TY  - JOUR
A1  - Elsner, Robert
A1  - Ullmann, Roland
A1  - Heuer, Axel
A1  - Menzel, Ralf
A1  - Ostermeyer, Martin
T1  - Two-dimensional modeling of transient gain gratings in saturable gain
 media
JF  - OPTICS EXPRESS
N2  - A transient two-dimensional model describing degenerate four-wave mixing inside saturable gain media is presented. The new model is compared to existing one-dimensional models with their qualitative results confirmed. Large quantitative differences with respect to peak reflectivity and optimum pump fluence are observed. Furthermore, the influence of the beam focus size, the transverse position and the crossing angle on the reflectivity of the grating is investigated using the improved model. It is demonstrated that the phase conjugate reflectivity depends sensitively on the transverse features of the interacting beams with a transverse shift in the position of the pump beams yielding a threefold improvement in reflectivity. (C) 2012 Optical Society of America
Y1  - 2012
U6  - https://doi.org/10.1364/OE.20.006887
SN  - 1094-4087
VL  - 20
IS  - 7
SP  - 6887
EP  - 6896
PB  - OPTICAL SOC AMER
CY  - WASHINGTON
ER  - 
TY  - JOUR
A1  - Menzel, Ralf
A1  - Puhlmann, Dirk
A1  - Heuer, Axel
A1  - Schleich, Wolfgang P.
T1  - Wave-particle dualism and complementarity unraveled by a different mode
JF  - Proceedings of the National Academy of Sciences of the United States of America
N2  - The precise knowledge of one of two complementary experimental outcomes prevents us from obtaining complete information about the other one. This formulation of Niels Bohr's principle of complementarity when applied to the paradigm of wave-particle dualism-that is, to Young's double-slit experiment-implies that the information about the slit through which a quantum particle has passed erases interference. In the present paper we report a double-slit experiment using two photons created by spontaneous parametric down-conversion where we observe interference in the signal photon despite the fact that we have located it in one of the slits due to its entanglement with the idler photon. This surprising aspect of complementarity comes to light by our special choice of the TEM01 pump mode. According to quantum field theory the signal photon is then in a coherent superposition of two distinct wave vectors giving rise to interference fringes analogous to two mechanical slits.
Y1  - 2012
U6  - https://doi.org/10.1073/pnas.1201271109
SN  - 0027-8424
VL  - 109
IS  - 24
SP  - 9314
EP  - 9319
PB  - National Acad. of Sciences
CY  - Washington
ER  - 
TY  - JOUR
A1  - Heuer, Axel
A1  - Sagahti, A.
A1  - Jechow, Andreas
A1  - Skoczowsky, D.
A1  - Menzel, Ralf
T1  - Multi-wavelength, high spatial brightness operation of a phase-locked stripe-array diode laser
JF  - Laser physics
N2  - Stable continuous wave multi-wavelength operation of a stripe-array diode laser with an externalcavity spectral beam combining geometry is presented. In this setup each emitter of the stripe-array is forced to operate at a different wavelength, which leads to a decoupling between the usually phase-locked emitters. With a reflective diffraction grating with a period of 300 lines per mm, 33 equidistant laser lines around a center wavelength of 978 nm were realized, spanning a spectral range of 26 nm. With this novel approach near-diffraction limited emission with a beam quality of M (2) < 1.2 and an output power of 450 mW was achieved. This laser light source can be used for applications requiring low temporal but high spatial coherence.
Y1  - 2012
U6  - https://doi.org/10.1134/S1054660X12010057
SN  - 1054-660X
VL  - 22
IS  - 1
SP  - 160
EP  - 164
PB  - Pleiades Publ.
CY  - New York
ER  -