Sub two-cycle soliton-effect pulse compression at 800 nm in Photonic Crystal Fibers

The possibility of soliton self-compression of ultrashort laser pulses down to the few-cycle regime in photonic crystal fibers is numerically investigated. We show that efficient sub-two-cycle temporal compression of nanojoule-level 800 nm pulses can be achieved by employing short (typically 5-mm-long) commercially available photonic crystal fibers and pulse durations of around 100 fs, regardless of initial linear chirp, and without the need of additional dispersion compensation techniques. We envisage applications in a new generation of compact and efficient sub-two cycle laser pulse sources.Comment: 16 pages, 6 figure

Two-photon laser scanning fluorescence microscopy using photonic crystal fibre

We report the application of a simple yet powerful modular pulse compression system, based on photonic crystal fibres which improves upon incumbent twophoton laser scanning fluorescence microscopy techniques. This system provided more than a 7-fold increase in fluorescence yield when compared with a commercial two-photon microscopy system. From this, we infer pulses of infrared radiaton of less than 35 fs duration reaching the sample

Mimicking the nonlinear dynamics of optical fibers with waveguide arrays: towards a spatiotemporal supercontinuum generation

We numerically demonstrate the formation of the spatiotemporal version of the so-called diffractive resonant radiation generated in waveguide arrays with Kerr nonlinearity when a long pulse is launched into the system. The phase matching condition for the diffractive resonant radiation that we have found earlier for CW beams also works well in the spatiotemporal case. By introducing a linear potential, one can introduce a continuous shift of the central wavenumber of a linear pulse, whereas in the nonlinear case one can demonstrate that the soliton self-wavenumber shift can be compensated by the emission of diffractive resonant radiation, in a very similar fashion as it is done in optical fibers. This work paves the way for designing unique optical devices that generate spectrally broad supercontinua with a controllable directionality by taking advantage of the combined physics of optical fibers and waveguide arrays.Comment: arXiv admin note: substantial text overlap with arXiv:1210.520

Strong group velocity dispersion compensation with phase-engineered sheet metamaterials

Resonant metamaterials usually exhibit substantial dispersion, which is considered a shortcoming for many applications. Here we take advantage of the ability to tailor the dispersive response of a metamaterial introducing a new method of group-velocity dispersion compensation in telecommunication systems. The method consists of stacking a number of highly dispersive sheet metamaterials and is capable of compensating the dispersion of optical fibers with either negative or positive group-velocity dispersion coefficients. We demonstrate that the phase-engineered metamaterial can provide strong group-velocity dispersion management without being adversely affected by large transmission loss, while at the same time offering high customizability and small footprint.Comment: 10 pages, 4 figure

Chromatic dispersion monitoring for high-speed WDM systems using two-photon absorption in a semiconductor microcavity

This paper presents a theoretical and experimental investigation into the use of a two-photon absorption (TPA) photodetector for use in chromatic dispersion (CD) monitoring in high-speed, WDM network. In order to overcome the inefficiency associated with the nonlinear optical-to-electrical TPA process, a microcavity structure is employed. An interesting feature of such a solution is the fact that the microcavity enhances only a narrow wavelength range determined by device design and angle at which the signal enters the device. Thus, a single device can be used to monitor a number of different wavelength channels without the need for additional external filters. When using a nonlinear photodetector, the photocurrent generated for Gaussian pulses is inversely related to the pulsewidth. However, when using a microcavity structure, the cavity bandwidth also needs to be considered, as does the shape of the optical pulses incident on the device. Simulation results are presented for a variety of cavity bandwidths, pulse shapes and durations, and spacing between adjacent wavelength channels. These results are verified experimental using a microcavity with a bandwidth of 260 GHz (2.1 nm) at normal incident angle, with the incident signal comprising of two wavelength channels separated by 1.25 THz (10 nm), each operating at an aggregate data rate of 160 Gb/s. The results demonstrate the applicability of the presented technique to monitor accumulated dispersion fluctuations in a range of 3 ps/nm for 160 Gb/s RZ data channel

Infrared attosecond field transients and UV to IR few-femtosecond pulses generated by high-energy soliton self-compression

Infrared femtosecond laser pulses are important tools both in strong-field physics, driving X-ray high-harmonic generation, and as the basis for widely tuneable, if inefficient, ultrafast sources in the visible and ultraviolet. Although anomalous material dispersion simplifies compression to few-cycle pulses, attosecond pulses in the infrared have remained out of reach. We demonstrate soliton self-compression of 1800 nm laser pulses in hollow capillary fibers to sub-cycle envelope duration (2 fs) with 27 GW peak power, corresponding to attosecond field transients. In the same system, we generate wavelength-tuneable few-femtosecond pulses from the ultraviolet (300 nm) to the infrared (740 nm) with energy up to 25 $\mu$J and efficiency up to 12 %, and experimentally characterize the generation dynamics in the time-frequency domain. A compact second stage generates multi-$\mu$J pulses from 210 nm to 700 nm using less than 200 $\mu$J of input energy. Our results significantly expand the toolkit available to ultrafast science.Comment: 8 pages, 5 figure