Due to soliton energy quantization, most soliton molecules generated in mode-locked fiber lasers are formed by pulses with similar properties. Soliton trapping and collision between two dissimilar dissipative solitons is presented with distinctive energy, duration, chirp, and spectra in a versatile mode-locked Tm fiber laser which can emit different dissipative solitons simultaneously. Depending on the intracavity polarization settings, the group velocity difference between a strong broadband pulse and a weak narrowband pulse can be controlled and new soliton interaction dynamics are captured in real-time with a polarization-resolving dispersive Fourier transform setup. Unique partial spectral interference patterns and double-scale autocorrelation traces confirm the existence of ‘heteronuclear’ molecules formed by two dissimilar dissipative solitons with high pulse coherence. We believe the findings here represent a new type of soliton molecules in a mode-locked laser and can provide deeper insights into dissipative soliton interaction dynamics.

We demonstrate the deterministic control of femtosecond dual-comb soliton motion in an Er:fiber laser. Introducing fast intra-cavity modulation, we control individual solitons within two interlaced soliton combs in the harmonically-modelocked state. Upon extra-cavity recombination of both combs, we can obtain reconfigurable pulse pairs at arbitrary delays. Based on realtime spectroscopy, we resolve the transient inter-soliton trajectories.The approach employs laser-intrinsic soliton dynamics and provides all-optically swept pulse pairs for i.e. pump-probe spectroscopy at ⪆kHz scanning frequencies.

We present new work demonstrating the single-shot measurement of the intensity and phase of sub-picosecond optical pulses and waveforms without ambiguity at measurement times of 1 microsecond. While the technique has an optical front-end, back-end detection is done using 70 GHz electronics effectively extending the bandwidth of the electronics by a factor of 20-50. Measurements were made using both multishot and single-shot approaches. Multishot pulses were compared to separate cross-Frequency Resolved Optical Gating (X-FROG) measurements. Generation of the test pulses, as well as measurement results, will be presented.

Lately, there has been a renewed attention to the study of multimode signals and their ultrafast interactions. One fascinating phenomenon in this field is known as nonlinear multimode dispersive waves. These waves are frequently observed and hold significant applications across diverse physical systems. While the single-mode case of these waves has been widely researched, the multimode scenario remains relatively unexplored. Understanding and studying nonlinear multimode dispersive waves holds great significance in predicting and analyzing wave phenomena within many systems. In our lab, we developed multimode time lens, which can measure the temporal and spatial dynamics of signals inside multimode fibers. We study the interactions of multimode dispersive waves, in both frequency and time domain. We use the multimode time lens we developed to image and analyze the temporal dynamics between the different spatial modes, as well as the modes coupling over time and the energy transfer between them. In this talk, we will present our measurement system in detail and describe our novel results on multimode dispersive waves interactions.

Coherent anti-Stokes Raman scattering (CARS) is a highly effective Non-Linear Optical (NLO) microscopy technique for label-free vibrational imaging of unperturbed samples. We present a novel scheme for video-rate wide-field CARS microscopy over a wide (up to 100-μm diameter) field of view, based on an Ytterbium amplified laser followed by white-light generation and optical parametric amplification. It records the full fingerprint region of the molecular vibrational spectrum and enables chemically-specific real-time characterization of fast dynamics with down to few-milliseconds time resolution. The system can perform either real-time imaging at single Raman shifts or acquire three-dimensional hypercubes, chemically richer in information.

Spatial frequency modulated imaging (SPIFI) employs a structured line-shaped illumination, able to resolve beyond conventional resolution limits for coherent light with high speed. It produces image harmonics, with each order carrying a higher resolution. To date this method used rotating reticles to produce the necessary structured illumination, limiting image acquisition to about 100 μs. Here, we introduce a single-shot approach. We show that a super-resolved 1D image can be acquired with a single femtosecond pulse, with potential acquisition rates in the tens of kHz.

Dispersive Fourier method gives access to spectral information by mapping them in the time domain. This facilitates shot-to-shot spectroscopy of rapidly changing systems. We adapted this technique to demonstrate time-resolved THz spectroscopy at 50 kHz repetition rate by encoding the THz waveform onto the spectral components of spectrally broadened (NIR) ultrafast laser pulses.

