Out-of-Band Fiber-Optic Time and Frequency Transfer Using Asymmetric and Symmetric Opto-Electronic Repeaters.

Signal repeaters for fiber-optic communication can be realized with back-to-back connected transceivers. This configuration can provide high gain ( ≈ 30 dB) at low cost, and the needed semiconductor lasers and modulators can be realized for practically any relevant wavelength. Unfortunately, for time and frequency (TF) transfer the uncorrelated wavelength drifts in the transceiver lasers can compromise transfer stability, and device replacement due to failure may result in large time offsets that have to be measured via global navigation satellite services (GNSS).

Single-molecule measurements of viral ssRNA packaging.

Genome packaging of double-stranded RNA (dsRNA) phages has been widely studied using biochemical and molecular biology methods. We adapted the existing in vitro packaging system of one such phage for single-molecule experimentation. To our knowledge, this is the first attempt to study the details of viral RNA packaging using optical tweezers.

Temperature and pH dependence of DNA ejection from archaeal lemon-shaped virus His1.

The archaeal virus His1 isolated from a hypersaline environment infects an extremely halophilic archaeon Haloarcula hispanica. His1 features a lemon-shaped capsid, which is so far found only in archaeal viruses. This unique capsid can withstand high salt concentrations, and can transform into a helical tube, which in turn is resistant to extremely harsh conditions.

DNA ejection from an archaeal virus--a single-molecule approach.

The translocation of genetic material from the viral capsid to the cell is an essential part of the viral infection process. Whether the energetics of this process is driven by the energy stored within the confined nucleic acid or cellular processes pull the genome into the cell has been the subject of discussion. However, in vitro studies of genome ejection have been limited to a few head-tailed bacteriophages with a double-stranded DNA genome.

Stroboscopic supercontinuum white-light interferometer for MEMS characterization.

We used a supercontinuum-based scanning white-light interferometer to characterize the oscillation of a MEMS device. The output of a commercially available supercontinuum light source (FiberWare Ilum II USB) was modulated to achieve stroboscopic operation. By synchronizing the modulation frequency of the source to the sample oscillation, dynamic 3-D profile measurements were recorded.