Frequency modulation of the superconducting parallel-plate microwave resonator by laser irradiation

Tsindlekht, M. I.; Golosovsky, M.; Chayet, H.; Davidov, D.; Chocron, Sidney

doi:10.1063/1.112521

Cited by 27 publications

(22 citation statements)

References 11 publications

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“…A synthesized signal generator (transmitted microwave power ≈ -15 to 0 dBm) excited a resonant mode of the CPW resonator. The absorbed laser power produces a thermal spot on the HTS film surface at any location x, y of the probe, oscillating in time with the frequency of laser beam modulation f m. The thermal interaction of the probe with the sample shifted both f0 and Q of the device due to changes in the local magnetic penetration depth and the stored energy in the resonator [32,34,39]. This caused a change in the S12(f) transmission curve that is proportional to the local rf current density squared JRF 2 (x,y) at the location of the probe, and leads to a change in transmitted power P [see Fig.…”

Section: Basic Principles Of Ltlsm Imagingmentioning

confidence: 99%

Microwave Current Imaging in Passive HTS Components by Low-Temperature Laser Scanning Microscopy (LTLSM)

2006

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distributed parameters in SC films as a function of the local critical current [27]. It is possible to manifest local resistive characterization of the SC transition [28][29][30], the spatial variations of magnetic and electromagnetic fields [31][32][33][34], and to carry out 2-D defectoscopy of structural and technological faults in operating SC devices and circuits [35][36][37]. In this work, we apply the LTLSM technique to analyze the redistribution of rf current flow in the vicinity of typical microdefects in YBCO films leading to anomalously high rf photoresponse, and possibly to nonlinear microwave behavior of SC devices. We have used the LTLSM technique for a spatially resolved investigation of the microwave transport properties, nonlinearities and material inhomogeneities in an operating coplanar waveguide YBa2Cu3O7-d (YBCO) microwave resonator on an LaAlO3 (LAO) substrate. The influence of twin-domain blocks, inplane rotated grains, and micro-cracks in the YBCO film on the nonuniform rf current distribution were measured with a micrometer-scale spatial resolution. The impact of the peaked edge currents and rf field penetration into weak links on the linear device performance were studied as well. The LTLSM capabilities and its future potential for non-destructive characterization of the microwave properties of superconducting circuits are discussed

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Section: Basic Principles Of Ltlsm Imagingmentioning

confidence: 99%

Microwave Current Imaging in Passive HTS Components by Low-Temperature Laser Scanning Microscopy (LTLSM)

2006

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“…Since the variation in δP OUT is on the level of HF noise, increased sensitivity is achieved by using ac lock-in detection of the spectrum analyzer signal synchronized to ω M . Figure 1(a) illustrates the method of extraction for the averaged properties from our data [8]. The bolometric LSM PR is modeled here with a shifting of HF transmittance δ||S 21 (f)|| 2 of the CPW resonator by the LSM probe.…”

Section: ⎤ ⎥ ⎥ ⎦mentioning

confidence: 99%

“…Curves Т 1 and Т 2 in Fig. 1(a) Their separate contributions to total LSM PR can be estimated [8] from the resonance line shape is represented by:…”

Section: ⎤ ⎥ ⎥ ⎦mentioning

confidence: 99%

“…The surface of the CPW resonator was scanned by a laser beam (wavelength: 670 nanometers, power 1 mW) focused in an optical probe of 1.2 μm diameter. The intensity of the laser is square-wave modulated by an oscillator with frequency f M = ω M /2π = 100 kHz, raising the average temperature of the sample by ΔT = 0.2 K and creating a thermal probe (of 2l diameter T ) oscillating in the center with magnitude (ΔT/2) cos(ω M t + φ), where φ is the phase shift of the temperature oscillation relative to the square wave modulation [8]. A good acoustic match between the YBCO film and LAO substrate of the device at temperatures above 50 K leads to an l that is defined mainly by the properties of LAO, producing a thermal spot with T l T =(k/cρf M ) 1/2 = 4.8 μm with thermal conductivity k = 9 W/m*K, a specific heat c = 0.58 J/g*K, and density ρ = 6.57 g/cm 3 .…”

