THz polariton laser using an intracavity Mg:LiNbO crystal with protective Teflon coating.

An enhancement in the performance of a THz polariton laser based on an intracavity magnesium-doped lithium niobate crystal (Mg:LiNbO) in surface-emitted (SE) configuration is demonstrated resulting from the deposition of a protective Teflon coating on the total internal reflection surface of the crystal. In this cavity geometry the resonating fields undergo total internal reflection (TIR) inside the lithium niobate, and laser damage to that surface can be a limiting factor in performance. The protective layer prevents laser damage to the crystal surface, enabling higher pump power, yielding higher THz output power and wider frequency tuning range.

Deep-penetrating photodynamic therapy with KillerRed mediated by upconversion nanoparticles.

Unlabelled: The fluorescent protein KillerRed, a new type of biological photosensitizer, is considered as a promising substitute for current synthetic photosensitizes used in photodynamic therapy (PDT). However, broad application of this photosensitiser in treating deep-seated lesions is challenging due to the limited tissue penetration of the excitation light with the wavelength falling in the visible spectral range. To overcome this challenge, we employ upconversion nanoparticles (UCNPs) that are able to convert deep-penetrating near infrared (NIR) light to green light to excite KillerRed locally, followed by the generation of reactive oxygen species (ROS) to kill tumour cells under centimetre-thick tissue.

Stimulated polariton scattering in an intracavity RbTiOPO crystal generating frequency-tunable THz output.

A high power, frequency-tunable THz source based on intracavity stimulated polariton scattering (SPS) in RbTiOPO (RTP) is demonstrated for the first time. Frequency tunable THz output was obtained from 3.10 to 4.

The Brazilian time and frequency atomic standards program.

Cesium atomic beam clocks have been the workhorse for many demanding applications in science and technology for the past four decades. Tests of the fundamental laws of physics and the search for minute changes in fundamental constants, the synchronization of telecommunication networks, and realization of the satellite-based global positioning system would not be possible without atomic clocks. The adoption of optical cooling and trapping techniques, has produced a major advance in atomic clock precision.