Single-shot detection of THz electric field can be required for complete real time characterization of low repetition rate pulsed THz sources. Here, we present a single-shot detection electro-optic system designed to record long THz pulses (100+ ps) with sub ps resolution. To achieve this performance, the system exploits the Diversity Electro Optic Sampling scheme. This setup will be used to monitor shot by shot the long THz pulses (⪆ 100 ps) generated for an accelerator project.

This presentation will focus on the development of a bright multi-octave spanning, phase-stable frontend, accompanied by a cutting-edge near-petahertz detection methodology. These tools have been designed explicitly for field-resolved detection of ultra-short pulses under ambient air conditions. By employing a frequency up-conversion process, the detection bandwidth limitation associated with Silicon-based detectors is circumvented. As a result, the system allows for broadband spectroscopic detection at overtone and combination band regions.

Dressing matter excitations with cavity photons can create novel, exotic quantum states. Ultrastrong coupling, where the ratio of vacuum Rabi frequency and carrier frequency of light, ΩR/ωc, approaches unity, has enabled vacuum-field modified transport, polaritonic chemistry, or strong mode squeezing and entanglement. Past investigations of this regime of cavity quantum electrodynamics (c-QED) focused on coupling of a single pair of light and matter modes, in equilibrium. Here, we discuss conceptually new extremes of c-QED. We demonstrate subcycle control of deep-strong coupling, where ΩR/ωc is collapsed from 1.3 to zero within 5% of the optical cycle duration, leading to characteristic trailing oscillations of the extinguished polariton states. Moreover, we investigate coherent subcycle nonlinearities of multiple cavity polaritons and observe dynamical mixing between otherwise orthogonal modes. Our most recent structures demonstrate extremely strong, multi-mode coupling of 20 matter resonances and multiple cavity modes over 6 optical octaves, boosting the number of virtual cavity photons beyond unity for the first time while achieving a record coupling strength of ΩR/ωc = 3.19.

Extremely high beam-to-radiation energy conversion efficiencies can be obtained in a THz FEL using a strongly tapered helical undulator at the zero-slippage resonant condition, where a circular waveguide is used to match the radiation group velocity to the electron beam longitudinal velocity. We report on single-shot Electro-Optic Sampling (EOS) based measurements of the broadband THz FEL radiation pulses emitted in this regime. The technique allows full reconstruction of the THz field waveform. The measurements are performed varying the input electron beam energy in the undulator providing insights on the complex dynamics in a waveguide FEL.

Photonic time-stretch is a very efficient technique for recording THz signals in single-shot, with high MHz-rate repetition rates. However, up to now, the range of applications suffered from the high cost of the oscilloscopes (or ADC boards) required for the readout, often in the 8-30 GHz range. We present a design for a single-shot THz digitizer (or time-domain spectrometer) using mid-IR probes, and low bandwith oscilloscopes (down to 1 GHz). Measurements at the THz beamline of synchrotron SOLEIL will be presented. Performances in terms of effective number of points versus costs will also compared to state-of-art single-shot TDS systems. These new designs are expected to considerably extend the application range of high repetition rate single-shot electro-optic detection and time-domain spectroscopy.

This study investigates structured light beams and wavelength modulation spectroscopy for advanced plasma diagnostics. Structured light, with its spatial and spatiotemporal structures, enables enhanced signal-to-noise ratios and high-resolution measurements of plasma velocity distribution functions, especially in devices with limited access. The research introduces a confocal Laser-Induced Fluorescence setup using a Laguerre-Gaussian annular laser beam, achieving a spatial resolution of approximately 5 mm at a 300 mm focal distance, with potential to reach up to 1 mm. This advancement could broaden the scope of applications to other diagnostic methods in industrial plasma sources and electric propulsion systems. Additionally, WM spectroscopy, effective in complex plasma environments, measures spectral line profile derivatives, improving spectral resolution and reducing background noise. Findings from confocal measurements with structured light and WM-LIF in an industrial plasma device show that these techniques can provide insights into plasma dynamics not accessible through conventional diagnostics, indicating significant potential for plasma diagnostics applications.