Zobrazeno 1 - 10
of 59
pro vyhledávání: '"Keita Ohtani"'
Autor:
Keita Ohtani, Dana Turčinková, Christopher Bonzon, Ileana-Cristina Benea-Chelmus, Mattias Beck, Jérôme Faist, Matthias Justen, Urs U Graf, Marc Mertens, Jürgen Stutzki
Publikováno v:
New Journal of Physics, Vol 18, Iss 12, p 123004 (2016)
GaAs/AlGaAs quantum cascade lasers based on four quantum well structures operating at 4.7 THz are reported. A large current density dynamic range is observed, leading to a maximum operation temperature of 150 K for the double metal waveguide device a
Externí odkaz:
https://doaj.org/article/ee6fb376c5e944b092e2e7418a38f8dd
Publikováno v:
New Journal of Physics, Vol 17, Iss 2, p 023050 (2015)
Terahertz quantum cascade lasers based on InGaAs wells and quaternary AlInGaAs barriers were measured in magnetic field. This study was carried out on a four-quantum-well active-region design with photon energy of 14.3 meV processed with both Au and
Externí odkaz:
https://doaj.org/article/32a04178a4b04c128720cbbdb9a2d67a
Autor:
Aaron Maxwell Andrews, Hermann Detz, Jérôme Faist, Gottfried Strasser, Martin J. Süess, Mattias Beck, Tobias Zederbauer, Werner Schrenk, Keita Ohtani
Publikováno v:
ACS Photonics. 3:2280-2284
We report on the operation of a double metal waveguide far-infrared quantum cascade laser emitting at 28 μm, corresponding to the AlAs-like phonon reststrahlen band. To avoid absorption by AlAs-like optical phonons, the Al-free group V alloy GaAs0.5
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::79f752d28e6821777f59521c30ea2cf9
https://doi.org/10.1021/acsphotonics.6b00750
https://doi.org/10.1021/acsphotonics.6b00750
Publikováno v:
ACS Photonics. 3:2297-2302
Strain-compensated InGaAs/AlInGaAs terahertz quantum cascade lasers grown by molecular beam epitaxy are reported. A choice of a moderate amount of strain in the wells (−0.24%) and in the quaternary barriers (+1.07%) makes it possible to coherently
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::55f3bbef67816036c3d8f1cb551555c1
https://doi.org/10.1021/acsphotonics.6b00376
https://doi.org/10.1021/acsphotonics.6b00376
Autor:
Camille Ndebeka-Bandou, Keita Ohtani, Bo Meng, Lorenzo Bosco, Jérôme Faist, Martin Franckié, Mattias Beck
Publikováno v:
Science Advances, 5 (7)
Science Advances
Science Advances
We report the direct observations of coherently emitted phonon polaritons via their photon, phonon, and polariton signatures.
We report a device that provides coherent emission of phonon polaritons, a mixed state between photons and optical phon
We report a device that provides coherent emission of phonon polaritons, a mixed state between photons and optical phon
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a2aff652abdec0557b7bba46564c24e5
http://arxiv.org/abs/1808.09844
http://arxiv.org/abs/1808.09844
Autor:
Jérôme Faist, Martin Franckié, Keita Ohtani, Lorenzo Bosco, Mattias Beck, Camille Ndebeka-Bandou
Publikováno v:
Scopus-Elsevier
We demonstrate an electrically pumped laser that generates phonon polaritons. The emission also appears directly on a Raman spectrum measurement exhibiting a Stokes and anti-Stokes component with the expected shift of 48 meV.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::966049a6797f8588c325af85c14cda93
https://doi.org/10.1364/cleo_si.2018.sf3g.5
https://doi.org/10.1364/cleo_si.2018.sf3g.5
We develop a quantum model for the calculation of the gain of phonon-polariton intersubband lasers. The polaritonic gain arizes from the interaction between the electrons confined in a quantum well structure and the phonon confined in one layer of th
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d412b211a37b8f26b3c7b2690dcc684c
Autor:
Hideo Ohno, Keita Ohtani
Publikováno v:
The Review of Laser Engineering. 36:70-74
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::fee9020b3f5b58565d17b8a036b1bb1f
https://doi.org/10.2184/lsj.36.70
https://doi.org/10.2184/lsj.36.70
Publikováno v:
physica status solidi (b). 243:773-777
The surface morphologies of ZnO thin films grown on Al 2 O 3 (1120) (a-plane sapphire) substrate by plasma-assisted molecular beam epitaxy (PAMBE) were systematically investigated by in situ reflection high energy electron diffraction (RHEED) and ex
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::fd175c6ae5a982377babe1822acf7387
https://doi.org/10.1002/pssb.200564657
https://doi.org/10.1002/pssb.200564657
Autor:
Keita Ohtani, Hideo Ohno, Y. Yamada, Junya Nishii, Akira Ohtomo, Masahiro Ikeda, Masashi Kawasaki
Publikováno v:
Applied Surface Science. 252:2507-2511
Using composition-spread technique, we have grown metastable Mg 1− x Ca x O solid solution films on ZnO layers by pulsed laser deposition. All the films exhibited (1 1 1) oriented cubic phase. Despite a large miscibility gap, no phase separation to
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::cec2e99ffabc425215c24ed1d4eccf5e
https://doi.org/10.1016/j.apsusc.2005.06.040
https://doi.org/10.1016/j.apsusc.2005.06.040