High performance plasmonic random laser based on nanogaps in bimetallic porous nanowires

Abstract

A plasmonic random laser is fabricated using gold-silver bimetallic porous nanowires with abundant nanogaps that provide strong feedback or gain channels for coherent lasing from dye molecules. The strong confinement of the nanogaps allows the bimetallic porous nanowire-based random laser, which is pumped by ns pulses, to operate with a very low threshold and extremely low concentrations of Rhodamine 6 G (as low as 0.067 mM). This random laser can be used as a pump source for another coherent random laser based on oxazine. These results provide a basis for studies of coherent random lasing pumped by another random laser.

Broadband plasmonic silver nanoflowers for high-performance random lasing covering visible region

“…All the extinction spectra exhibit broadband characteristic over the whole visible spectral range without any obvious resonance peak [20,22], which is in accord with the simulated results ( Figure S4, Supporting Information). Using the broadband enhancement effect induced by the abundant randomly distributed nanogaps with different random sizes in Ag NFs as the scatterers to supply strong gain for optical feedback [20,22], the dyes C440, C153, R6G, and Oz are chosen as the gain media to build colorful random lasing systems, labeled as RL-C440, RL-C153, RL-R6G, and RL-Oz, separately. The photoluminescence spectra of these dyes are centered at approximately 435, 540, 575, and 640 nm, whereas the absorption spectra are centered at approximately 380, 430, 520, and 610 nm, respectively, as shown in Figure 4B.…”

“…Compared to the traditional surface plasmonic resonance random lasers [39] and the reported "hot-spot" effect-based random lasers [20,47], Ag NFbased random lasers have the minimal working threshold of 0.24 MW cm −2 and the smallest linewidth of 0.048 nm when pumped by the nanosecond pulses. Good performance is induced by the interparticle coupling effect and the unique morphology of Ag NFs with the relative small size and abundant nanogaps, which can efficiently enhance the local electromagnetic field.…”

“…There are more spikes that emerged in the spectra as the pump power densities further increase, as shown in Figure 5A (blue and olive curves). The appearance of sharp spikes indicates building the coherent feedback in random system, resulting from the strong feedback and large enhancement of the local electromagnetic field induced by the nanogaps within Ag NFs [20][21][22]. The probability of coherent random lasing [37,38], defined as the ratio of the number of spectra with coherent modes to the total number of spectra captured, is used to determine the threshold of coherent random lasing as shown in Figure 5B.…”

“…For example, Popov et al [14] found that gold nanoparticles enhanced the gain in random laser system containing dyes and gold nanoparticles. To achieve random lasing with lower threshold and multicolor emissions, nanogap-based random lasing was proposed by choosing the gold-silver (Au-Ag) bimetallic porous nanowires with abundant nanogaps that provide strong feedback or gain channels for coherent lasing from dye molecules [20,21]. Based on the strong confinement characteristic of the nanogaps, Au-Ag bimetallic nanowire-based random lasers operate at a low threshold and have high Q-factors in a wide visible spectral range [22].…”

Direct writing of flexible bimetallic nanoparticles for hybrid plasmon response

“…7 A wide range of applications have also been developed to take advantage of these properties, including imaging, 2 surface enhanced Raman scattering, 8,9 biomolecular recognition, 10 sensors, 11,12 waveguides, 13 solar cells, 14 and random lasers. 15,16 Recently, hybrid metallic materials, and particularly bimetallic materials, have attracted widespread attention for the design of desirable surface plasmon resonance curves and the development of a new generation of more powerful applications. [17][18][19][20][21] Gold nanoparticles generally have good chemical resistance properties and broad surface plasmon resonance peaks, 22 and silver nanoparticles show narrow surface plasmon resonance peaks.…”