Mode division multiplexing technology for single-fiber optical trapping axial-position adjustment

Abstract

We demonstrate trapped yeast cell axial-position adjustment without moving the optical fiber in a single-fiber optical trapping system. The dynamic axial-position adjustment is realized by controlling the power ratio of the fundamental mode beam (LP01) and the low-order mode beam (LP11) generated in a normal single-core fiber. In order to separate the trapping positions produced by the two mode beams, we fabricate a special fiber tapered tip with a selective two-step method. A yeast cell of 6 μm diameter is moved along the optical axis direction for a distance of ~3 μm. To the best of our knowledge, this is the first demonstration of the trapping position adjustment without moving the fiber for single-fiber optical tweezers. The excitation and utilization of multimode beams in a single fiber constitutes a new development for single-fiber optical trapping and makes possible more practical applications in biomedical research fields.

Single and dual fiber nano-tip optical tweezers: trapping and analysis

“…Single fiber tip tweezers were realized with a micro-lensed cleaved fibers [11], a multicore lensed fiber [12], single-or multi-mode chemically etched fiber tip [13,14] or by gradient index chemically etched fiber tips creating 3D bottle beams [15].…”

A micro particle launching apparatus based on mode-division-multiplexing technology

“…The adjust method of the mode selector is present in Ref [24]. WDM (wavelength division multiplexing) and 1:99 fiber optical coupler and other normal devices are employed to realize the optical path connection.…”

“…The LP 11 mode beam, whose power mainly exists in the middle part of core radius while the LP 01 mode beam, whose power mainly propagates in the center of core [24], therefore we need to mold the fiber tip into a special shape (see Fig.2(a)), which guide the LP 11 mode beam focusing with a large convergence angle to generate the optical trapping force, and simultaneously, guide the LP 01 mode beam not focusing and generating the scattering force to launch the micro particle, therefore a selective chemical etching procedure is developed for fabricating this special tapered fiber tip. The chemical etching solution is composed of 48% hydrofluoric acid (HF), 40% ammonium fluoride (NH 4 F), and de-ionized distilled water.…”

Optical trapping of microparticles using bare fiber nano-tips

“…4 Single fiber tip tweezers were realized with a micro-lensed cleaved fibers, 5 a multicore lensed fiber, 6 single-or multi-mode chemically etched fiber tip 7,8 or by gradient index chemically etched fiber tips creating 3D bottle beams. 9 The measurement of the optical forces acting on the trapped particles is of paramount interest.…”