Section: ⎤ ⎥ ⎥ ⎦mentioning

confidence: 99%

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Measurement of local reactive and resistive photoresponse of a superconducting microwave device

Zhuravel

Anlage

Ustinov

2006

Applied Physics Letters

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We propose and demonstrate a spatial partition method for the high-frequency photo-response of superconducting devices correlated with inductive and resistive changes in microwave impedance. Using a laser scanning microscope, we show that resistive losses are mainly produced by local defects at microstrip edges and by intergrain weak links in the hightemperature superconducting material. These defects initiate nonlinear high-frequency response due to overcritical current densities and entry of vortices.

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“…[18]). Indeed, quasi-static resonance frequency shift by optical radiation [19,20], or high-energy particles [21] (for which the required condition ξQ ∼ = 1 has been achieved) has been demonstrated.…”

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confidence: 99%

Prospects of employing superconducting stripline resonators for studying the dynamical Casimir effect experimentally

et al. 2007

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We discuss the prospects of employing an NbN superconducting microwave stripline resonator for studying the dynamical Casimir effect experimentally. Preliminary experimental results, in which optical illumination is employed for modulating the resonance frequencies of the resonator, show that such a system is highly promising for this purpose. Moreover, we discuss the undesirable effect of heating which results from the optical illumination, and show that degradation in noise properties can be minimized by employing an appropriate design.PACS numbers: 42.50. Dv, 42.50.Lc, 42.60.Da, 42.60.Fc The term dynamical Casimir effect (DCE) refers usually to the problem of an electromagnetic (EM) cavity with periodically moving walls. The quantum theory of electrodynamics predicts that under appropriate conditions, photons should be created in such a cavity out of the vacuum fluctuations [1]. Such motion-induced radiation is closely related to the Unruh -Davies effect, which predicts that an observer of the EM field in a uniformly accelerating frame would measure thermal radiation with an effective temperature given by a/2πk B c, where a is the acceleration, k B is the Boltzmann's constant, and c is the light velocity in vacuum. Moreover, the equivalence principle of general relativity relates the later effect with the so-called Hawking radiation of black holes [2,3,4,5,6].Efficient production of photons can be achieved by employing parametric resonance conditions [7]. Consider the case where the cavity walls oscillate at twice the resonance frequency of one of the cavity modes (primary parametric resonance). In this case the angular resonance frequency ω r varies in time according toThe system's response to such an excitation depends on the dimensionless parameter ξQ, where Q is the quality factor of the resonator [8]. When ξQ < 1, the system is said to be in the sub-threshold region, while above threshold, when ξQ > 1, the system breaks into oscillations. Achieving the condition ξQ > 1 requires that the shift in the resonance frequency exceeds the width of its peak. So far the DCE has not been verified experimentally [9,10]. It turns out that creation of photons in the case of a cavity with moving walls requires that the peak velocity of the moving walls must be made comparable to light velocity, a task which is extremely difficult experimentally [11]. When this is not the case the system is said to be in the adiabatic regime, where the thermal average number of photons is time independent.An alternative method for realizing the DCE was pointed out by Yablonovitch [12], who proposed that modulating the dielectric properties of a material in an EM cavity might be equivalent to moving its walls. As a particular example, he considered the case of modulating the dielectric constant ǫ of a semiconductor by optical pulses that create electron-hole pairs. The modulation frequency achieved by this method is limited by the recombination time of electron-hole pairs, which can be relatively fast in some semiconductors [13]. Base...

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Frequency modulation of the superconducting parallel-plate microwave resonator by laser irradiation

Cited by 27 publications

References 11 publications

Microwave Current Imaging in Passive HTS Components by Low-Temperature Laser Scanning Microscopy (LTLSM)

Microwave Current Imaging in Passive HTS Components by Low-Temperature Laser Scanning Microscopy (LTLSM)

Measurement of local reactive and resistive photoresponse of a superconducting microwave device

Prospects of employing superconducting stripline resonators for studying the dynamical Casimir effect experimentally

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