Quantitative near-field characterization of surface plasmon polaritons on monocrystalline gold platelets.

Near-field microscopy allows for visualization of both the amplitude and phase of surface plasmon polaritons (SPPs). However, their quantitative characterization in a reflection configuration is challenging due to complex wave patterns arising from the interference between several excitation channels. Here, we present near-field measurements of SPPs on large monocrystalline gold platelets in the visible.

Infrared-spectroscopic, dynamic near-field microscopy of living cells and nanoparticles in water.

Infrared fingerprint spectra can reveal the chemical nature of materials down to 20-nm detail, far below the diffraction limit, when probed by scattering-type scanning near-field optical microscopy (s-SNOM). But this was impossible with living cells or aqueous processes as in corrosion, due to water-related absorption and tip contamination. Here, we demonstrate infrared s-SNOM of water-suspended objects by probing them through a 10-nm thick SiN membrane.

High prevalence of DNA damage repair gene defects and TP53 alterations in men with treatment-naïve metastatic prostate cancer -Results from a prospective pilot study using a 37 gene panel.

Background: Defects in DNA damage repair genes characterize a subset of men with prostate cancer and provide an attractive opportunity for precision oncology approaches. The prevalence of such perturbations in newly diagnosed, treatment-naïve patients with a high risk for lethal disease outcome, however, has not been sufficiently explored.

Patients And Methods: Prostate cancer specimens from 67 men with newly diagnosed early onset, localized high-risk/locally advanced or metastatic prostate cancer were included in this prospective pilot study.

MHz-repetition-rate, sub-mW, multi-octave THz wave generation in HMQ-TMS.

We demonstrate the first megahertz (MHz) repetition-rate, broadband terahertz (THz) source based on optical rectification in the organic crystal HMQ-TMS driven by a femtosecond Yb:fibre laser. Pumping at 1035 nm with 30 fs pulses, we achieve few-cycle THz emission with a smooth multi-octave spectrum that extends up to 6 THz at -30 dB, with conversion efficiencies reaching 10 and an average output power of up to 0.38 mW.

Wavelength scaling of terahertz pulse energies delivered by two-color air plasmas.

We address the long-standing problem of anomalous growth observed in the terahertz (THz) energy yield from air plasmas created by two-color laser pulses, as the fundamental wavelength λ is increased. Using two distinct optical parametric amplifiers (OPAs), we report THz energies scaling like λ0α with large exponents 5.6≤α≤14.

Terahertz time-domain spectroscopy of zone-folded acoustic phonons in 4H and 6H silicon carbide.

We investigate the dielectric properties of the 4H and 6H polytypes of silicon carbide in the 0.1-19 THz range, below the fundamental transverse-optical phonons. Folding of the Brillouin zone due to the specific superlattice structure of the two polytypes leads to activation of acoustic phonon modes.

Terahertz near-field imaging of dielectric resonators.

As an alternative to metallic resonators, dielectric resonators can increase radiation efficiencies of metasurfaces at terahertz frequencies. Such subwavelength resonators made from low-loss dielectric materials operate on the basis of oscillating displacement currents. For full control of electromagnetic waves, it is essential that dielectric resonators operate around their resonant modes.

Removing image artefacts in wire array metamaterials.

Hyperlenses and hyperbolic media endoscopes can overcome the diffraction limit by supporting propagating high spatial frequency extraordinary waves. While hyperlenses can resolve subwavelength details far below the diffraction limit, images obtained from them are not perfect: resonant high spatial frequency slab modes as well as diffracting ordinary waves cause image distortion and artefacts. In order to use hyperlenses as broad-band subwavelength imaging devices, it is thus necessary to avoid or correct such unwanted artefacts.

Metamaterial fibres for subdiffraction imaging and focusing at terahertz frequencies over optically long distances.

Using conventional materials, the resolution of focusing and imaging devices is limited by diffraction to about half the wavelength of light, as high spatial frequencies do not propagate in isotropic materials. Wire array metamaterials, because of their extreme anisotropy, can beat this limit; however, focusing with these has only been demonstrated up to microwave frequencies and using propagation over a few wavelengths only. Here we show that the principle can be scaled to frequencies orders of magnitudes higher and to considerably longer propagation lengths.