We present experimental studies on the transverse mode emission behaviour of oxide-confined Vertical Cavity Surface Emitting Lasers (VCSELs). VCSELs with aperture diameters of 6um and 11um exhibit a wide variety of emission patterns from low order Hermite- Gaussian modes to high order Laguerre-Gaussian modes. We obtain detailed information about the spatial gain distribution by recording sponta...

s. We have studied phonon hole burning phenomenon. According to the plastic deformation model proposed by us, some characteristics of holes depend on the amplitude of resonant oscillation exited and the crystal condition of specimen. We studied the effect of heat treatment for the particles on holes. In NH4HZP04 specimen, the increase of decay time for oscillation and larger holes were found. N...

We investigate the engraving of spectral holograms in porphyrin-derivative-doped solids, where a tautomerization process gives rise to persistent spectral hole burning at low temperature. Starting with a microscopic model of this process, we build a theory that connects conventional narrow-band hole burning with the engraving and retrieval of broadband holograms, in samples with possibly large ...

Ž . We have observed laser-jitter-enhanced high-resolution spectra of three hyperfine states in the ground level H of 4 Pr :Y SiO using coherent population trapping and phase-correlated four-wave mixing. We have also observed optical 2 5 Raman pulse excited two-photon spectral hole-burning. The observed high-resolution spectra are due to a laser-jitter-suppressed Raman coherence window in an in...

A previously developed numerical model based on Maxwell–Bloch equations was modified to simulate optical coherent transient and spectral hole burning processes with noisy laser sources. Random walk phase noise was simulated using laser-phase sequences generated numerically according to the normal distribution of the phase shift. The noise model was tested by comparing the simulated spectral hol...

Persistent spectral nonphotochemical hole-burning (NPHB) spectroscopy has recently been applied to dye molecules in cells. The sensitivity of NPHB to the nanoenvironment of the probe is well established. It has been shown that NPHB applied to bulk suspensions of cultured human cells can distinguish between normal and cancer cells. Thus, NPHB has potential as a diagnostic cancer tool. For this r...

We show for the ®rst time persistent spectral hole burning by simultaneous absorption of two 1138 nm photons in an inhomogeneously broadened S1 S0 …Qy† transition of unstable photo-tautomer of chlorin in polymer ®lm at low temperature. Spectrally selective hole burning is achieved due to high (10%) quantum eciency of photo-transformation in that system and high peak intensity (tens of GW/cm) o...

R. N. Shakhmuratov, A. Rebane, P. Mégret, and J. Odeurs Instituut voor Kernen Stralingsfysica, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, B-3001 Leuven, Belgium Optique Nonlinéaire Théorique, Université Libre de Bruxelles, Campus Plaine CP 231, B-1050 Bruxelles, Belgium Kazan Physical Technical Institute, Russian Academy of Sciences, 10/7 Sibirsky trakt, Kazan 420029 Russia Physics ...

We study spectral hole burning in the unstable tautomer form of free-base Br-tetraethylporphyrin in poly(vinyl butyral) "lm, which is created by photo-transformation of the stable tautomer form at low temperature.We report a Debye}Waller factor a"0.7 at 4 K, burning quantum e$ciency u&10~3 and thermal stability up to 115 K for this system. We observe for the "rst time that narrow-band illuminat...