Detailed analysis of second-harmonic generation near 10.6 μm in GaAs/AlGaAs asymmetric quantum wells

Boucaud, P.; Julien, F. H.; Yang, Darang; Lourtioz, J.‐M.; Rosencher, E.; Bois, P.; Nagle, J.

doi:10.1063/1.103742

Cited by 108 publications

(35 citation statements)

References 12 publications

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“…Experiments confirm that significant second-harmonic conversion takes place in such structures 26,27 and that the harmonic process is based on intersubband resonance enhancement 27. A record value of the second-order susceptibility associated with SHG is found, about 1900 times larger than in bulk GaAs 27.…”

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confidence: 60%

Second-Harmonic Generation in Asymmetric AlGaAs Quantum Wells

Julien

1992

NATO ASI Series

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Optical transitions between conduction subbands of GaAs-AIGaAs quantum wells are of considerable interest for mid-infrared (MIR, applications due to their very large oscillator strengths 1. Indeed, the dipole moments associated with intersubband transitions only involve matrix elements between envelope wave functions which translate into effective dipole lengths scaling like the quantum well thickness 2. For comparison, the dipole length associated with an interband transition would be much shorter, of the order of the lattice constant because the matrix elements involve the periodic part of the Bloch wavefunctions. This large value of the intersubband dipole moments offers the basis for efficient linear and non-linear optical interaction schemes as long as the ground conduction subband of the quantum well is populated. This is usually achieved by means of epitaxial n-doping of the quantum well heterostructure. Photodetectors 3 and optical Stark-shifted modulators 4 based on a linear intersubband absorption process in n-doped quantum wells have been investigated first. The work on photodetection has considerably evolved since then with the demonstration of high quantum efficiencies under polarized irradiation for photodetectors operating in the photoconductive, 5-7 photovoltaic 8,9 or photon-drag 10,11 regime. Recently, photoinduced intersubband absorption in undoped GaAs-AIGaAs mUlti-quantum wells (MQW) was reported by several authors 12-14 with special emphasis on intersubband-interband spectroscopy of the quantum wells 14 and on all-optical modulation of MIR radiations 15. Intersubband emissions from GaAs/AIGaAs superlattices using either parallel or perpendicular electronic transport have been demonstrated 16,17.The intersubband resonance enhancement of optical non-linearities have also been investigated. Efficient second-order non-linearities based on intersubband resonance enhancement were first predicted by Gurnick and De Temple in 1983 18. Because in a centro-symmetric system the second-order susceptibilities vanish 19, the authors have considered quantum well heterostructures whose conduction band profile reproduces a Morse well potential. Huge increases in the second-order susceptibilities associated with second-harmonic generation (SHG) and optical rectification were predicted. The first experimental evidence of an intersubband-resonance enhancement of the second-harmonic generation was obtained by Fejer et a1 20 using an applied electric field to break the symmetry of the envelope wavefunctions. Previously, this dc-biased situation had been theoretically studied by Ikonic et al 21. However, larger second-order susceptibilities Intersubband Transitions in Quantum WellsEdited by E. Rosencher et al., Plenum Press, New York, 1992

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confidence: 60%

Second-Harmonic Generation in Asymmetric AlGaAs Quantum Wells

Julien

1992

NATO ASI Series

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“…Recently, some research effort has been put into finding the best potential shape of continuously graded QWs [13][14][15][16]. However, most of the papers published so far describe resonant SHG for the pump photon energy value of~ω = 116 meV, which corresponds to CO 2 laser input [3][4][5][6][7][8][9][10][11][12][13][14][15][16] or even larger wavelengths [17]. The reason is that for this pump photon energy it is relatively straightforward to achieve conditions necessary for SHG in common GaAs/Al x Ga 1−x As-based QWs.…”

Section: Introductionmentioning

confidence: 99%

“…It was a common practice to take all three states needed for SHG to be bound, and various QWs were analyzed for this case, e.g. compositionally graded, in a stepwise-constant manner, step QWs [3][4][5][6][7], electric-field-biased QWs [8,9] and asymmetric-coupled QWs [10][11][12]. Recently, some research effort has been put into finding the best potential shape of continuously graded QWs [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Supersymmetric quantum-well shape optimization for intersubband bound–continuum second harmonic generation

Indjin

Stanković

Radovanović

et al. 2000

Superlattices and Microstructures

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“…4,5 The core of these structures consists of asymmetric coupled double quantum wells ͑ACQW͒ with three tunable levels positioned to achieve population inversion and MIR or FIR emission. 1,2 The operation of such ACQW structures is critically dependent on the lifetime of each energy level, which in turn is strongly influenced by electron-polar optical phonon ͑POP͒ interaction.…”

Section: Introductionmentioning

confidence: 99%

Phonon dispersion and electron–polar optical phonon interaction in coupled quantum-well structures in the modified image–charge ansatz approach

Wang

Leburton

Požela³

1997

Journal of Applied Physics

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Phonon dispersion and Fröhlich interaction in coupled quantum-well structures are derived by using a modified image–charge ansatz that shows that the mode symmetry in the surface phonon dispersion of single quantum-well (QW) structures is modified by the addition of a thin inner barrier. The electron–phonon scattering rates are evaluated for phonons in the entire coupled QW configuration and compared with the corresponding rates calculated for phonons in the separated-single QW approximation. Our calculations show that the separated-single QW phonon model provides reasonable estimates of the electron–phonon scattering rates except for intersubband processes when the quantized energy separation between the initial and final electron states is in resonance with the polar optical phonon energy.

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Detailed analysis of second-harmonic generation near 10.6 μm in GaAs/AlGaAs asymmetric quantum wells

Cited by 108 publications

References 12 publications

Second-Harmonic Generation in Asymmetric AlGaAs Quantum Wells

Second-Harmonic Generation in Asymmetric AlGaAs Quantum Wells

Supersymmetric quantum-well shape optimization for intersubband bound–continuum second harmonic generation

Phonon dispersion and electron–polar optical phonon interaction in coupled quantum-well structures in the modified image–charge ansatz approach

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