Comparative study on diode-pumped continuous wave laser at 607 nm using differently doped Pr3+:LiYF4 crystals and wavelength tuning to 604 nm

We comparatively study an InGaN laser-diode-pumped continuous-wave laser at ～607 nm (? polarization) using differently doped Pr :LiYF4 single crystals. Maximum output power and slope efficiency at this wavelength were up to 209 mWand 47.1%, respectively, using a 0.2 at. % doped and 8 mm sample. Findlay-Clay analysis shows roundtrip losses, including reabsorption loss at this particular emission of about 1.2% using the 0.2 at. % doped sample, which is lower than that of samples with higher doping concentrations at 0.5 and 1 at. %. Using a 0.15 mm glass plate as a Fabry-Perot etalon, a maximum output power of 73 mW was achieved at ～604 nm (π polarization) with slope efficiency of 17.2% for what is believed to be the highest result currently

Histidine modulates amyloid-like assembly of peptide nanomaterials and confers enzyme-like activity

Abstract Amyloid-like assembly is not only associated with pathological events, but also leads to the development of novel nanomaterials with unique properties. Herein, using Fmoc diphenylalanine peptide (Fmoc–F–F) as a minimalistic model, we found that histidine can modulate the assembly behavior of Fmoc–F–F and induce enzyme-like catalysis. Specifically, the presence of histidine rearranges the β structure of Fmoc–F–F to assemble nanofilaments, resulting in the formation of active site to mimic peroxidase-like activity that catalyzes ROS generation. A similar catalytic property is also observed in Aβ assembled filaments, which is correlated with the spatial proximity between intermolecular histidine and F-F. Notably, the assembled Aβ filaments are able to induce cellular ROS elevation and damage neuron cells, providing an insight into the pathological relationship between Aβ aggregation and Alzheimer’s disease. These findings highlight the potential of histidine as a modulator in amyloid-like assembly of peptide nanomaterials exerting enzyme-like catalysis

InGaN-LD-pumped Pr3+: LiYF4 continuous-wave laser at 915 nm

We demonstrate the first InGaN-LD-pumped room temperature and continuous-wave laser operation of a Pr3+: LiYF4 crystal at 915 nm. A maximum output power up to 78 mW with a laser slope efficiency of about 17% is obtained. The round-trip optical losses are estimated to be about 0.45%, and the M2 beam quality factors measured in x and y dimensions are about 1.07 and 1.04, respectively