Second harmonic generation (SHG) is an effective way to generate short wavelength laser with high power. The SHG accompanied the absorptions of fundamental waves and waves, which converts a fraction two deposit energy into heat, causing temperature gradient along radial direction periodically poled potassium titanyl phosphate (PPKTP) crystal. inhomogeneous distribution causes thermal lensing in...

An intermodal switch based on optically induced (through the Kerr effect) periodic coupling in a two-mode waveguide is described and demonstrated. A high-power pump beam injected into the two modes of the waveguide produces a periodic modulation of the refractive-index profile with a period equal to the modal beat length, which causes coupling between the two modes of a simultaneously injected ...

Nonrotating ("locked") magnetic islands often lead to complete losses of confinement in tokamak plasmas, called major disruptions. Here locked islands were suppressed for the first time, by a combination of applied three-dimensional magnetic fields and injected millimeter waves. The applied fields were used to control the phase of locking and so align the island O point with the region where th...

The idea of using a resonant cavity to enhance conversion efficiency in cw second-harmonic generation was first discussed by Ashkin et al.,' who found that the conversion efficiency can be greatly increased by resonating either the fundamental or the harmonic field. Because of its simplicity, the scheme of employing a resonator to build up the fundamental power is the one most widely used in pr...

A system is being tested for recovery of rf power by conversion to DC pulsed power. The system consists of a cyclotron autoresonance accelerator (CARA) [1,2], and a single stage depressed collector (Fig. 1). A 50 kV, 5 A electron beam is injected into CARA, and up to 1 MW of S-band rf power is absorbed by the beam with efficiency exceeding 95%. The beam then passes to a single stage depressed c...

A lot of oil and gas reservoirs have been or will be abandoned in petroleum industry. In this study, we pointed out that these oil and gas reservoirs might be transferred into exceptional enhanced geothermal reservoirs with very high temperatures by oxidizing the residual oil with injected air. A concept to generate power from these exceptional enhanced geothermal reservoirs by using geothermal...