All-optical thermometry using a single multimode fiber endoscope and diamond nanoparticles containing nitrogen vacancy centers.

Photoluminescence (PL) spectra from diamond nanoparticles containing negative nitrogen vacancy centers were measured by using a single multimode fiber endoscope combined with a high-sensitivity spectroscopy system. A laser light spot was produced at the distal end of the endoscope and the PL spectra from a temperature-controlled ensemble of diamond nanoparticles were measured. After calibrating the sensitivity and wavelength of the spectroscopy system, the temperature dependence of the zero-phonon line peak wavelength similar to those previously reported was obtained.

Formation scheme of quantum point contacts based on nanogaps using field-emission-induced electromigration.

We propose a new fabrication scheme of quantum point contacts (QPCs) composed of nanogaps at room temperature. This scheme is based on electromigration induced by a field emission current, which is so-called "activation." By applying the activation to ferromagnetic Ni nanogaps with sub-10 nm separation, QPCs can be easily obtained at room temperature.

Tuning of tunnel resistance of nanogaps by field-emission-induced electromigration using current source mode.

A newly investigated technique for the tuning of the tunnel resistance of nanogaps using electromigration method induced by a field emission current is presented to reduce the power consumption during the process. The method is called "activation" and is demonstrated with a current source. Planar-type initial nanogaps of Ni separated by 20-80 nm were defined on SiO2/Si substrates via electron-beam lithography and the lift-off process.