High quality sub-two cycle pulses from compression of supercontinuum generated in all-normal dispersion photonic crystal fiber

Abstract

We demonstrate nonlinear pulse compression based on recently introduced highly coherent broadband supercontinuum (SC) generation in all-normal dispersion photonic crystal fiber (ANDi PCF). The special temporal properties of the octave-spanning SC spectra generated with 15 fs, 1.7 nJ pulses from a Ti:Sapphire oscillator in a 1.7 mm fiber piece allow the compression to 5.0 fs high quality pulses by linear chirp compensation with a compact chirped mirror compressor. This is the shortest pulse duration achieved to date from the external recompression of SC pulses generated in PCF. Numerical simulations in excellent agreement with the experimental results are used to discuss the scalability of the concept to the single-cycle regime employing active phase shaping. We show that previously reported limits to few-cycle pulse generation from compression of SC spectra generated in conventional PCF possessing one or more zero dispersion wavelengths do not apply for ANDi PCF.

Limits of coherent supercontinuum generation in normal dispersion fibers

“…In contrast, low temporal coherence associated with large pulse-to-pulse fluctuations often plays a precision or resolution limiting role, for example in modalities using the coherence directly as content in the acquired signal, such as optical coherence tomography [5,6] or coherent antiStokes Raman scattering (CARS) spectroscopy [7]. Since spectral amplitude and phase fluctuations also translate into temporal jitter, ultrafast photonics applications usually demand SC sources with a high degree of coherence to enable, for example, beam synchronization and extraction of time-resolved information in multi-beam pump-probe techniques, nonlinear pulse compression, multimodal bio-photonic imaging, or coherent control experiments [8][9][10][11][12][13][14][15].…”

Coherent supercontinuum bandwidth limitations under femtosecond pumping at 2 µm in all-solid soft glass photonic crystal fibers

“…Although this in particular is true also for anomalous-dispersion pumped soliton-based SC sources (provided that ultrashort pulses are used so the SC spectrum develops over a propagation distance shorter than the modulation instability length-scale [12]), the advantage of an ANDi SC over a soliton-based SC is a uniform temporal profile of the SC pulse. This enables recompression close to the single-cycle limit using phase-compensation methods [13]. ANDi SC pumped at around 1.55 µm and extending past 2.0 µm with their redshifted side-band have already been reported [14,15].…”

Tunable stoichiometry of BCxNy thin films through multitarget pulsed laser deposition monitored viain situellipsometry

“…Another drawback of this type of SC is the lack of coherence and the fact that in the time domain, it does not exhibit a single-pulse waveform but has the form of a noise-like train of spikes. However, pumping in the normal dispersion region of optical fibers could benefit from the generation of octave-spanning supercontinua, which are characterized by the preservation of a single-pulse waveform in the time domain and perfect temporal coherence and spectral properties [2][3][4] suitable for efficient external recompression. This is important because of the practical demands of few-cycle laser pulses in time-resolved studies of fundamental processes in physics, chemistry, and biology.…”