Dynamic Lasing from All‐Organic Two‐Dimensional Photonic Crystals

Abstract

room temperature [43]. After incubation, cells were doubly washed with PBS and imaged using the Nikon Eclipse TE300 inverted fluorescent microscope. Images were captured every 10 mm apart (as measured by a stage micrometer, Nikon) in both X and Y dimensions. The cell distribution was approximately uniform within each image, suggesting that the gradient does not influence the cell behavior over the distance corresponding to the image field (up to 1 mm). This point is further supported by the fact that PHEMA thickness varies only by ≈ 0.2 nm (below the detection limit of our ellipsometer) over a distance of 1 mm.

Tuning the wavelength of lasing emission in organic semiconducting laser by the orientation of liquid crystalline conjugated polymer

“…7-10͒, microcavities, 11-13 photonic crystals, 14 and so on. Among them, the DFB structure has received much attention as it offers long gain lengths resulting in very low thresholds.…”

Electrically Tunable Organic Distributed Feedback Lasers Embedding Nonlinear Optical Molecules

“…This result corresponds to a tunability coeffi cient of 0.17 nm/V, almost twice the best performances reported by other electrically-driven tunability concepts. [18][19][20][21][22] Lasing occurs in the low-energy tail of the gain peak, evidencing that the shift of the waveguide cutoff wavelength is responsible of the observed tunability. Upon tuning, we fi nd a slight increase of the lasing mode linewidth (inset of Figure 4 d), since the used grating is less effective in providing feedback when the emission peak blue-shifts.…”

“…[ 17 ] The basic idea of all these approaches is the variation of the DFB period ( Λ ) or of other geometric characteristics and, consequently, of the effective refractive index (n eff ), since the emission wavelength ( λ ) is given by the Bragg condition, m λ = 2 n eff Λ , where m is the diffraction order. Electrical tunability is reported in liquid crystal lasers, [18][19][20] by using a liquid crystal as cladding layer, [ 21 ] or an electroactive substrate. [ 22 ] Most of these methods allow continuous and reversible tuning of the emission wavelength within a range < 10 nm, whereas a remarkable tunability over 47 nm has been achieved in Ref.…”

Temperature effect on the lasing from a dye-doped two-dimensional hexagonal photonic crystal made of holographic polymer-dispersed liquid crystals

“…7͒ and 2D dye-doped photonic crystal ͑PC͒. 8,9 In dye-doped H-PDLC PCs, the groupvelocity anomaly, 10 where the group velocity is small over a wide range of wave vectors, is responsible for the possible local field enhancement. The tunable properties of lasing based on dye-doped H-PDLC have been discussed in the presence of electric field, such as in reflection grating, 11,12 transmission grating, 5,13 and 2D square PC.…”

“…The tunable properties of lasing based on dye-doped H-PDLC have been discussed in the presence of electric field, such as in reflection grating, 11,12 transmission grating, 5,13 and 2D square PC. 8 The temperature dependent tunable properties of lasing have also been studied in PDLC ͑Ref. 14͒ and H-PDLC transmission grating, 15 however, rarely in 2D H-PDLC PCs.…”