Two-photon absorption in GaN, GaInN, and GaAlN alloys

Krishnamurthy, Srinivasan; Nashold, Karen; Sher, A.

doi:10.1063/1.126974

Cited by 30 publications

(18 citation statements)

References 12 publications

(18 reference statements)

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“…1 Recently, the optical nonlinearities of these materials have attracted increased interest as factors for determining device performance. [2][3][4][5][6][7][8][9][10][11] In addition to the technological importance, these nonlinear absorption studies also provide important insights into the fundamental physics of materials, such as band structures, 6 relaxation processes, [7][8][9][10] and electron-phonon interactions. 11 One characteristic of GaN observed in photoluminescence ͑PL͒ spectra is yellow luminescence ͑YL͒.…”

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confidence: 99%

Two-photon absorption and multiphoton-induced photoluminescence of bulk GaN excited below the middle of the band gap

Toda

Matsubara

Morita

et al. 2003

Applied Physics Letters

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Optical nonlinearity in the yellow luminescence (YL) band of GaN was investigated using thick bulk samples. Transient pump–probe measurements revealed strong transmission changes due to two-photon absorption(TPA) even at the middle of the YL band. The TPA coefficient evaluated reaches ∼5 cm/GW∼5 cm/GW at about 1.3 eV, which was as large as the mid-gap resonance. The TPA spectrum clearly showed that the observed large nonlinearity originated from the YL band. On the basis of efficient TPA in the YL band, relaxation processes in the multiphoton-induced photoluminescence excitation spectrum were also investigated

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confidence: 99%

Two-photon absorption and multiphoton-induced photoluminescence of bulk GaN excited below the middle of the band gap

Toda

Matsubara

Morita

et al. 2003

Applied Physics Letters

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“…This can be qualitatively interpreted as the photon energy increases from Eig/2 to nearly Eig, the electrons excited from the valance band find an increasing availability of conduction band states. A similar tendency is observed in directed band semiconductor TPA, such as GaN and GaInN [7] .…”

Section: Resultsmentioning

confidence: 49%

The dispersion dependence of nonlinear optical absorption transition in silicon PIN photodiode

Cui

Qian

et al. 2013

2013 13th International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD)

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Abstract-This paper presents an experimental study on the dispersion dependence of two-photon absorption (TPA) between 0.689~0.912 eV in a Si-base PIN photodiode. The obvious TPA process is clearly observed as the nonlinear enhancement of peak photoresponse on the incident light intensity in the power of 2. The tendency of the TPA coefficient increases with the incident photon energy increasing. The maximum enhancement factor of the TPA coefficient has been achieved as high as 4 times. This dispersion dependence of TPA has been qualitatively interpreted as when the photon energy increases, the electrons of valance band excited by TPA find an increasing availability states of conduction band by phonon assistance.

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“…On the other hand, increasing the laser intensity increases dn/dE g until the point where the two-photon absorption dominates. The two-photon absorption is almost independent of the detuning near the band edge [24] . Hence its domination suppresses the Coulomb cooling process.…”

Section: -Results and Discussionmentioning

confidence: 99%

“…We also note that C stark for our current MQW design is approximately equal to 1.2×10 -28 • as confirmed by the Poisson-Schrodinger solver, the mass density is 6.15 g/cm 3 , lattice constant is 3.24 Å, ≈ 6.5 × 10 F/m (for GaN at the wavelength of 0.4 μm), ≈ 1 nm, and the Coulomb strength parameter is ≈ 1.4×10 -19 Vm 2 . We have used the two-photon absorption coefficient spectra for a similar structure reported by Krishnamurthy et al [24].…”

Section: -Simulationmentioning

confidence: 99%

Exploring Coulomb interaction in piezoelectric materials for assisting the laser cooling of solids

Nia¹,

Mohseni²

2014

SPIE Proceedings

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Realization of anti-Stokes cooling requires high enough photon extraction efficiency as well as quantum efficiency, making the implementation of this technique extremely difficult for semiconductors. Here, for the first time, we demonstrate that the Coulomb interaction between photogenerated electron-hole pairs in strong piezoelectric materials such as GaN/InGaN quantum wells could assist laser cooling. By comparing to the cavity back-action mechanism, we also explain how this process depends upon laser detuning with respect to bandgap. To demonstrate the advantage of this method even further, we present simulations by using experimentally reported parameters of GaN and In 0.15 Ga 0.85 N, in order to conclude that the net cooling is indeed possible even with current III-nitride growth technology. 1-INTRODUCTIONAnti-Stokes phenomenon has been investigated extensively for achieving the laser cooling of solids [1][2][3][4]. This process is based on extraction of the phonon energy by means of photo luminance (PL). The photogenerated electron hole pairs gain energy from the phonon bath and consequently release the energy upon recombination. In this regard, if the radiative recombination dominates all the other processes and the emitted PL can get out of the medium (see Ref[5] as an example of increasing the extraction efficiency), then anti-Stokes laser cooling will be possible. The first laser cooling of a solid (ytterbium doped glass) was achieved in 1995 by Epstein et al [4]. However, for semiconductors, due to strict quantum efficiency requirements and lower extraction efficiencies, this goal couldn't be achieved until recently when Zhang et al [6] showed anti stokes refrigeration in CdS nano-belts. It should be noted that there have been numerous attempts to increase the quantum efficiency of III-V semiconductors. This trend also led to growth of semiconductors which can have potential use for laser cooling applications [7]. As for the case of enhancing the extraction efficiency, some novel techniques have been proposed such as attaching a dome lens to the semiconductor[7], using surface plasmon polaritons[8], Mie scattering [5],evanescent coupling through a nano-gap [3], and surface roughening [9].Another technique of laser cooling, known as optomechanical backaction, can be implemented when the optical and mechanical modes of a cavity are coupled effectively [10]. In this case, cooling -or amplification of the mechanical mode depends on laser detuning. Metzger et al [11] showed the utilization of this method for cooling a gold coated silicon membrane. The drawback of this method is the involvement of only one vibration mode of the cavity which reduces its effectiveness when dealing with a phonon bath in a solid.

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Two-photon absorption in GaN, GaInN, and GaAlN alloys

Cited by 30 publications

References 12 publications

Two-photon absorption and multiphoton-induced photoluminescence of bulk GaN excited below the middle of the band gap

Two-photon absorption and multiphoton-induced photoluminescence of bulk GaN excited below the middle of the band gap

The dispersion dependence of nonlinear optical absorption transition in silicon PIN photodiode

Exploring Coulomb interaction in piezoelectric materials for assisting the laser cooling of solids

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