Volume 12 Issue 7, July 2018

Efficient photon upconversion is desired for applications ranging from molecular sensing to solar-energy harvesting. Now, the population of hidden triplet state electrons, created on dye antennas and rare-earth-doped nanoparticles, has been amplified to brighten upconversion by five orders of magnitude.

Interferometric analysis of the weak light scattered from proteins makes it possible to determine their mass.

The finding that the quasi-1D crystal BaTiS₃ features a large optical anisotropy and a broadband birefringence spanning the infrared is likely to reignite interest in quasi-1D optical materials.

The demonstration of broadband, electrically tunable third-order nonlinear optical responses in graphene is promising for a host of nonlinear optical applications.

Using high-temperature gas mixtures as the generation medium to increase the translational velocity of Xe atoms through the focus of a femtosecond enhancement cavity, phase-matched extreme-ultraviolet emission at a repetition rate of 77 MHz and with an average power of ~ 2 mW in a single harmonic order is achieved.

Highly crystalline BaTiS₃ has been shown to exhibit record-breaking birefringence of 0.76 in the wavelength range of 7–16 μm. The large anisotropy is a result of its quasi-one-dimensional structure.

Previous predictions that light radiated by modes around a bound state in the continuum (BIC) condition should exhibit a vortex in the far-field polarization profile are experimentally confirmed. The findings shed light on the origin of BICs.

Lanthanide-doped upconverting nanoparticles exhibiting a 33,000 times increase in brightness and a 100 times increase in efficiency over bare upconverting nanoparticles are demonstrated. The findings are relevant in fields from solar energy to biophotonics.

Eigenmodes of photonic crystal defects have now been topologically protected in an experimental demonstration that also shows how to minimize the mode volume.

Laser-driven crosslinking of molecules at the cornea offers a non-invasive alternative to surgical correction of the refractive power of the eye.

While modifications of emission and absorption rates are commonplace in photonics, similar manipulations of emitter transition frequencies are challenging. Here, 2D polaritons in graphene are predicted to enable non-vertical electronic transitions in a quantum well, controlling the transition frequencies by inducing an effective non-locality.

Third-harmonic generation and four-wave mixing of light can be enhanced in graphene with gate tuning to adjust the doping level. The findings may lead to new graphene-based nonlinear optoelectronic devices.