tweezing and manipulating nanomaterials on tapered optical fiber to develop surfaceenhanced raman spectroscopy (sers) substrate
abstract
a compact and cost-effective fiber-based probe was manufactured for the detection of chemicals
at low concentrations using surface-enhanced raman spectroscopy (sers). multi-mode optical
fiber was tapered with a dynamic etching process using hydrofluoric (hf) acid. the desired
length, tip diameter, and cone angle of the tapered fiber were obtained by using this process. the
sers substrate was prepared by depositing gold nanorods (gnrs) on the tapered fiber surface
by the phenomenon called optical tweezing (ot). the tapered fiber was characterized by using
a scanning electron microscope (sem) and optical microscope. light from a a he-ne laser was
coupled to the untapered end of the tapered fiber to study the distribution of gnrs using the
optical microscope. the effect of different tweezing wavelengths, and the tapered length on the
distribution of gnrs on the tapered fiber surface was investigated. it was observed that the
maximum surface area of tapered fiber was covered with gnrs when tweezed consecutively
with two different wavelengths (1064 nm and 632 nm). the application of the tapered fiber
covered with gnrs as a sers substrate was investigated for a chemical and material,
rhodamine 6g (r6g) and graphite, respectively. furthermore, we presented the tweezing of an
another compound zn (oh)2 on the tapered fiber surface when mixed with gnrs solution using
two lasers consecutively.