Terahertz generation from ZnTe optically pumped above and below the bandgap

Population inversion in optically pumped asymmetric quantum well terahertz lasers

Terahertz surface plasmons in optically pumped graphene structures.

We analyze the surface plasmons (SPs) propagating along optically pumped single-graphene layer (SGL) and multiple-graphene layer (MGL) structures. It is shown that at sufficiently strong optical pumping when the real part of the dynamic conductivity of SGL and MGL structures becomes negative in the terahertz (THz) range of frequencies due to the interband population inversion, the damping of th...

Comparison of Zn1−xMnxTe/ZnTe multiple-quantum wells and quantum dots by below-bandgap photomodulated reflectivity

Large-area high density patterns of quantum dots with a diameter of 200 nm have been prepared from a series of four Zn0.93Mn0.07Te/ZnTe multiple quantum well structures of different well width (40 Å, 60 Å, 80 Å and 100 Å) by electron beam lithography followed by Ar-ion beam etching. Below-bandgap photomodulated reflectivity spectra of the quantum dot samples and the parent heterostructures were...

High Sample Rate Optically Pumped Helium Magnetometer

Optically pumped helium magnetometers are important instruments whichhave many applications in military, mass spectroscopy and space applications. In thispaper, the working principles of helium magnetometers have been explained. There isalso an introduction of a new method for finding the resonant frequency, which hasadvantages to the typical method such as more sample r...

Above-bandgap voltages from ferroelectric photovoltaic devices.

In conventional solid-state photovoltaics, electron-hole pairs are created by light absorption in a semiconductor and separated by the electric field spaning a micrometre-thick depletion region. The maximum voltage these devices can produce is equal to the semiconductor electronic bandgap. Here, we report the discovery of a fundamentally different mechanism for photovoltaic charge separation, w...