Spatial Optical Parametric Coupling of Picosecond Light Pulses and Transverse Relaxation Effect in Resonant Media

Yajima, Tatsuo; Taira, Yoichi

doi:10.1143/jpsj.47.1620

Cited by 471 publications

(162 citation statements)

References 8 publications

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“…The peak position of such a FWM signal versus interpulse delay occurs after τ = 0 by an amount determined by the degree of inhomogeneous broadening and the dephasing time (T 2 ) such that larger values of T 2 lead to a later signal peak. 41 Our observation of a shift in the interband continuum response to larger delay values in LT-GaAs between the results for the as-grown sample, and the samples annealed at 400 • C and 500 • C reflects an annealing-induced increase of the interband dephasing time. Since the density of As i and As Ga point defects and/or defect complexes is reduced with annealing, our results indicate that these defects play a role in free carrier dephasing in weakly-annealed LT-GaAs for the conditions considered here (80 K, 1 ×10 16 cm 3 ).…”

Section: Aip Advances 8 045121 (2018)mentioning

confidence: 61%

Control of the Urbach band tail and interband dephasing time with post-growth annealing in low-temperature-grown GaAs

et al. 2018

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Section: Aip Advances 8 045121 (2018)mentioning

confidence: 61%

Control of the Urbach band tail and interband dephasing time with post-growth annealing in low-temperature-grown GaAs

et al. 2018

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“…A slice of the two-dimensional SR-FWM data in Figure 2(b) is shown in Figure 3(a) for a fixed photon energy of 1.533 eV, illustrating the dependence of the signal on the delay between the excitation pulses. This delay-dependent signal may be fit using an analytic model 33 convoluted with the finite laser pulse profile (measured using zero-background autocorrelation techniques), allowing the dephasing time for electron-hole pairs to be extracted (T2 = 65 fsec for the data shown). These fits are indicated by the solid curves in Figure 3.…”

Section: Representative Resultsmentioning

confidence: 99%

Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing

Webber

Boer

Yıldırım

et al. 2013

JoVE

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The application of femtosecond four-wave mixing to the study of fundamental properties of diluted magnetic semiconductors ((s,p)-d hybridization, spin-flip scattering) is described, using experiments on GaMnAs as a prototype III-Mn-V system. Spectrally-resolved and timeresolved experimental configurations are described, including the use of zero-background autocorrelation techniques for pulse optimization. The etching process used to prepare GaMnAs samples for four-wave mixing experiments is also highlighted. The high temporal resolution of this technique, afforded by the use of short (20 fsec) optical pulses, permits the rapid spin-flip scattering process in this system to be studied directly in the time domain, providing new insight into the strong exchange coupling responsible for carrier-mediated ferromagnetism. We also show that spectral resolution of the four-wave mixing signal allows one to extract clear signatures of (s,p)-d hybridization in this system, unlike linear spectroscopy techniques. This increased sensitivity is due to the nonlinearity of the technique, which suppresses defect-related contributions to the optical response. This method may be used to measure the time scale for coherence decay (tied to the fastest scattering processes) in a wide variety of semiconductor systems of interest for next generation electronics and optoelectronics.

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“…It is assumed that T 31 =T 32 =T phase , where the phase relaxation time T phase of a free charge carrier is quite short (about 100fs) compared to that of E-H pairs in the bulk of QWs in low temperatures, which is about few picoseconds. Timedomain coherent optical experiments show a big range for T phase [28][29][30][31][32][33]. Strongly interacting E-H pairs excited to high densities by band-to-band transitions show T phase of the order of a few 100fs [24].…”

Section: A Quantum Wellmentioning

confidence: 99%

Optical Modulation by Conducting Interfaces

Karimi

Khorasani

2013

IEEE J. Quantum Electron.

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Abstract-We analyze the interaction of a propagating guided electromagnetic wave with a quantum well embedded in a dielectric slab waveguide. First, we design a quantum well based on InAlGaAs compounds with the transition energy of 0.8eV corresponding to a wavelength of 1.55m. By exploiting the envelope function approximation, we derive the eigenstates of electrons and holes and the transition dipole moments, through solution of the Luttinger Hamiltonian. Next, we calculate the electrical susceptibility of a threelevel quantum system (as a model for the two-dimensional electron gas trapped in the waveguide), by using phenomenological optical Bloch equations. We show that the two-dimensional electron gas behaves as a conducting interface, whose conductivity can be modified by controlling the populations of electrons and holes the energy levels. Finally, we design a slab waveguide in which a guided wave with the wavelength of 1.55m experiences a strong coupling to the conducting interface. We calculate the propagation constant of the wave in the waveguide subject to the conducting interface, by exploiting the modified transfer matrix method, and establish it linear dependence on the interface conductivity. By presenting a method for controlling the populations of electrons and holes, we design a compact optical modulator with an overall length of around 60m. Most of these applications are realized using physical phenomena such as electrooptic, thermooptic, or magnetooptic effects to allow control over the propagation and transmission of optical wavefronts. Modulation speeds in excess of 50GHz have so far been achieved in the basic Mach-Zhender Modulator (MZM) configuration. While MZM could utilize virtually any physical effect to allow optical modulation, normally the linear electrooptic effect in bulk semiconductors is used. High speed modulation is also possible using internal modulation schemes, for instance, by direct current modulation [6,7]. However, most wideband applications require external modulation of light. A common material which is widely used in this area is LiNbO 3 . But there is a drawback in using MZMs as external modulators is that they normally require very long propagation lengths of the order of a few millimeters. This requirement makes the MZMs highly inappropriate for integrated fabrication. There is also another problem with routine material platforms, which happen to be incompatible with the standard III/V compound semiconductor technology. Index Terms-Hence, one should look for an alternative physical phenomenon other than the above, which would enable strong modulation, ease of fabrication, compatibility with III/V optoelectronics integration, linear response, tunability, and possibility of modern quantum optical applications including quantum information processing and cavity quantum electrodynamics.More than a decade ago, we coined the term Conducting Interface to a family of optoelectronic devices, in which the electrooptic effect is maintained by a surface accumulation or deplet...

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Spatial Optical Parametric Coupling of Picosecond Light Pulses and Transverse Relaxation Effect in Resonant Media

Cited by 471 publications

References 8 publications

Control of the Urbach band tail and interband dephasing time with post-growth annealing in low-temperature-grown GaAs

Control of the Urbach band tail and interband dephasing time with post-growth annealing in low-temperature-grown GaAs

Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing

Optical Modulation by Conducting Interfaces

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