Speaker
Prof.
Heinz-Wilhelm Hübers
(German Aerospace Center (DLR) and Humboldt University Berlin)
Description
Hydrogen-like impurity centers in monocrystalline Silicon can be utilized for terahertz(THz) lasers. Several types of such lasers have been demonstrated. The
lasers operate at low lattice temperatures under optical pumping
with a free electron laser (FEL). They emit light frequencies between 1.2 and 6.9 THz.
Dipole-allowed optical transitions between particular excited
states of substitutional impurities are utilized. Population inversion induced by optical pumping with the FEL is achieved due to specific electron–phonon interactions inside the
impurity atom. This results in long-living and short-living
excited states of the impurity centers. Another type of THz laser
utilizes stimulated resonant Raman-type scattering of photons
by a Raman-active intracenter electronic transition. By varying
the pump-laser frequency, the frequency of the Raman intracenter
silicon laser can be continuously changed between at
least 4.5 and 6.4 THz. In addition, fundamental
aspects of the laser process provide new information about the
peculiarities of electronic capture by shallow impurity centers
in silicon, lifetimes of nonequilibrium carriers in excited
impurity states, and electron–phonon interaction.
Primary author
Prof.
Heinz-Wilhelm Hübers
(German Aerospace Center (DLR) and Humboldt University Berlin)
Co-authors
Dr
Alex van der Meer
(Radboud University)
Mr
Andreas Pohl
(Humboldt University Berlin)
Dr
Britta Redlich
(Radboud University Nijmwegen)
Dr
Nikolay Abrosimov
(Leibniz Institute for Crystal Growth)
Mr
Nils Dessmann
(Humboldt-University Berlin)
Dr
Roman Zukavin
(IPM-RAS)
Dr
Sergey Pavlov
(German Aerospace Center)
Prof.
Valery Shastin
(IPM RAS)
