Emission studies on photonic crystals fabricated using dyed polystyrene colloids

Abstract

Three dimensionally ordered photonic crystals are fabricated with rhodamine B dyed polystyrene colloidal spheres using the inward growing self-assembling method in less than 3 h. This avoids the difficulties due to infiltration of active materials into passive photonic crystals. The superior optical quality of the photonic crystals fabricated using this method results in high reflectance values even at large angles of incidence. The study of emission characteristics on these functionalized photonic crystals shows a clear trend dependent on the angle of emission, wavelength, and the angle-resolved transmittance. The dip observed in the emission spectrum clearly matches the photonic stop band position at different angles of observation. The emission spectrum measured at different angles was found to follow a simple functional form related to the intrinsic emission of the dye and the stop band effect due to the photonic crystal environment.

Spectral narrowing and lasing threshold in self-assembled active photonic crystal

“…Yamasaki et al discussed the emission in dye doped polystyrene (PS) PhC [8]. A similar study was reported by our group for Rhodamine-B dye doped polystyrene (PS-RhB) PhC in 2007 [9]. Li et al reported the stop band effect and spectral narrowing in RhB-doped poly(styrenemethyl methacrylate-acrylic acid) (P(St-MMA-AA)) PhC [10].…”

“…The stop band of the crystal has affected different ranges of emission spectrum at different angles. The emission and reflection spectra of this crystal do not overlap at angles larger than 45° [9]. Hence the emission recorded at a larger angle of 60°is considered to be the intrinsic emission of the dye (Fig.…”

“…It is observed that the PhC has maximum number of allowed modes at the edges of its stop band. In earlier reports, it is discussed that the spontaneous emission of an embedded emitter in a PhC gets modified because of non-uniform distribution of photon density of states in the PhC system [3][4][5][6][7][8][9][10]. If the PhC has the pseudo band gap property, then an angle-dependent modification in the spontaneous emission will be observed.…”

Thickness measurement of colloidal opal crystal growth by Bragg reflection

“…The disallowed band of wavelengths in photonic crystals is called the photonic band gap, which is similar to the energy gap of the electrons in the semiconductors. The photonic band gap gives rise to distinct optical phenomena, such as the inhibition of spontaneous emission [1,2], high-reflecting omnidirectional mirrors [3,4], and low-loss-waveguide [5].…”

Photonic-band-edge-induced lasing in self-assembled dye-activated photonic crystals

“…Accordingly, the emission intensity and the rate decrease inside the photonic stop gap with the reduction of the LDOS. Inhibition of spontaneous emission of dyes and quantum dots has been observed in self-assembled colloidal photonic crystals [9,[14][15][16][17]. The enhancement of LDOS in the frequency range of the stop gap can be achieved by creating intentional defects that effectively act as cavities with high quality factors in the otherwise periodic structure [2].…”