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Publications
Publications (345)
The noise-like pulse regime of optical fiber lasers is highly complex, and associated with multiscale emission of random sub-picosecond pulses underneath a much longer envelope. With the addition of highly nonlinear fiber in the cavity, noise-like pulse lasers can also exhibit supercontinuum broadening and the generation of output spectra spanning...
We report multipass broadband photoacoustic spectroscopy of trace gases in the mid-infrared. The measurement principle of the sensor relies on supercontinuum-based Fourier transform photoacoustic spectroscopy (FT-PAS), in which a scanning interferometer modulates the intensity of a mid-infrared supercontinuum light source and a cantilever microphon...
While recent high-profile assassination attempts have once again brought nerve agents (NAs) into the spotlight, the current portfolio of NA sensors lack a sufficient combination of high performance and field-deployability. Here, we report a novel optical sensor for the detection of gaseous NAs with a potential to fill this gap. The technique is bas...
We show using numerical simulations that data driven discovery using sparse regression can be used to extract the governing differential equation model of ideal four-wave mixing in a nonlinear Schrödinger equation optical fibre system. Specifically, we consider the evolution of a strong single frequency pump interacting with two frequency detuned s...
The need to measure high repetition rate ultrafast processes cuts across multiple areas of science. The last decade has seen tremendous advances in the development and application of new techniques in this field, as well as many breakthrough achievements analyzing non-repetitive optical phenomena. Several approaches now provide convenient access to...
The generation of a two-octave supercontinuum from the visible to mid-infrared (700–2800 nm) in a non-silica graded-index multimode fiber is reported. The fiber design is based on a nanostructured core comprised of two types of drawn lead-bismuth-gallate glass rods with different refractive indices. This yields an effective parabolic index profile...
We report multipass broadband photoacoustic spectroscopy of trace gases in the mid-infrared. The measurement principle of the sensor relies on supercontinuum-based Fourier transform photoacoustic spectroscopy (FT-PAS), in which a scanning interferometer modulates the intensity of a mid-infrared supercontinuum light source and a cantilever microphon...
Neural networks have been recently shown to be highly effective in predicting time-domain properties of optical fiber instabilities based only on analyzing spectral intensity profiles. Specifically, from only spectral intensity data, a suitably trained neural network can predict temporal soliton characteristics in supercontinuum generation, as well...
We present an erratum to our Letter [Opt. Lett.47, 802 (2022)10.1364/OL.448571]. This erratum corrects an error in the sign of one of the higher-order dispersion coefficient used in the simulations of Figs. 2 and 4, as well as in Figs. S1 and S3. The simulations in the original Letter were performed using the correct value, and therefore this corre...
The nonlinear propagation of ultrashort pulses in optical fibers depends sensitively on the input pulse and fiber parameters. As a result, the optimization of propagation for specific applications generally requires time-consuming simulations based on the sequential integration of the generalized nonlinear Schrödinger equation (GNLSE). Here, we tra...
We report real-time simultaneous measurement of average water vapor temperature and concentration in a full-scale industrial boiler, and further map the concentration profile in the boiler, by a broadband lidar employing a custom supercontinuum source.
We report online measurement of water vapor temperature and concentration in a high temperature industrial boiler using a broadband lidar employing a supercontinuum laser covering the ro-vibrational absorption spectrum of water molecules at 1.2 – 1.6 μm.
We demonstrate broadband supercontinuum generation with self-cleaning dynamics in a non-silica multimode graded-index fiber with enhanced nonlinearity and trans-parency window compared to silica.
We teach a feed-forward neural network the differential propagation dynamics of the generalized nonlinear Schrödinger equation, allowing for fast and memory-efficient emulation of nonlinear propagation scenarios in optical fibers from pulse compression to supercontinuum generation.
We demonstrate the generation of a broadband supercontinuum spanning from 950 nm to 2900 nm with signatures of self-cleaning dynamics in a specially designed tellurite graded-index multimode fiber. Our results are the first to report such a large bandwidth and a quasi-Gaussian transverse intensity distribution in the mid-infrared regime.
