Ion-Irradiated Laterally Graded Ni/C Multilayers: A Combined X-ray Standing Wave and X-ray Reflectivity Analysis

Abstract

An inversionless room temperature scheme for a far-infrared and THz laser with the possibility of the wide tuning of its working frequency is suggested. The scheme is based on usual room-temperature quantum cascade lasers operating in the mid-infrared range and the use of their output as a driving field for a supplementary semiconductor heterostructure where the inversionless lasing of the far-infrared or THz radiation takes place. This structure consists of a superlattice formed by quantum wells of a special design and is incorporated into a dielectric waveguide. The optimal parameters of this structure are calculated and its operation is simulated. As a result it is shown that the working frequency of such a device can be varied by more than two times via the simple change of the mid-infrared driving field intensity. Due to the high values of the latter the suggested inversionless laser is expected to operate in the pulsed mode. It can be used as a compact and convenient widely tunable source of the far-infrared and THz radiation for fundamental studies and various applications.

Ion‐beam‐induced mixing in a Si/Co/Si system involving ultrathin layers: A grazing‐incidence X‐ray standing‐wave study

“…The heat of mixing between Co and Si is negative (−12 kcal g −1 atom −1 ), which means that it is a highly miscible system in solid solution 6. Now, at higher ion fluence the effect of heat of mixing becomes dominant 27, 28 and the chemical drive may lead to compound formation. To investigate the possible formation of Co–Si compounds we carried out XRD experiments on the as‐deposited sample and the ion‐beam‐irradiated sample at the highest fluence (1 × 10 15 ions/cm 2 ) and the diffractograms are shown in Fig.…”