Few-cycle pulse retrieval using amplitude swing technique.

Ultrashort pulses have garnered significant attention across various scientific disciplines and applications. In this paper, we demonstrate that the recently introduced amplitude swing technique is a robust method for characterizing pulses in the few-cycle temporal domain by analyzing compressed and chirped pulses from a Ti:Sapphire laser oscillator. The duration of the measured pulse for the case of best compression was 5.98 fs (Fourier limit 5.50 fs) corresponding to 2.2 cycles, while the chirped pulses were up to 15 times temporally stretched. The results obtained have been validated using the d-scan technique, showing excellent agreement in all situations. Therefore, the capability of the amplitude swing technique to measure ultra-broadband pulses in the few-cycle regime is demonstrated, as well as very far from optimum compression, while only being limited by the transparency and birefringence of its elements.

Generalizing amplitude swing modulation for versatile ultrashort pulse measurement.

In this work we broaden the amplitude modulation concept applied to the temporal characterization of ultrashort laser pulses with the amplitude swing technique. We theoretically study the effect of diverse types of relative amplitude and phase modulations. This variation of the replicas can be implemented by means of rotating zero-order waveplates to manipulate the delayed pulse replicas produced in a following multi-order waveplate, which can be more practical under certain conditions. We numerically simulate and study different scenarios under different modulations and for different noise levels and pulses. The proposed schemes are validated and compared through the experimental application to compressed and chirped pulses, confirming the applicability of the work. The simplicity, robustness and versatility of this ultrashort pulse measurement benefits the applications of ultrafast optics.

Near-infrared supercontinuum source by intracavity silica-based highly-nonlinear fiber.

Near-infrared supercontinuum generation by using silica-based highly-nonlinear fiber placed inside of the ring-cavity of an erbium-doped fiber laser pulsed by mode-locking is experimentally demonstrated. Only one erbium-doped fiber amplifier is employed to generate supercontinuum with a spectral width as long as 830 nm (from 1205 to 2035 nm) and a spectral power higher than -30 dBm/nm. To generate supercontinuum, it is not necessary a second amplifier to raise the power of the laser pulses coupled into the nonlinear fiber. Moreover, all the devices employed are commercial and available at any photonics laboratory. To the best of our knowledge, this is the first demonstration of this kind of device by pumping the nonlinear fiber in the third window of communications.