Effect Of Dual-frequency Research Articles

Plasma Dynamics in a Dual-Frequency Paul Trap Using Tsallis Distribution

This paper theoretically analyzes the motion of a collection of charged particles in a dual-frequency Paul trap. We derive analytical expressions for the single particle trajectory and the plasma distribution function assuming Tsallis statistics to see how this trap configuration is different from a conventional Paul trap. The introduction of a secondary RF frequency in a dual-frequency Paul trap allows for a modification of the spatial extent of confinement of charged particles. The plasma distribution function and temperature have been found to be periodic if the two driving frequencies are rationally related and the resulting period of plasma oscillation is given by the LCM of the time periods corresponding to the two driving frequencies and their linear combinations. The plasma temperature is spatially varying and the time-averaged plasma distribution has been found to be double humped beyond a certain spatial threshold, indicating the presence of certain instabilities. The effect of dual frequency in a Paul trap on the energy level shifts of the atomic orbitals has been investigated and the uncertainties in second order Doppler and Stark shift are found to be of the same order as that of a single-frequency Paul trap.

Numerical and experiment analysis of nanosecond pulsed laser drilling with dual frequency

Nanosecond pulsed laser drilling is one of the most common material removal processes. Dual focus laser micro drilling is high aspect ratio micro drilling techniques. Tan et al. (2003) proposed the concept of dual focus with dual frequency femtosecond laser micro drilling on PMMA. An investigation of dual frequency micro drilling with nanosecond pulsed laser on 500 μm silicon wafer has been reported in this paper with mathematical modelling supported with experimental results. Numerical modelling has been done to study the effect of dual frequency drilling with respect to intensity distribution and resultant effect on the focused spot size. Experiments were done with single and dual wavelengths with 532 nm and 1,064 nm at different pulse energies and the results were found in reasonable match with theoretical values.

Effect of dual frequency on the plasma characteristics in an internal linear inductively coupled plasma source

An internal-type linear inductive antenna, referred to as a “double comb-type antenna,” was used as a large area plasma source with a substrate size of 880×660mm2 (fourth generation glass size). The effects of the dual frequency (2 and 13.56MHz) radio frequency (rf) power to the antenna as well as the power ratio on the plasma characteristics were investigated. High-density plasma on the order of 1.7×1011cm−3 could be obtained with a dual frequency power of 5kW (13.56MHz) and 1kW (2MHz) at a pressure of 15mTorr Ar. This plasma density was lower than that obtained for the double comb-type antenna using a single frequency alone (5kW, 13.56MHz). However, the use of the dual frequency with a rf power ratio of approximately 1(2MHz):5(13.56MHz) showed better plasma uniformity than that obtained using the single frequency. Plasma uniformity of 6.1% could be obtained over the substrate area. Simulations using FL2L code confirmed the improvement in the plasma uniformity using the dual frequency to the double comb-type antenna.

Effect of dual frequency on sonochemical reaction rates

An ultrasonic reactor that combined a standing-wave-type transducer and a horn-type emitter was constructed and the ultrasonic frequency of the standing-wave-type transducer was varied and the sonochemical reaction rates were estimated. The synergy effect was observed below 100 kHz. In order to consider the mechanism of effect of synergy, the acoustic noise, the sonochemical luminescence and the bubble behavior in the reactor were investigated. The frequency spectrum of acoustic noise indicated that the synergy effect came from the increase of number of cavitation bubbles.

Improving Multiplexability of Polymer-Dispersed Liquid Crystal Films by Dual Frequency Addressing

Abstract We have studied the effect of dual frequency addressing (DFA) on the number of rows Nmax which can be multiplexed in a liquid crystal display incorporating a PDLC film. Nmax depends strongly on the required contrast ratio. For the film we studied and a contrast ratio of nine, only direct driving is possible without DFA. With DFA and the same contrast ratio, the number of multiplexable rows can be increased to nearly seven. Higher operating voltages are required to obtain this increased multiplexability. At maximum multiplexability, the off-state voltage increases by about 60 Vrms while the on-state voltage increases by less than 30 Vrms; most of the increase is due to the high frequency voltage component needed for DFA. To switch between the off-and the on-states, it is sufficient to switch only the low frequency component of the driving voltage; this can be done with the drivers which would be used in a direct drive mode.