Ultrafast intersubband relaxation and nonlinear susceptibility at 1.55 μm in GaN/AlN multiple-quantum wells

Hamazaki, Junichi; Matsui, Satoshi; Kunugita, Hideyuki; Ema, Kazuhiro; Kanazawa, Hitoshi; Tachibana, T.; Kikuchi, Akihiko; Kishino, Katsumi

doi:10.1063/1.1647275

Cited by 89 publications

(54 citation statements)

References 8 publications

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“…The III-nitride-based ISBT has two important properties suited for next-generation optoelectronic devices: ultrafast carrier relaxation speed compared with other ISBT materials and nontoxicity. For example, an ultrahigh-speed carrier relaxation time of 140 fs was observed in GaN/AlN ISBT [4].…”

Section: Introductionmentioning

confidence: 99%

Room temperature operation of 1.55.MU.m wavelength-range GaN/AlN quantum well intersubband photodetectors

Uchida

Matsui

Holmström

et al. 2005

IEICE Electron. Express

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Abstract:The room-temperature operation of a GaN/AlN quantum well infrared photodetector (QWIP) using the intersubband transition (ISBT) in a GaN/AlN multiple quantum well (MQW) was demonstrated for the first time. The GaN/AlN QWIP was operated under DC biasing with a vertically conductive geometry to the MQW layer. A clear photoinduced response was observed for P polarized 1.47 µm light irradiation. Dependencies of the photoresponse on the applied DC bias voltage, and the polarization and wavelength of incident light were evaluated for the GaN/AlN QWIP. The maximum responsivity was estimated to be 0.11 mA/W for a DC bias of 15 V at room temperature. Keywords: GaN/AlN, intersubband, quantum well, photodetector, optical communication wavelength, nitride Classification: Photonics devices, circuits, and systems Tachibana, A. Kikuchi, and K. Kishino, "Ultrafast intersubband relaxation and nonlinear susceptibility at 1.55 µm in GaN/AlN multiplequantum wells," Appl. References

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Section: Introductionmentioning

confidence: 99%

Room temperature operation of 1.55.MU.m wavelength-range GaN/AlN quantum well intersubband photodetectors

Uchida

Matsui

Holmström

et al. 2005

IEICE Electron. Express

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“…Because they have large conduction band discontinuities and thus allow IS transitions at short wavelengths, GaN=AlGaN multiple quantum wells have received much interest. Intersubband absorption in such quantum wells has been observed in the spectral range up to the telecommunication wavelength of 1:55 m [17][18][19]. Recently, IS absorption was also observed in GaN=AlGaN-based high-electron-mobility transistors [20].…”

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confidence: 99%

Optical Phonon Sidebands of Electronic Intersubband Absorption in Strongly Polar Semiconductor Heterostructures

et al. 2005

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We present the first evidence for a distinct optical phonon progression in the linear and nonlinear intersubband absorption spectra of electrons in a GaN=Al 0:8 Ga 0:2 N heterostructure. Femtosecond twocolor pump-probe experiments in the midinfrared reveal spectral holes on different vibronic transitions separated by the LO-phonon frequency. These features wash out with a decay time of 80 fs due to spectral diffusion. The remaining nonlinear transmission changes decay with a time constant of 380 fs. All results observed are described by the independent boson model.The optical line shapes of electronic transitions in condensed matter reflect the ultrafast dynamics of the elementary excitations to which the electrons are coupled. Of particular interest for a broad range of phenomena is the coupling between electrons and nuclear motions, i.e., local vibrational modes and/or phonons.(i) Coupling to underdamped nuclear motions gives rise to spectrally distinct sidebands in electronic spectra [1]. In molecules, such an interaction with intramolecular modes underlies the vibronic structure of electronic absorption and emission bands, which are additionally broadened by dephasing and spectral diffusion processes originating from a coupling to (overdamped) motions of the fluctuating surroundings [2,3]. In crystalline solids with much more delocalized electronic wave functions and phonon modes, phonon sidebands of electronic transitions have been observed mainly for interband spectra of impurities [1], for quantum-dot-like structures [4][5][6][7][8], and through coherent phonon oscillations modulating the optical reflectivity [9,10].(ii) Electron-phonon coupling strongly influences the nonequilibrium dynamics of electrons, both in the quantum-kinetic [11] and in the incoherent scattering regimes [12]. Such phenomena occur on femtosecond to picosecond time scales and have been investigated extensively by ultrafast nonlinear spectroscopy.So far, the majority of investigations of electron-phonon coupling focused on interband transitions in solids. The influence of electron-phonon coupling on intraband transitions was mainly studied in the context of polaron physics [13,14]. Intraband transitions provide direct access to the nonequilibrium dynamics of electrons. Theoretical studies suggest a prominent role of electron-phonon coupling for the line shape of intraband (free-carrier) absorption and emission. So far, clear experimental signatures of electron-phonon coupling are missing for the line shape of intersubband (IS) transitions (dipole-allowed transitions between quantized conduction subbands [15]), although first theoretical studies predict such polaronic signatures [16].Because of their strong electron-phonon coupling, nanostructures made from strongly polar materials like group-III nitrides are promising systems for the occurrence of IS phonon sidebands. Because they have large conduction band discontinuities and thus allow IS transitions at short wavelengths, GaN=AlGaN multiple quantum wells have received much interes...

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“…[63] ). We now consider a practical scenario with two equal-intensity pump waves with power density I p 1 = I p 2 = 50 MW/cm 2 [73,74] , and realistic silver losses at ω /2 π = 320 THz. Figure 8 A shows the corresponding image plane fi eld distribution at x = 3 d /2, for a sub-wavelength source placed at x = -d /2.…”

Section: Phase Conjugation and Time Reversalmentioning

confidence: 99%

Enhanced nonlinearities using plasmonic nanoantennas

2012

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In this paper, we review and discuss how nanoantennas may be used to largely enhance the nonlinear response of optical materials. For single nanoantennas, there have been tremendous advancements in understanding how to exploit the local fi eld enhancement to boost the nonlinear susceptibility at the surface or sharp edges of plasmonic metals. After an overview of the work in this area, we discuss the possibility of controlling the optical nonlinear response using nanocircuit concepts and of signifi cantly enhancing various nonlinear optical processes using planar arrays of plasmonic nanoantennas loaded with χ (2) or χ (3) nonlinear optical materials, forming ultrathin, nanometer-scale nonlinear metasurfaces, as optical nanodevices. We describe how this concept may be used to boost the effi ciency of nonlinear wave mixing and optical bistability, due to the large local fi eld enhancement at the nonlinear nanoloads associated with the plasmonic features of suitably tailored nanoantenna designs. We fi nally discuss three exciting applications of the proposed nonlinear metasurface: dramatically-enhanced frequency conversion effi ciency, effi cient phase-conjugation for super-resolution imaging and large optical bistabilities.

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Ultrafast intersubband relaxation and nonlinear susceptibility at 1.55 μm in GaN/AlN multiple-quantum wells

Cited by 89 publications

References 8 publications

Room temperature operation of 1.55.MU.m wavelength-range GaN/AlN quantum well intersubband photodetectors

Room temperature operation of 1.55.MU.m wavelength-range GaN/AlN quantum well intersubband photodetectors

Optical Phonon Sidebands of Electronic Intersubband Absorption in Strongly Polar Semiconductor Heterostructures

Enhanced nonlinearities using plasmonic nanoantennas

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