We combine a programmable spectral filter and machine learning via a genetic algorithm to optimize nonlinear fiber propagation dynamics to generate an on-demand target spectrum.
The nonlinear propagation of ultrashort pulses in optical fiber depends sensitively on both input pulse and fiber parameters. As a result, optimizing propagation for specific applications generally requires time-consuming simulations based on sequential integration of the generalized nonlinear Schr\"odinger equation (GNLSE). Here, we train a feed-f...
The physics and applications of fiber-based supercontinuum (SC) sources have been a subject of intense interest over the last decade, with significant impact on both basic science and industry. New uses for SC sources are also constantly emerging due to their unique properties that combine high brightness, multi-octave frequency bandwidth, fiber de...
The physics and applications of fiber-based supercontinuum (SC) sources have been a subject of intense interest over the last decade, with significant impact on both basic science and industry. New uses for SC sources are also constantly emerging due to their unique properties that combine high brightness, multi-octave frequency bandwidth, fiber de...
Understanding dynamical complexity is one of the most important challenges in science. Significant progress has recently been made in optics through the study of dissipative soliton laser systems, where dynamics are governed by a complex balance between nonlinearity, dispersion, and energy exchange. A particularly complex regime of such systems is...
Solitons are coherent structures that describe the nonlinear evolution of wave localizations in hydrodynamics, optics, plasma and Bose-Einstein condensates. While the Peregrine breather is known to amplify a single localized perturbation of a carrier wave of finite amplitude by a factor of three, there is a counterpart solution on zero background k...
The generation of a two-octave supercontinuum from the visible to mid-infrared (700 - 2800 nm) in a non-silica graded-index multimode fiber is reported. The fiber design is based on a nanostructured core comprised of two types of drawn lead-bismuth-gallate glass rods with different refractive indices. This structure yields an effective parabolic in...
We experimentally demonstrate the generation of a shortwave infrared supercontinuum in an uncladded silicon nitride (Si3N4) waveguide with extreme polarization sensitivity at the pumping wavelength of 2.1 µm. The air-clad waveguide is specifically designed to yield anomalous dispersion regime for transverse electric (TE) mode excitation and all-nor...
We demonstrate computational spectral-domain ghost imaging by encoding complementary Fourier patterns directly onto the spectrum of a superluminescent laser diode using a programmable spectral filter. Spectral encoding before the object enables uniform spectral illumination across the beam profile, removing the need for light collection optics and...
The propagation of ultrashort pulses in optical fibre plays a central role in the development of light sources and photonic technologies, with applications from fundamental studies of light–matter interactions to high-resolution imaging and remote sensing. However, short pulse dynamics are highly nonlinear, and optimizing pulse propagation for appl...
We investigate the noise characteristics of Fourier transform photoacoustic spectroscopy, improve the sensitivity of the technique by a factor of 20 and demonstrate our system’s ability to analyze complex gas mixtures.
Solitons are coherent structures that describe the nonlinear evolution of wave localizations in hydrodynamics, optics, plasma and Bose-Einstein condensates. While the Peregrine breather is known to amplify a single localized perturbation of a carrier wave of finite amplitude by a factor of three, there is a counterpart solution on zero background k...
Recent years have seen the rapid growth and development of the field of smart photonics, where machine-learning algorithms are being matched to optical systems to add new functionalities and to enhance performance. An area where machine learning shows particular potential to accelerate technology is the field of ultrafast photonics — the generation...
Supercontinuum generation is a highly nonlinear process that exhibits unstable and chaotic characteristics when developing from long pump pulses injected into the anomalous dispersion regime of an optical fiber. A particular feature associated with this regime is the long-tailed “rogue wave”-like statistics of the spectral intensity on the long-wav...
We demonstrate the generation of a low-noise, octave-spanning mid-infrared supercontinuum from 1700 to 4800 nm by injecting femtosecond pulses into the normal dispersion regime of a multimode step-index chalcogenide fiber with 100 µm core diameter. We conduct a systematic study of the intensity noise across the supercontinuum spectrum and show that...
