Terahertz Dielectric Properties of MgO Nanocrystals

Abstract

Terahertz properties of chemically synthesized MgO nanocrystals are studied by terahertz time-domain spectroscopy in the frequency range extending up to 3.7 THz. The experimentally determined optical and dielectric properties of the nanocrystalline MgO are compared with those of a bulk MgO single crystal. Three prominent resonance modes, which are essentially responsible for the dielectric properties of the nanostructured MgO in the terahertz regime, are characterized at ω 1 /(2π) ) 4.26 THz, ω 2 /(2π) ) 7.68 THz, and ω 3 /(2π) ) 12.18 THz and are well-described by a multiple-oscillator model through theoretical fitting. The MgO nanocrystals may find intriguing applications in developing terahertz quasi-optic components and terahertz spectroscopy.

Effect of annealing on the temperature-dependent dielectric properties of LaAlO3 at terahertz frequencies

“…The dielectric response of LAO was measured by a commercial THz-TDS system (TeraView Spectra 3000). From THz-TDS, we can directly obtain material dielectric parameters [11][12][13][14] …”

“…8 Our temperature-dependent ω 3 has not been reported before -it possibly originates from multiple phonon processes. 14 We now discuss the phonon stiffening with increasing temperature. Normally, the frequency change of every lattice mode is related to the rate of change in volume V of the crystal as: f f = −γ V V , where γ is an average Grüneisen constant.…”

Growth dependent optical properties of ZnMgO at THz frequencies

“…∞ is comparable to ZnO bulk, 3.705, but higher than to ZnO NWs = 1.75, as the ZnO NWs/air interface and dimensions of nanowires need to be taken into account. As the bulk plasma frequency of MgO (4.26 THz) [24] is smaller than bulk ZnO (12.25 THz) [25], a plasma frequency of MgO NWs smaller than ZnO NWs is assumed, from which a damping factor to match the experimental results is deduced, ( /2 ) x = (0.56 -0.61). As has been extracted from the experimental data, the carrier concentrations is estimated to = * * 0 2 2 , 5.83x10 14 -5.95x10 14 /cm 3 .…”

On the intrinsic optical bistability of a single Kerr nonlinear dielectric layer

“…The data fed into the multiple oscillator models are solely based on Ref. 30. The value of the resonance frequency used here is x 0 % 12:18 Â 10 12 Hz and e 1 ¼ 3.01.…”

“…The value of the resonance frequency used here is x 0 % 12:18 Â 10 12 Hz and e 1 ¼ 3.01. 30 The plasma frequency x p (The value of x at which the real part of the linear dielectric function e r ðxÞ goes to zero) is estimated to be x p % 1:23x 0 . The refractive index (RI) n 2 ¼ 11.713 at x ¼ 11.836 Â 10 12 Hz or at x ¼ 0.98x 0 .…”