# Inline self-diffraction dispersion-scan of over octave-spanning pulses in the single-cycle regime

## TL;DR

This paper introduces an inline self-diffraction dispersion-scan technique for characterizing over octave-spanning, single-cycle pulses, demonstrating its advantages over traditional second-harmonic generation methods in broad spectral ranges.

## Contribution

The paper develops and experimentally validates a new SD d-scan method that enables robust, inline measurement of ultra-broadband, single-cycle pulses beyond the spectral limits of SHG crystals.

## Key findings

- Successfully measured sub-4-fs pulses with over octave spectra
- SD d-scan outperforms SHG d-scan in spectral range and robustness
- Theoretical analysis confirms high efficiency of the SD process

## Abstract

We present an implementation of dispersion-scan based on self-diffraction (SD d-scan) and apply it to the measurement of over octave-spanning sub-4-fs pulses. The results are compared with second-harmonic generation (SHG) d-scan. The efficiency of the SD process is derived theoretically and compared with the spectral response retrieved by the d-scan algorithm. The new SD d-scan has a robust inline setup and enables measuring pulses with over-octave spectra, single-cycle durations and wavelength ranges beyond those of SHG crystals, such as the ultraviolet and the deep-ultraviolet.