Spontaneous emission of light from a crystal

Thomas Møller Søndergaard

Roy J. Glauber

Priya Priya, Rajesh V. Nair

The propagation and emission of light in a real photonic crystal is routinely affected by the intrinsic disorder and its finite-size. Thus, theoretical calculation based on the notion of a defect free crystal with an infinite thickness is irrational in the real world experiments. Here, we report an acute modification of light propagation and emission induced by the finite-size of the crystal. We have measured the emission intensity and rate from single domain of the crystal to study the finite size effect on the spontaneous emission suppression. The results show spatial fluctuation of spontaneous emission suppression across domains that have a linear scaling with crystal size. The results have implications in contriving devices pertaining to controlled spontaneous emission such as in cavity quantum electrodynamics.

A F J Levi

Ivan S. Nikolaev, Peter Lodahl, Willem L. Vos

We have performed angle-resolved measurements of spontaneous-emission spectra from laser dyes and quantum dots in opal and inverse opal photonic crystals. Pronounced directional dependencies of the emission spectra are observed: angular ranges of strongly reduced emission adjoin with angular ranges of enhanced emission. It appears that emission from embedded light sources is affected both by the periodicity and by the structural imperfections of the crystals: the photons are Bragg diffracted by lattice planes and scattered by unavoidable structural disorder. Using a model comprising diffuse light transport and photonic band structure, we quantitatively explain the directional emission spectra. This work provides detailed understanding of the transport of spontaneously emitted light in real photonic crystals, which is essential in the interpretation of quantum optics in photonic-band-gap crystals and for applications wherein directional emission and total emission power are controlled.

A F J Levi