Limits of the detection of microplastics in fish tissue using stimulated Raman scattering microscopy.

We demonstrate the detection sensitivity of microplastic beads within fish tissue using stimulated Raman scattering (SRS) microscopy. The intrinsically provided chemical contrast distinguishes different types of plastic compounds within fish tissue. We study the size-dependent signal-to-noise ratio of the microplastic beads and determine a lower boundary for the detectable size.

Spectrally resolved ultrafast transient dynamics of a femtosecond fiber-feedback optical parametric oscillator.

We report on spectrotemporal transient dynamics in a femtosecond fiber-feedback optical parametric oscillator (FFOPO) system. Burst modulation of the pump beam in combination with dispersive Fourier transformation sampling allows to record single-pulse signal spectra at 41 MHz sampling rate. Therefore, each individual pulse of the signal transients can be spectrally resolved.

Hybrid fiber-solid-state laser with 3D-printed intracavity lenses.

Microscale 3D-printing has revolutionized micro-optical applications ranging from endoscopy, imaging, to quantum technologies. In all these applications, miniaturization is key, and in combination with the nearly unlimited design space, it is opening novel, to the best of our knowledge, avenues. Here, we push the limits of miniaturization and durability by realizing the first fiber laser system with intra-cavity on-fiber 3D-printed optics.

3D stimulated Raman spectral imaging of water dynamics associated with pectin-glycocalyceal entanglement.

Pectin is a heteropolysaccharide responsible for the structural integrity of the cell walls of terrestrial plants. When applied to the surface of mammalian visceral organs, pectin films form a strong physical bond with the surface glycocalyx. A potential mechanism of pectin adhesion to the glycocalyx is the water-dependent entanglement of pectin polysaccharide chains with the glycocalyx.

High-harmonic spectroscopy of quantum phase transitions in a high-Tc superconductor.

We report on the nonlinear optical signatures of quantum phase transitions in the high-temperature superconductor YBCO, observed through high harmonic generation. While the linear optical response of the material is largely unchanged when cooling across the phase transitions, the nonlinear optical response sensitively imprints two critical points, one at the critical temperature of the cuprate with the exponential growth of the surface harmonic yield in the superconducting phase and another critical point, which marks the transition from strange metal to pseudogap phase. To reveal the underlying microscopic quantum dynamics, a strong-field quasi-Hubbard model was developed, which describes the measured optical response dependent on the formation of Cooper pairs.