Low threshold photonic crystal laser based on a Rhodamine dye doped high gain polymer

Abstract

We demonstrate low threshold lasing oscillation in a photonic crystal (PhC) laser by using tert-butyl Rhodamine B (t-Bu-RhB) doped gain media. Lactonic t-Bu-RhB is synthesized to improve doping concentration in polymethylmethacrylate (PMMA) films, and then isomerized to the zwitterion form to achieve highly fluorescent gain medium. The t-Bu-RhB doped PMMA film is sandwiched by a pair of polystyrene colloidal crystals to construct a PhC resonating cavity. Single-mode laser oscillation at 592 nm is observed when the PhC resonating cavity is pumped by a Nd:YAG laser. The lasing threshold is 0.12 MW cm(-2) utilizing 6.9 wt% t-Bu-RhB doped PMMA films, which is only 1/60 of that with 3 wt% t-Bu-RhB doped PMMA films. The concentration-dependent lasing action is attributed to different gain factors of the t-Bu-RhB doped PMMA films. Furthermore, a spatially and spectrally coherent laser beam from the PhC resonating cavity is verified by exploring the far-field image and angular dependence of the lasing emission. The approach provides a facile and efficient strategy to reduce the lasing threshold for fabricating low threshold PhC lasers.

Electrically Controlled Lasing in Supercooled Liquid Crystal Blue Phase I Microdroplets

“…It should be noted that the surface anchoring and the physical confinement of BPs can enhance their thermal and mechanical stability. Stable BPs exhibit a reversible surface-switch mode driven by a low electric field that has been reported. − …”

Inhibited/enhanced fluorescence of embedded fluorescent defects by manipulation of spontaneous emission based on photonic stopband

“…This design would result in the improved solubility of the dye in photoresist, and suppression of the aggregation of the dye molecules aer doping in polymer. 3,27,28 Reectance spectra of the CCs were derived in normal incidence to the substrate to evaluate the photonic stopband. As shown in Fig.…”

“…† The emission enhancement occurs on the blue side of the photonic stopband, which could be attributed to the band edge effect of the CCs. 3,[30][31][32][33][34][35] The modication of the CCs on the spontaneous emission of the allyl-FL inltrated in the CCs suggests that uorescent intensity of the embedded uorescent defects would be affected by the CCs.…”

“…Colloidal crystals (CCs) are three dimensional photonic crystals, in which the propagation of photons within a certain frequency band is forbidden due to Bragg diffraction, resulting in the formation of a photonic stopband. 1,2 Numerous potential applications have been explored by utilizing photonic stopbands of the CCs, including low-threshold lasers, [3][4][5] sensors, 6,7 batteries, 8 solar cells, 9 ultrasensitive detection, 10 anti-counterfeiting, 11 and displays. 12 Well-designed and controllably positioned defects in CCs are oen required to achieve these purposes.…”

Symmetric Continuously Tunable Photonic Band Gaps in Blue-Phase Liquid Crystals Switched by an Alternating Current Field

“…Photonic crystals (PCs) of the periodic modulated dielectric constant are attractive optical nanostructure materials, which can be applied in controlling and manipulating the light flow. − Therefore, PCs have enormous potential applications in PC fibers, PC sensors, , thin film optics, nanolasers, − and full-color reflective displays. , The functional PC materials of urgent demand can be achieved by changing the external stimuli, for example, mechanical force, , thermal energy, , electric field, − light, − and magnetic field. , Among the various external stimuli, the electric field is the easiest method to turn the photonic band gap or lattice structure of PCs . Much effort has been taken to fabricate the stimuli-responsive PCs in the past two decades, such as layer-by-layer stacking techniques using microfabrication tools, electrochemical etching, laser beam-scanning chemical vapor deposition, holographic lithography, and self-assembly of monodisperse colloidal particles.…”