The propagation of ultrashort pulses in optical fibre displays complex nonlinear dynamics that find important applications in fields such as high power pulse compression and broadband supercontinuum generation. Such nonlinear evolution however, depends sensitively on both the input pulse and fibre characteristics, and optimizing propagation for app...
Supercontinuum generation is a highly nonlinear process that exhibits unstable and chaotic characteristics when developing from long pump pulses injected into the anomalous dispersion regime of an optical fiber. A particular feature associated with this regime is the long-tailed "rogue wave"-like statistics of the spectral intensity on the long wav...
We demonstrate the generation of a low-noise, octave-spanning mid-infrared supercontinuum from 1700 to 4800 nm by injecting femtosecond pulses into the normal dispersion regime of a multimode step-index chalcogenide fiber with 100 $\mu$m core diameter. We conduct a systematic study of the intensity noise across the supercontinuum spectrum and show...
We demonstrate single-pixel imaging in the spectral domain by encoding Fourier probe patterns onto the spectrum of a superluminescent laser diode using a programmable optical filter. As a proof-of-concept, we measure the wavelength-dependent transmission of a Michelson interferometer and a wavelength-division multiplexer. Our results open new persp...
Numerical simulations of a dissipative soliton-similariton laser are shown to reproduce a range of instabilities seen in recent experiments. The model uses a scalar nonlinear Schrödinger equation map, and regions of stability and instability are readily identified as a function of gain and saturable absorber parameters. Studying evolution over mult...
We use the dispersive Fourier transform to spectrally characterize “multipulse soliton complexes” in a dissipative soliton fiber laser operating in the soliton-similariton regime. These multipulse complexes consist of two or more circulating dissipative solitons of picosecond duration, but with temporal separations of ∼5–40 ns, three orders of magn...
We use machine learning techniques to predict the peak intensity and temporal shift of extreme red-shifted rogue solitons in supercontinuum generation from simulated single-shot spectral intensity profiles without any phase information.
We use recurrent neural network to successfully predict the spectral evolution of cohererent supercontinuum along propagation in an optical fiber. The network performs particularly well for a wide range of input pulse parameters.
We report the generation of a low noise, octave-spanning supercontinuum in the normal dispersion regime of a multimode chalcogenide fiber with 100 μm core size. The noise performances are characterized in different output wavelength bands.
We review our recent work on the real-time characaterization of ultrafast non-repetitive signals in fiber-optics systems and modeling of nonlinear dynamics using machine learning.
We demonstrate a supercontinuum lidar to measure water vapor concentration and temperature in a high-temperature power plant boiler. The method utilizes three wavelength bands at 1200-1600 nm wavelength range and allows single-port measurements.
We review the study of rogue waves and related instabilities in optical and oceanic environments, with particular focus on recent experimental developments. In optics, we emphasize results arising from the use of real-time measurement techniques, whilst in oceanography we consider insights obtained from analysis of real-world ocean wave data and co...
Over a decade ago, an analogy was drawn between the generation of large ocean waves and the propagation of light fields in optical fibres. This analogy drove numerous experimental studies in both systems, which we review here. In optics, we focus on results arising from the use of real-time measurement techniques, whereas in oceanography we conside...
We developed a short-range light detection and ranging system using a supercontinuum (SC) source spectrally tailored to cover the ro-vibrational transition energies of desired components of a flue gas. The system enables remote measurements of the gas parameters, including temperature and concentration which play a key role in the performance of co...
We demonstrate experimentally ghost optical coherence tomography using a broadband incoherent supercontinuum light source with shot-to-shot random spectral fluctuations. The technique is based on ghost imaging in the spectral domain where the object is the spectral interference pattern generated from an optical coherence tomography interferometer i...
Ghost imaging constructs an image by correlating two signals: one that interacts with an object but possesses no spatial information, and the other that contains spatial information but does not interact with the object. Ghost imaging can be extended into the time domain by using laser intensity fluctuations to reconstruct an unknown time-varying p...