Highly Efficient Dual-Fiber Optical Trapping with 3D Printed Diffractive Fresnel Lenses

Abstract

Highly efficient counter-propagating fiber-based optical traps are presented which utilize converging beams from fibers with 3D printed diffractive Fresnel lenses on their facet. The use of a converging beam instead of diverging beam in dual-fiber traps creates a strong trapping efficiency in both the axial and the transverse directions. Converging beams with a numerical aperture of up to 0.7 are produced by diffractive Fresnel lenses. These lenses also provide a large focal distance of up to 200 μm in a moderately high refractive index medium. Fabrication of such diffractive lenses with microsized features at the tip of a fiber is possible by femtosecond two photon lithography. In comparison to chemically etched fiber tips, the normalized trap stiffness of dual-fiber tweezers is increased by a substantial factor of 35−50 when using a converging beam produced by diffractive Fresnel lenses. The large focal length provided by these diffractive structures allows working at a large fiber-to-fiber distance, which leads to larger space and the freedom to combine other spectroscopy and analytical methods in combination with trapping.

Optical Fiber Tweezers: A Versatile Tool for Optical Trapping and Manipulation

“…Additionally, Liu et al proved that the inclined dual-fiber optical tweezers have the ability of 3D trapping, which is related to the inclination angle of the fiber [36]. The combination of 3D printed Fresnel lenses on dual fiber surface was reported to be an excellent method to increase the trapping efficiency and stability [37]. In this scenario, the trap stiffness is increased by a substantial factor of 35-50.…”

Optical trapping and orientation-resolved spectroscopy of europium-doped nanorods

“…Optical trapping of these nanorods has already been reported using beam focusing optical tweezers [24]. Notably, we have previously reported on stable and reproducible optical trapping of dielectric nanoparticles in suspension using our custom-built fibre optical tweezers [25][26][27]. In this context we have studied the trapping of anisotropic NaYF 4 :Er/Yb nanorods in the anisotropic trapping potential of the fibre tweezers [28].…”

High-throughput fabrication of right-angle prism mirrors with selective metalization by two-step 3D printing and computer vision alignment

“…2,3 Typically, 3D printed micro-optics can be based on light refraction, 2 reflection 4 or diffraction. 5 The combination of 3D printed micro-optical elements based on different optical mechanism can easily realize sophisticated optical devices. [6][7][8] Reflective micro-optics offer the advantage of achromaticity, compactness, and the possibility to create broadband polarization phase retarders.…”

“…10 Counterpropagating optical traps are an important optical trapping configuration for the study of living cells. 5,11,12 The concept of such a device is rendered and explained in Fig. 1; two opposing micro-mirrors are printed on standard glass coverslips, to create devices that can be used with any holographic optical tweezers setup and are compatible with advanced microscopies.…”