Reciprocal transmittances and reflectances: An elementary proof

We present an elementary proof concerning reciprocal transmittances and reflectances. The proof is direct, simple, and valid for the diverse objects that can be absorptive and induce diffraction and scattering, as long as the objects respond linearly and locally to electromagnetic waves. The proof enables students who understand the basics of classical electromagnetics to grasp the physical basis of reciprocal optical responses. In addition, we show an example to demonstrate reciprocal response numerically and experimentally.Comment: 6 pages, 5 figures. RevTEX4. Improved wording. Physics Educatio

Plasmonic crystals for ultrafast nanophotonics: Optical switching of surface plasmon polaritons

We demonstrate that the dispersion of surface plasmon polaritons in a periodically perforated gold film can be efficiently manipulated by femtosecond laser pulses with the wavelengths far from the intrinsic resonances of gold. Using a time- and frequency- resolved pump-probe technique we observe shifting of the plasmon polariton resonances with response times from 200 to 800 fs depending on the probe photon energy, through which we obtain comprehensive insight into the electron dynamics in gold. We show that Wood anomalies in the optical spectra provide pronounced resonances in differential transmission and reflection with magnitudes up to 3% for moderate pump fluences of 0.5 mJ/cm^2.Comment: 5 pages, 4 figure

Asymptotic bounds on the absorptive parts of the elastic scattering amplitudes

We establish exact bounds on the absorptive parts A(s,t) of an elastic scattering amplitude (spinless case) and evaluate them for positive t values lying within the Lehmann-Martin ellipse [the major axis = 2(1+t0/2k2)]. These bounds are used to derive a number of asymptotic results; e.g., (i) the "diffraction-peak width" W is larger than Wmin~4t0/(1+λ)2× (1-1/2σ)(lns)2 (for s→∞); (ii) the leading Regge trajectory for t0 > t > 0 lies below [1+(t/t0)1/2]-λ[1-(t/t0)1/2]; (iii) there are no complex zeros of A(s,t) for |t| < 4t0/(1+λ)2e2(lns)2 (for s→∞) and no real zeros for t0 > t >-Wmin, where λ=lims→∞lnσtot(s)/lns and σ=lims→∞t0σtot(s)/4Π(lns)2

Carrier dynamics in GaAs/AlAs quantum wire arrays

635-641Measurements of ps time resolved luminescence spectra, performed on a GaAS/AlAs quantum wire array are reported. The array is excited by picosecond laser pulses at different densities, from 0.05×nM to 2×nM are, where ×nM is the Mott density in 1-D (= 8×105 cm-1).</span