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Long wavelength interband cascade lasers

Applied Physics Letters

Massengale, J.A.; Shen, Yixuan; Yang, Rui Q.; Hawkins, Samuel D.; Klem, John F.

InAs-based interband cascade lasers (ICLs) can be more easily adapted toward long wavelength operation than their GaSb counterparts. Devices made from two recent ICL wafers with an advanced waveguide structure are reported, which demonstrate improved device performance in terms of reduced threshold current densities for ICLs near 11 μm or extended operating wavelength beyond 13 μm. The ICLs near 11 μm yielded a significantly reduced continuous wave (cw) lasing threshold of 23 A/cm2 at 80 K with substantially increased cw output power, compared with previously reported ICLs at similar wavelengths. ICLs made from the second wafer incorporated an innovative quantum well active region, comprised of InAsP layers, and lased in the pulsed-mode up to 120 K at 13.2 μm, which is the longest wavelength achieved for III-V interband lasers.

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TYPE Journal Article YEAR 2022
DOIOSTIScopus

The influence of surface impurities on photoelectric currents driven by intense soft x rays

Physics of Plasmas

Roberds, Nicholas A.

In an x-ray driven cavity experiment, an intense flux of soft x rays on the emitting surface produces significant emission of photoelectrons having several kiloelectronvolts of kinetic energy. At the same time, rapid heating of the emitting surface occurs, resulting in the release of adsorbed surface impurities and subsequent formation of an impurity plasma. This numerical study explores a simple model for the photoelectric currents and the impurity plasma. In this work, attention is given to the effect of varying the composition of the impurity plasma. The presence of protons or hydrogen molecular ions leads to a substantially enhanced cavity current, while heavier plasma ions are seen to have a limited effect on the cavity current due to their lower mobility. Additionally, it is demonstrated that an additional peak in the current waveform can appear due to the impurity plasma. A correlation between the impurity plasma composition and the timing of this peak is elucidated.

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TYPE Journal Article YEAR 2022
DOIOSTI
Results 8001–8025 of 99,299
Results 8001–8025 of 99,299