Efficient optical-to-terahertz conversion in large-area InGaAs photo-Dember emitters with increased indium content.

In this Letter, optical-to-terahertz (THz) conversion of 800 nm femtosecond laser pulses in large-area bias-free InGaAs emitters based on photo-Dember (PD) and lateral photo-Dember (LPD) effects is experimentally investigated. We use metamorphic buffers to grow sub-micrometer thick layers with indium mole fractions =0.37, 0.

Synthesis and Properties of Zinc-Modified Hydroxyapatite.

Hydroxyapatites modified with metal ions are the main inorganic components of bone tissue and are approved for use as components for biocomposites and coatings for surgical implants. This study examined prototypes of functional materials for bone implants based on hydroxyapatite modified with zinc ions. Zinc-modified hydroxyapatite was composed and synthesized.

Electro-optic sampling of terahertz waves by laser pulses with an edge-cut spectrum in birefringent crystal.

We demonstrate a terahertz detection technique based on variations of the energy of femtosecond laser pulses with an edge-cut spectrum in birefringent electro-optic crystal-periodically poled lithium niobate (PPLN). The method is compared with the standard electro-optic detection scheme utilizing GaP crystal. The experimental results show that the studied technique is suited for use with birefringent crystals and allows one to achieve a much better response to the terahertz wave radiation at quasi-phase-matching frequencies of PPLN.

Terahertz radiation from bismuth surface induced by femtosecond laser pulses.

We report on the first experimental observation of terahertz (THz) wave generation from bismuth mono- and polycrystalline samples irradiated by femtosecond laser pulses. Dependencies of the THz signal on the crystal orientation, optical pulse energy, incidence angle, and polarization are presented and discussed together with features of the sample surfaces. The optical-to-THz conversion efficiency was up to two orders of magnitude higher than for metal at a moderate fluence of ∼1  mJ/cm.

Terahertz time-domain electro-optic measurements by femtosecond laser pulses with an edge-cut spectrum.

Balanced electro-optic detection techniques of terahertz wave radiation are proposed based on variations of the energy and ellipticity of laser pulses with an edge-cut spectrum. The techniques are compared with the standard electro-optic detection scheme utilizing laser pulses with Gaussian spectrum shape. Our calculations and measurements show that the studied schemes have a much better response to the terahertz wave radiation at high frequencies compared with the standard one.