Spectral and temperature dependence of two-photon and free-carrier absorption in InSb

Olszak, Peter D.; Cirloganu, Claudiu M.; Webster, Scott; Padilha, Lázaro A.; Guha, Shekhar; Gonzalez, Leonel P.; Krishnamurthy, Srini; Hagan, David J.; Stryland, Eric W. Van

doi:10.1103/physrevb.82.235207

Cited by 25 publications

(15 citation statements)

References 29 publications

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“…In fact, exciton enhancement should be considered in the theoretical calculation of TPA coefficients. For the 3.0 nm dots in the resonant regime, the discrepancy may be due to the exciton enhancement near the band gap, similar to the analysis of ZnTe, InSb . The density of exciton states will become larger when the photon energy of the excitation laser beam gets closer to the band gap of the CQD.…”

Section: Resultsmentioning

confidence: 69%

Ultrafast Saturable Absorption of Core/Shell Colloidal Quantum Dots

Zhang

Dong

et al. 2016

Part. Part. Syst. Charact.

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Ultrafast saturable absorption (SA) materials that are capable of blocking the optical absorption under strong excitation have extensive applications in photonic devices. This work presents core/shell colloidal quantum dots (CQDs) which have the quantized energy levels, excellent band gap tunability, and possess significant SA performance. When the band gap is close to the pump pulse energy, the CQDs show significant resonant SA response. At the same excitation conditions, the core/shell CQDs dispersions show better SA response than graphene dispersions, and comparable to the recently reported molybdenum disulfide. The carrier dynamics of the SA of the CQDs is analyzed systematically. The research has also found that the two‐photon absorption of the CQDs show nearly cubic power law of the band gap, while the SA performance keeps almost the same in the nonresonant regime. Further, superior passive Q‐switched laser behavior is observed using the CQDs as a saturable absorber. The results directly reveal the physical processes of this basic problem and broaden the applications of CQDs in photonic devices.

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Section: Resultsmentioning

confidence: 69%

Ultrafast Saturable Absorption of Core/Shell Colloidal Quantum Dots

Zhang

Dong

et al. 2016

Part. Part. Syst. Charact.

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“…The TPA coefficient β is set to be 0.3 cm MW in order to obtain the closest agreement with the experimental results. This value is somewhat smaller than the 2 cm MW −1 typically reported by studies that use picosecond and femtosecond pulses with peak intensities of several MW cm −2 [36,37]. The discrepancy between the two coefficients may indicate a saturation of the TPA process by Pauli blocking, as our experiment was performed using GW cm −2 peak intensities.…”

Section: Theory Of Perturbative Fwmmentioning

confidence: 54%

“…This observation indicates that the main contribution to the pump-probe response in InSb originates from a long-living electron-hole plasma produced by the intense THz field of the pump pulse. Possible mechanisms of free carrier generation by an excitation below the bandgap of InSb such as impact ionization [15], two-photon absorption (TPA) [36] or interband tunneling [37] have been studied previously. Here we concentrate on the FWM signal, which characterizes coherence induced in the sample by the phase-stable THz pulses.…”

Section: Field-sensitive Two-dimensional Spectroscopymentioning

confidence: 99%

Electric and magnetic terahertz nonlinearities resolved on the sub-cycle scale

et al. 2013

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Table-top sources of intense multi-terahertz (THz) pulses have opened the door to studies of extreme nonlinearities in the previously elusive mid-to far-infrared spectral regime. We discuss two concepts of fully coherent coupling of phase-locked THz pulses with condensed matter. The first approach demonstrates two-dimensional multi-THz spectroscopy of the semiconductor material InSb. By phase-and amplitude-sensitive detection of the nonlinear optical response, we are able to separate incoherent pump-probe signals from coherent four-wave mixing and reveal extremely non-perturbative nonlinearities. While this class of interactions is mediated by the electric field component of the THz pulse, the second approach is complementary, as it demonstrates that, alternatively, the magnetic THz field may be exploited to selectively control the spin degree of freedom in antiferromagnetic NiO.

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“…This means that 2PA coefficients in narrow-gap semiconductors are two to three orders of magnitude larger than in large-gap semiconductors. For example, ZnSe (E g = 2.67 eV) has a 2PA coefficient, Į 2 § 4.4 cm/GW at 532 nm [5], while for InSb (Eg = 0.23 eV), , Į 2 § 2 cm/MW in the range 8 to 12 ȝP [6]. Our experimental studies show that extremely nondegenerate (END) 2PA coefficients can exceed their degenerate counterparts by two to three orders of magnitude, thus allowing the large coefficients reserved for small bandgap materials to be realized in wide gap semiconductors.…”

Section: Introductionmentioning

confidence: 99%