Ultrafast Response Induced by Interference Effects between Weakly Confined Exciton States

Kojima, Osamu; Isu, Toshiro; Ishi‐Hayase, Junko; Kanno, Atsushi; Katouf, Redouane; Sasaki, Masahide; Tsuchiya, Masahiro

doi:10.1143/jpsj.77.044701

Cited by 26 publications

(43 citation statements)

References 14 publications

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“…On the other hand, the scattering spectra of the thin film are significantly modified from the bulk ones, and we found that they reflect the exciton-photon coupled modes in the thin film. 17,18,21,33,35 Therefore, the RHPS measurement is also useful to observe the exciton-photon coupled modes in nano-structured materials 34 as well as the four-wave mixing 17,29,35 and the two-photon excitation scattering. 33 We also found that semiconductor thin films have much degrees of freedom to control generated states of entangled photon pairs.…”

Section: Discussionmentioning

confidence: 99%

“…11,50-52 Moreover, optical responses explicitly reflects the confinement of center-of-mass motion of excitons in nano-structured materials and also in the nanoto-bulk crossover regime, [17][18][19][20][26][27][28][29][30][31][32][33][34][35][36] which we investigate in the present paper.…”

Section: 43mentioning

confidence: 99%

“…(45) and (47) reproduces Eq. (35). By using the output fieldĚ + 0,OUT (r, ω) in the background system, we define the scattering field excluding the input one asĚ…”

Section: E Green's Function Techniquementioning

confidence: 99%

“…Actually, owing to the recent development of nanoscale fabrication, anomalous nonlinear optical processes have been reported in semiconductor nano-structures and in the nano-to-bulk crossover regime. 17,[26][27][28][29][30][31][32][33][34][35][36] Further, it shows a rapid radiative decay rate of excitons on the order of 100 fs due to the exciton superradiance.…”

mentioning

confidence: 99%

“…The peak positions are different for H-and V-polarizations, and they do not obey the angle-frequency relation for bulk crystal. 37 The spectral shape can be interpreted by the exciton-photon coupled modes 17,18,21,32,33,35 in the thin film, which have been discussed in relation with the radiative decay of excitons in nano-to-bulk crossover regime. [22][23][24][25] Due to the breaking of translational symmetry in z direction, the lower and upper polaritons in bulk material are no longer good eigen states, but instead we obtain the excitonphoton coupled modes with discrete energy levels and radiative decay rates in the case of thin films.…”

mentioning

confidence: 99%

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Generation of entangled-photon pairs from biexcitons in CuCl thin films: Nano-to-bulk crossover regime

Bamba¹,

Ishihara²

2011

Phys. Rev. B

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We have constructed a theoretical framework of the biexciton-resonant hyperparametric scattering for the pursuit of high-power and high-quality generation of entangled photon pairs. Our framework is applicable to nano-to-bulk crossover regime where the center-of-mass motion of excitons and biexcitons is confined. Material surroundings and the polarization correlation of generated photons can be considered. We have analyzed the entangled-photon generation from CuCl film, by which ultraviolet entangled-photon pairs are generated, and from dielectric microcavity embedding a CuCl layer. We have revealed that in the nano-to-bulk crossover regime we generally get a high performance from the viewpoint of statistical accuracy, and the generation efficiency can be enhanced by the optical cavity with maintaining the high performance. The nano-to-bulk crossover regime has a variety of degrees of freedom to tune the entangled-photon generation, and the scattering spectra explicitly reflect quantized exciton-photon coupled modes in the finite structure.

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Section: Discussionmentioning

confidence: 99%

Section: 43mentioning

confidence: 99%

“…(45) and (47) reproduces Eq. (35). By using the output fieldĚ + 0,OUT (r, ω) in the background system, we define the scattering field excluding the input one asĚ…”

Section: E Green's Function Techniquementioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Generation of entangled-photon pairs from biexcitons in CuCl thin films: Nano-to-bulk crossover regime

Bamba¹,

Ishihara²

2011

Phys. Rev. B

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Transient reflectivity response with negative time delay caused by femtosecond pulse propagation in GaAs thin films

Watanabe

Kojima

Wada

et al. 2009

Phys. Status Solidi (c)

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We have investigated the propagation effects on the transient response of confined excitons in GaAs thin films by a reflection‐type pump‐probe technique. The spectrally integrated signal demonstrated slower rise than the pulse width in the negative time region. Moreover, reflectivity change spectra indicate that the response in the negative time region originates from the effect of the confined excitons and that the signal rise time at each exciton state is different. The propagation velocities estimated from the rise times and the film thickness correspond to the group velocities of the exciton polariton in bulk crystals. Therefore, the origin of the responses in the negative time region is the pulse modulation caused by the propagation effect of exciton polariton. In addition, it was confirmed that this propagation disappears with an increase in temperature due to the spatial decoherence of excitons. These results demonstrate that the propagation effect of exciton polariton on optical response in femtosecond time scale has a considerable influence in the realization of ultrafast optical devices. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Optical Kerr response to multi pump pulses on GaAs weakly confined exciton

Kanno

Katouf

Kojima

et al. 2009

Phys. Status Solidi (c)

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We investigate optical Kerr response under two‐pump pulse irradiation induced by GaAs weakly confined exciton. Ultrafast response times of the order of picoseconds are observed despite long exciton lifetime of the order of nanoseconds. The difference may be attributed to the relaxation mechanisms between population relaxation and nonlinear relaxation of excitons. In addition, the observed temporal shapes of the optical Kerr response are conserved under irradiation by a preceding pulse that forms the exciton population. The pulse separation of the optical Kerr response between two pump pulses is achieved to be 800 fs, which corresponds to a signal train of 1.25 Tbits per second. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Ultrafast Response Induced by Interference Effects between Weakly Confined Exciton States

Cited by 26 publications

References 14 publications

Generation of entangled-photon pairs from biexcitons in CuCl thin films: Nano-to-bulk crossover regime

Generation of entangled-photon pairs from biexcitons in CuCl thin films: Nano-to-bulk crossover regime

Transient reflectivity response with negative time delay caused by femtosecond pulse propagation in GaAs thin films

Optical Kerr response to multi pump pulses on GaAs weakly confined exciton

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