Liver-related mortality in homeless-experienced adults over a 16-year period.

Homeless-experienced adults have higher liver-related mortality than the general population. The objective of our study was to examine temporal liver-related mortality trends and assess cause-specific liver-related mortality disparities in a large cohort of homeless-experienced adults. We linked a cohort of 60,092 adults who received care at Boston Health Care for the Homeless Program (BHCHP) from 2003-2017 to Massachusetts death occurrence files spanning 2003-2018.

Anomalous Temperature Effect in Weakly Coupled Superlattices: Carrier Transport in a THz Quantum Cascade Laser.

We present an investigation into the vertical transport through 13 different superlattice structures, where the well and barrier widths, doping concentration, dopant position, and contact layers were varied. Although superlattices have been extensively studied since 1970, there is a lack of publications on transport through superlattices similarly low doped as THz quantum cascade lasers (QCLs), for which the doping is in the 3-5×10^{10}  cm^{-2} range. The superlattices presented are doped in the same range as THz QCLs, with contact layers and fabrication comparable to high-temperature THz QCLs.

Nozaki-Bekki solitons in semiconductor lasers.

Optical frequency-comb sources, which emit perfectly periodic and coherent waveforms of light, have recently rapidly progressed towards chip-scale integrated solutions. Among them, two classes are particularly significant-semiconductor Fabry-Perót lasers and passive ring Kerr microresonators. Here we merge the two technologies in a ring semiconductor laser and demonstrate a paradigm for the formation of free-running solitons, called Nozaki-Bekki solitons.

Active mid-infrared ring resonators.

High-quality optical ring resonators can confine light in a small volume and store it for millions of roundtrips. They have enabled the dramatic size reduction from laboratory scale to chip level of optical filters, modulators, frequency converters, and frequency comb generators in the visible and the near-infrared. The mid-infrared spectral region (3-12 μm), as important as it is for molecular gas sensing and spectroscopy, lags behind in development of integrated photonic components.