Photonic time stretch fieldoscopy: single-shot electric field detection at near-petahertz bandwidth

TL;DR

This work introduces photonic time-stretch fieldoscopy (PTF) to achieve single-shot detection of electric fields carrying near-petahertz information. By integrating fieldoscopy with a nonlinear time lens and enforcing a time-lens condition $D_s=-D_f$, PTF maps ultrafast waveforms into a time-stretched domain, enabling real-time, scan-free measurements via sum-frequency generation and spectral overlap. Numerical UPPE-based simulations demonstrate a usable spectral overlap bandwidth of 425–500 THz, reveal how focal dispersion $D_f$ controls the temporal aperture and a scaling-factor trade-off, and show that trailing-edge Lorentzian features can be resolved under the time-lens condition. The discussion outlines practical implementations (DFG/FWM, angularly dispersive readout), linear and nonlinear dispersion challenges (including TOD matching), and the potential for real-time petahertz spectroscopy and non-repetitive ultrafast dynamics studies. Overall, PTF offers a route to attosecond-scale field measurements in a single shot, enabling rapid exploration of fragile or non-repetitive ultrafast phenomena with high sensitivity and dynamic range.

Abstract

Accessing the electric field of light with petahertz bandwidths in ambient air is a rapidly advancing frontier, essential for probing ultrafast dynamics driven by classical or quantum ultrashort pulses. Near-petahertz fieldoscopy has recently demonstrated sub-cycle access to light-matter interactions, enabling label-free spectro-microscopy of liquids and solids with unprecedented spatiotemporal resolution, detection sensitivity, and dynamic range. However, current implementations still rely on temporal scanning and averaging over many laser pulses. Here, we introduce photonic time-stretch fieldoscopy, enabling single-shot electric-field detection at near-petahertz frequencies. Numerical results demonstrate that integrating fieldoscopy with a nonlinear time lens enables the real-time acquisition of ultrashort optical waveforms with a detection bandwidth approaching petahertz. The resulting large temporal aperture and attosecond resolution allow direct single-shot detection of transient electric fields generated in solid or liquid samples. This concept opens new avenues for petahertz electronics, ultrafast spectro-microscopy, and the study of dynamic, non-repetitive optical phenomena

Figures (5)

• Figure 1: Photonic time-stretch Fieldoscopy (PTF) for single-shot detection of the electric field of light at near-petahertz bandwidth. The field detection srivastava_near-petahertz_2024 is performed under the time-lens condition. Two approaches can be employed to detect the signal carrying the field information: a) utilizing photonic time stretch and balanced photodetection at GHz sampling rates, b) utilizing polarization-resolved spectrometry, CMOS sensor, and computational balancing. $\text{D}_{\text{s}}$: signal dispersion; $\text{D}_{\text{f}}$: focal dispersion; QWP: quarter waveplate; WP: Wollaston prism; BPD: balanced photodiode.
• Figure 2: a) The temporal overlap between the signal pulse (purple electric field) stretched by $D_s$=-2110fs and the focal pulse (black envelope) stretched by $D_f$=2110fs. b) Sum frequency spectrum resulting from the interaction of the stretched focal pulse ($D_f$=2110fs) and the FTL signal pulse ($D_s = 0$) is shown in the orange curve, while the teal curve corresponds to the sum frequency spectrum in which the signal pulse is stretched by $D_s = -D_f$. The black curve indicates the portion of the focal-pulse spectrum that overlaps with the sum-frequency spectrum. c) The corresponding resolved electric fields of the signal pulse from the generated sum frequency spectra in panel (a). The resolved electric field under the time-lens condition $D_s = -D_f$ (teal) matches the original signal pulse. In contrast, the electric field retrieved for $D_s = 0$ (orange) exhibits an additional temporal chirp that is absent in the original signal pulse. The SOB spans from 425 THz to 500 THz.
• Figure 3: a) Overcompensating or undercompensating the focal dispersion by applying $\text{D}_s = -2637.5fs\squared$ (purple curve) or $\text{D}_s = -1582.5fs\squared$ (orange curve) results in a down-chirped or up-chirped retrieved electric field of the signal. The teal curve shows the time-lens condition for $\text{D}_s = -2110fs\squared$. The inset shows a magnified view of all three resolved electric fields at time zero. b) The corresponding spectra and spectral phases. c) The spectra of the temporally gated resolved signal pulse. The gated region is shown in gray in panel a).
• Figure 4: a) The PTF temporal aperture and scaling factor as a function of $D_f$, under the time lens condition $D_f = -D_s$. b) Signal spectra retrieved for varying focal-pulse bandwidths centered at 345THz under the time-lens condition. The SOB spans from 425 THz to 500 THz.
• Figure E1: a) The electric field of the signal pulse. b) The signal spectrum. c) The electric field of the focal pulse. d) The focal spectrum.