencies [1][2][3][4], field-resolved spectroscopy at high sensitivity is now possible in this frequency range [5]. In the case of nonlinear optical spectroscopy such as four-wave mixing spectroscopy, the emitted signal is related to the induced third-order polarization in the medium and is determined by the third-order nonlinear response tensor 𝜒 (3) 𝑖 𝑗 𝑘𝑙 that can offer insight into the electronic character of the system being studied. Measuring the electric field of the nonlinear signal on ultrafast time scales offers access to the real-time behavior of the nonlinear polarization and hence the real and imaginary parts of the 𝜒 (3) 𝑖 𝑗 𝑘𝑙 tensor, as the system dynamically evolves.…”

“…In the case of nonlinear optical spectroscopy such as four-wave mixing spectroscopy, the emitted signal is related to the induced third-order polarization in the medium and is determined by the third-order nonlinear response tensor 𝜒 (3) 𝑖 𝑗 𝑘𝑙 that can offer insight into the electronic character of the system being studied. Measuring the electric field of the nonlinear signal on ultrafast time scales offers access to the real-time behavior of the nonlinear polarization and hence the real and imaginary parts of the 𝜒 (3) 𝑖 𝑗 𝑘𝑙 tensor, as the system dynamically evolves. Typical nonlinear spectroscopy techniques, like optical Kerr effect (OKE) spectroscopy [6,7] and degenerate four-wave mixing (DFWM) [8], measure the intensity of the nonlinear signal light, which is proportional to the magnitude of 𝜒 (3) 𝑖 𝑗 𝑘𝑙 .…”

“…Measuring the electric field of the nonlinear signal on ultrafast time scales offers access to the real-time behavior of the nonlinear polarization and hence the real and imaginary parts of the 𝜒 (3) 𝑖 𝑗 𝑘𝑙 tensor, as the system dynamically evolves. Typical nonlinear spectroscopy techniques, like optical Kerr effect (OKE) spectroscopy [6,7] and degenerate four-wave mixing (DFWM) [8], measure the intensity of the nonlinear signal light, which is proportional to the magnitude of 𝜒 (3) 𝑖 𝑗 𝑘𝑙 . In the optical heterodyne (OHD) configuration of OKE, a local oscillator is introduced which allows a measurement of the real and imaginary parts of 𝜒 (3) 𝑖 𝑗 𝑘𝑙 [9,10].…”