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G Nimtz

Publications and source records attributed to G Nimtz.

18 recordsLinked to original sources
PubMed2002

Pulse reflection by photonic barriers.

The time behavior of microwaves undergoing partial reflection by photonic barriers was measured in the time and in the frequency domain. It was observed that for opaque barriers the reflection delay is almost independent of the barrier's length. This result corresponds to the Hartman effect in transmission.

Journal Article↗
PubMed2001

Negative phase time for scattering at quantum wells: a microwave analogy experiment.

If a quantum mechanical particle is scattered by a potential well, the wave function of the particle can propagate with negative phase time. Because of the analogy of the Schrödinger and Helmholtz equations this phenomenon is expected to be observable for electromagnetic wave propagation. Experimental data for electromagnetic wells realized by waveguides filled with different dielectrics now confirm this conjecture.

Journal Article↗
PubMed2001

Frustrated total reflection: the double-prism revisited.

Geometrical optics prohibits any penetration of light into an optically rarer medium in the case of total reflection. When sandwiching, however, the rarer medium between optically denser media, a transmitted beam can be observed in the third medium. The experiment is often realized by a double-prism arrangement [1]; the effect is called frustrated total reflection due to the enforced transmission. Amazingly, the reflected and transmitted beams are shifted with respect to geometrical optics as conjectured by Newton [2] and experimentally confirmed by Goos-Hänchen 250 years later [3]. However, inconsistent results on the spatial shifts have been reported [4-7]. Here we report on measurements of the Goos-Hänchen shift in frustrated total reflection with microwaves. We found an unexpected influence of the beamwidth and angle of incidence on the shift. Our results are not in agreement with both previous experiments [6,7] and theoretical predictions [8-10]. The topic of frustrated total reflection is important for both fundamental research and applications [11-13].

Journal Article↗