Highly sensitive fibre surface-enhanced Raman scattering probes fabricated using laser-induced self-assembly in a meniscus

Abstract

Fibre surface-enhanced Raman scattering (SERS) probes have the advantages of flexibility, compactness, remote sensing capability and good repeatability in SERS detection and thus have a range of different applications. However, it is difficult to realize simple, low-cost and high-throughput preparations of fibre SERS probes with high sensitivity and desirable repeatability using the currently available fabrication techniques, which restricts their practical applications. We report here a simple, low-cost method using laser-induced self-assembly to realize the fast fabrication of fibre SERS probes with high sensitivity and excellent reproducibility. By lifting the fibre facet above a pre-synthesized nanoparticle colloid, a meniscus can be formed with the help of the surface tension of the liquid. Using irradiation from an induced laser guided by the fibre, localized thermal effects on the nanoparticles in the meniscus control the growth of the fibre probes and the electromagnetic interactions among the closely spaced nanoparticles assist the arrangement of nanoparticle clusters on the fibre facet. The prepared fibre probes showed a very high SERS sensitivity of 10(-10) M for p-aminothiophenol using a portable commericial Raman spectrometer with a short integration time of 2 s. They also showed excellent repeatability with relative standard deviations <2.8% in the SERS peak intensities for different detections with the same probe and 7.8% for different fibre probes fabricated under the same conditions.

Fibre Optic SERS Probes For Remote Sensing

“…Focused ion beam milling and electron beam lithography have also been used to create fine and precise periodic structures on fiber tips which can provide high tunability [102]- [104]. Laser induced self-assembly of nanoparticles at the surface of fiber has also been explored to create SERS optical fibers [105]. Pre-fabricated nanoparticles can be used in such an approach where the particles are trapped in a meniscus on the fiber tip and a laser is applied through the fiber to perform self-assembly at the tip of an optical fiber.…”

Microcavity Fiber SERS Probe Coated With Ag Nanoparticles For Detecting Antibiotic in Milk

“…The guided mode propagation characteristics of Raman light in the optical fiber can effectively increase the area of light-matter interaction, and the number of excited molecules will increase significantly to increase the intensity of the Raman signal. In addition, the SERS signal collected by fiber probe is the integration of the entire SERS active area, which greatly reduces the uniform distribution requirements of SERS "hot spots" and improves the signal repeatability [19,20] . It also can prevent contamination of the optical lens of the Raman system when detecting toxic and volatile substances.…”

Miniature optical fiber sensors using surface enhanced Raman spectroscopy (SERS) for remote biochemical sensing

“…Various studies have focused on creating optical fibers for remote SERS sensing. These include etched imaging fiber bundles coated with silver films [19], oblique angle deposition of silver films onto fiber tips [20], laser induced self-assembly of Ag nanocubes in a meniscus [21] and, D-shaped fiber tips ablated with femtosecond lasers to create SERS sensors [22]. Trapping nanospheres on fiber surfaces was achieved by Stokes et al [23] and NSL for SERS on fiber tips was used more recently by Pisco et al [24].…”