Whispering gallery mode emission from a composite system of CdTe nanocrystals and a spherical microcavity

Abstract

We have studied the optical properties of a novel quantum dot-microcavity system consisting of CdTe nanocrystals attached to a melamine formaldehyde latex microsphere. The spheres were studied using conventional and confocal microscopy, the confocal system revealed defects in some spheres. The coupling between the emission of the nanocrystals and the spherical cavity modes was realized. Periodic very narrow peaks of the emission spectra corresponding to the whispering gallery modes were detected with strong emission into selected modes at a high pump intensity.

Whispering gallery modes in photoluminescence and Raman spectra of a spherical microcavity with CdTe quantum dots: anti-Stokes emission and interference effects

“…We suggest that the observed reduction of the peaks intensity in the spectra of a CdTe/PS microsphere is due to absorption by QDs that are coupled to the relevant WGM. It is well-known that absorption or gain or refractive index variation alter the Q value of the spherical microcavity [16]. Because of the Stokes shift (30 nm) between the intrinsic PL peak and the absorption peak of the CdTe QDs, the absorption coefficient is reduced on the long-wavelength part of the PL band (Fig.…”

Three dimensional confocal microscopy of fluorescent microspheres: imaging and size determination

“…Coupling NCs (quantum dots) to a high-Q WGM of a microsphere can provide a strong coherent interaction between the WGM and the electronic states of the dots. Due to the effect of quantum confinement in quantum dots, this new concept allows one to tune both the modes of microcavities and NCs into resonance providing the most efficient mode coupling 8 . In this paper, we experimentally studied both the bright-field and fluorescence images of microspheres by conventional and confocal scanning polarization microscopes.…”

Photonic molecules modes in resonantly coupled spherical microcavities with semiconductor nanocrystals

“…This phenomenon has been demonstrated in a system of two square, photonic dots coupled by a narrow channel 7 in a dye-stained bisphere system 9,11,12 , in photonic dots doped by CdSe nanocrystals (NCs) 13 and in chains of polymer-blend microparticles 14 . However recent theoretical considerations 10 and experimental studies 15,16 reveal complex internal distribution of density of photonic states of PM originating from lifting of degeneracy of PM modes with respect to the azimuthal index.…”