Nonlocal Photorefractive Screening from Hot Electron Velocity Saturation in Semiconductors

Brubaker, R. M.; Wang, Q. N.; Nolte, David D.; Melloch, M. R.

doi:10.1103/physrevlett.77.4249

Cited by 28 publications

(17 citation statements)

References 16 publications

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“…Photorefractive phase shifts were discovered in transverse-field photorefractive quantum wells 15 and have been shown to arise from hot-electron effects and transport nonlinearity. 10,16 In Eq. (8) the modulation amplitude is given by the index m multiplied by a parameter , which expresses the contrast ratio of the field within the device relative to the modulation expressed by Eq.…”

Section: A Associating Photorefractive Gratings With Electroabsorptionmentioning

confidence: 99%

“…The two-wave mixing performance in the quantum wells is complicated by several aspects of the device operation that have not previously been explored in detail. These aspects include the deviation from quadratic dependence of the electroabsorption at high electric fields, the onset of hot-electron effects associated with the Gunn effect in GaAs, 10 and the role of the excitonic spectral phase in achieving quadrature. We provide a complete experimental exploration of these effects and apply the results to predict the noise-equivalent surface displacement (NESD) for laser-based ultrasound detection using photorefractive quantum-well devices.…”

Section: Introductionmentioning

confidence: 99%

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Adaptive beam combining and interferometry with photorefractive quantum wells

et al. 2001

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We present a comprehensive study of excitonic electroabsorption and two-wave mixing in photorefractive quantum wells. By combining these two measurements, we are able to determine the internal grating writing efficiency for converting an external spatial light modulation into an internal space-charge field. The internal writing efficiency at a fringe spacing ⌳ ϭ 40 m is found to be a decreasing function of applied field, varying from ϭ 0.4 at low fields to 0.2 at 12 kV/cm. The two-wave mixing efficiency in the quantum wells exceeds 40% and is used for adaptive beam combining and laser-based ultrasound detection. The quantum wells balance the hot-electron-induced photorefractive phase shift with excitonic spectral phase to guarantee quadrature in homodyne detection of ultrasound-induced surface displacements. The ability to tune through multiple quadratures is demonstrated here for the first time to our knowledge. We derive a noise-equivalent surface displacement of 1.7 ϫ 10 Ϫ6 Å (W/Hz) 1/2 at a field of 12 kV/cm and a fringe spacing of ⌳ ϭ 40 m. This value is within a factor of 7 of the shot-noise limit of an ideal interferometer.

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Section: A Associating Photorefractive Gratings With Electroabsorptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Adaptive beam combining and interferometry with photorefractive quantum wells

et al. 2001

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“…This phenomenon leading to the decrease of the electron mobility is the reason of Gunn oscillations in doped GaAs crystals. Although, due to low free carriers concentrations, Gunn oscillations do not appear in semi-insulating MQW 6 , the nonlinear transport due to the field dependent mobility of electrons change the photorefractive effect 6,7 .…”

Section: Introductionmentioning

confidence: 97%

The influence of nonlinear electron transport on photorefractive properties of semi-insulating multiple quantum well structure

Weinert-Rączka¹,

Wichtowski²

2005

SPIE Proceedings

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Stationary and transient behaviour of photorefractive multiple quantum well structure illuminated by interfering plane waves of near resonant frequency was investigated in frames of photogeneration, diffusion, drift and trapping (PDDT) model. The influence of high intensity electric field applied along the quantum wells planes was considered and an effect of a nonlinear transport of electrons, characteristic for GaAs/AlGaAs samples, was included. An analytical expression for the fundamental amplitude of space-charge field in the sample and the dependence of the photorefractive grating response time on material parameters in the case of low interference pattern contrast is presented and compared with the earlier results.

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“…neglecting a common overall absorption of the beams in the PRQW, where P l 0 and P p 0 are the probe and local oscillator power before the PRQW, ͑t͒ is the phase modulation, and P is the photorefractive phase shift that represents the phase offset between the intensity pattern and the optical index pattern driven by the space-charge formation [15,16]. The excitonic spectral phase ͑͒ is defined by…”

Section: Intensity-free Homodyne Detection Using Photorefractive Quanmentioning

confidence: 99%

“…where T 2 is the excitonic free induction decay (FID) time [16]. Because of the wavelength dependence of ͑͒, the quadrature condition [17] is achieved by selecting the operating frequency q at which ͑͒ ϩ P ϭ 0 or , and the homodyne signals depend linearly on the phase modulation.…”

Section: Intensity-free Homodyne Detection Using Photorefractive Quanmentioning

confidence: 99%

Adaptive interferometry of protein on a BioCD

et al. 2007

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Adaptive spinning-disk interferometry is capable of measuring surface profiles of a thin biolayer with subnanometer longitudinal resolution. High-speed phase modulation in the signal beam arises from the moving surface height profile on the spinning disk and is detected as a homodyne signal via dynamic two-wave mixing. A photorefractive quantum-well device performs as an adaptive mixer that compensates disk wobble and vibration while it phase-locks the signal and reference waves in the phase quadrature condition (͞2 relative phase between the signal and local oscillator). We performed biosensing of immobilized monolayers of antibodies on the disk in both transmission and reflection detection modes. Single-and dual-analyte adaptive spinning-disk immunoassays were demonstrated with good specificity and without observable cross-reactivity. Reflection-mode detection enhances the biosensing sensitivity to one-twentieth of a protein monolayer, creates a topographic map of the protein layer, and can differentiate monolayers of different species by their effective optical thicknesses.

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Nonlocal Photorefractive Screening from Hot Electron Velocity Saturation in Semiconductors

Cited by 28 publications

References 16 publications

Adaptive beam combining and interferometry with photorefractive quantum wells

Adaptive beam combining and interferometry with photorefractive quantum wells

The influence of nonlinear electron transport on photorefractive properties of semi-insulating multiple quantum well structure

Adaptive interferometry of protein on a BioCD

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