All-fiber frequency agile triple-frequency comb light source.

Tricomb spectroscopy unveils a new dimension to standard linear and nonlinear spectroscopic analysis, offering the possibility to reveal the almost real-time evolution of complex systems with unprecedented accuracy. Current triple comb configurations are based on the use of mode-locked lasers, which impose constraints on the comb parameters, and require complex electronic synchronization, thus limiting potential applications. In this paper, we present the experimental demonstration of a new type of all-fiber, self-phase-locked, frequency-agile tri-comb light source.

Understanding ecological restoration potential: The role of water resources and slope gradient limits.

Ecological restoration is one of the most feasible ways to mitigate climate change and conserve ecosystems. However, the scope, intensity, effectiveness, and future potential of ecological restoration are restricted by unfavorable environmental conditions, especially limited water resources and complex topography. This paper proposes an assessment framework of ecological restoration potential under the coupled limits of water resources and slope gradient to quantitatively assess ecological restoration potential (ERP) under these two limiting factors.

Intra-envelope four-wave mixing in optical fibers.

We report experimentally on the phenomenon of intra-envelope four-wave mixing (FWM) in optical fibers. We demonstrate that the non-linear interaction between two pulse trains operating at the same repetition rate, but with slightly different carrier frequencies, leads by FWM to the generation of new components within their spectral envelops. The frequency differences between the FWM components and the pump lines are in the RF domain, making it almost impossible to observe the process using a standard optical spectrum analyzer.

Birefringence based multi-focus fs/ps-CARS spectroscopy for thermometry and hyperspectral microscopy.

We present a multi-focus fs/ps-CARS scheme to perform spectroscopy on multiple points simultaneously for gas phase measurements and microscopy, using a single birefringence crystal or a combination of birefringent stacks. CARS performances are first reported for 1 kHz single-shot N spectroscopy on two points set few millimeters apart, allowing thermometry measurements to be carried out in the vicinity of a flame. Then, simultaneous acquisition of toluene spectra is demonstrated on two points set 14 µm apart in a microscope setup.

Range-resolved detection of boundary layer stable water vapor isotopologues using a ground-based 1.98 µm differential absorption LIDAR.

This paper presents a first demonstration of range-resolved differential absorption LIDAR (DIAL) measurements of the water vapor main isotopologue H O and the less abundant semi-heavy water isotopologue HDO with the aim of determining the isotopic ratio. The presented Water Vapor and Isotope Lidar (WaVIL) instrument is based on a parametric laser source emitting nanosecond pulses at 1.98 µm and a direct-detection receiver utilizing a commercial InGaAs PIN photodiode.