Experimental demonstrations of high-Q superconducting coplanar waveguide resonators

Abstract

We successfully designed and fabricated an absorption-type of superconducting coplanar waveguide (CPW) resonators. The resonators are made from a niobium film (about 160 nm thick) on a high-resistance Si substrate, and each resonator is fabricated as a meandered quarter-wavelength transmission line (one end is short to the ground and another end is capacitively coupled to a through feedline). With a vector network analyzer we measured the transmissions of the applied microwave through the resonators at ultra-low temperature. The obtained loaded quality factors are significantly high, i.e. up to ~10 6 . When the temperature increases slowly from the base temperature (20 mK), the resonance frequencies of the resonators are blue shifted and the quality factors are lowered slightly. In principle, this type of device can integrate a series of CPW resonators with a common feedline, making it a promising candidate as the data bus for coupling distant solid-state qubits and the sensitive detector of single photons.superconducting coplanar waveguide resonator, resonance frequency, quality factor Citation:

Scheme for realizing quantum dense coding via entanglement swapping

“…The time for information transfer is π/2J ∼ 0.22ns, which is much smaller than the cavity decay time 2π/k ∼ 14ns for k/2π = 70 MHz. In the case of superconducting resonators, we set J/2π = 1.9 MHz, ω/2π = 1.88 GHz, ω q3 = 1.9 GHz and the coupling between the resonator and superconducting qubit is taken to be g/2π = 6.3 MHz [64,65,66]. The decay parameters are chosen to be k/2π = 1.8 kHz and γ/2π = 1 kHz.…”

Detection of electron spin resonance down to 10 K using localized spoof surface plasmon

“…The shift of the resonant frequency (f res ) and the variation in the loaded quality factor (Q-factor) of the M 2 mode for the empty LSSPR with temperature are shown in figure 11. The Q-factor is calculated using the relation, Qfactor = f res ∆ f 3dB , where ∆ f 3dB is the bandwidth at +3dB above the minimum forward transmission coefficient S 21 value which occurs at f res [24], [25], [26]. A shift of 67 MHz is observed in f res at 10 K in comparison to its value at 295 K. Thermal contraction and change in dielectric properties of the microwave laminate [21] can qualitatively explain this shift [27], [28], [29].…”

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“…The length l relates to the resonant frequency f 0 , the light speed c, and the effective dielectric constant eff = ( r + 1)/2 as [17],…”

“…A layout structure of the resonator is shown in Fig. 1, where perfectly sharp border between the transmission line and the ground plate is seen [17]. The device is glued with GE varnish inside a gold-plated copper sample box.…”