Hi1060

The optical microfibers were drawn from conventional SMF (HI1060, Corning) via the traveling-stage taper-drawing scheme as described elsewhere^{34 (link),35 (link)}. The optical microfiber waist with a uniform diameter of about 1.0 μm and a length of 25 cm was continuously connected with SMF pigtails via adiabatic tapering regions with a length of about 8 cm. The as-fabricated microfiber as well as the tapering regions were kept straight and sealed inside a plastic box to prevent possible damage and air pollution.
We measured the group delay dispersion (GDD) of the as-fabricated optical microfibers using the white-light interferometry^{36 (link),37 (link)}. The relative phase delay was obtained according to the recorded interference spectrum and amplified spontaneous emission (ASE) background by a Fourier transform-based phase retrieval technique, shown in the inset of Fig. 1(b), and the GDD and β₂ can be inferred from this relative phase delay.

Instead of using physically different fibers for the final dispersion (Fig. 2), we use a variant that is much more robust from the experimental point of view. As can be seen in Fig. 6, the two output pulses of the polarizing cube beam-splitter are sent in the same fiber, in opposite directions. Finally, two beam-splitters (BS) extract the two pulses, which are sent to a fast balanced photodetector. This technique (which reminds the idea of the Sagnac loop) permits to obtain the same path on the two laser pulses even when the fiber optical length fluctuates.
The L₂ fiber is an HI1060 from Corning with 2 km length (and an overall attenuation of the order of 3 dB). and the beam-splitters are chosen to have low polarization-dependent losses (Newport 05BC17MB.2). This choice for L₂ leads to stretched pulses of ≈4.5 ns, and 1.35 mW peak power is typically dectected in each balanced photodetector channel input.

Various types of fibers can be used in AFMOTs. In our experiment, we have used 3 fiber types, which are the cleaved single-mode fibers at 974 nm (HI 1060, Corning), the lensed single-mode fibers at 974 nm (TLF SM1060, Nanonics Imaging Ltd), and the cleaved multimode fibers at 974 nm (SMF 28, Corning). The experiments, including the interrogation of cell deformability (Figs. 2, 3) and the optical trapping of spherical particles (Fig. 4b–d), were carried out by AFMOTs with cleaved single-mode HI 1060 fibers. AFMOTs with lensed single-mode fibers were used to trap red blood cells from a rat. Optical trap calibration, as shown in Fig. 4i, j, was carried out by fiber-based detection (see “Fiber-based detection and calibration”) using the AFMOTs with cleaved HI 1060 and lensed TLF SM1060 single-mode fibers, respectively. It is noted that experiments of 3D trapping, cell interrogation, and optical trap calibration from AFMOTs with single-mode cleaved HI 1060 fibers were also carried out in the AFMOTs with SMF 28 fibers (results not shown), and their results are comparable.