Magnetically driven micro-optical choppers fabricated by two-photon polymerization

Abstract

In this Letter, a series of magnetically driven micro-optical choppers based on customized photoresist were fabricated by two-photon polymerization (TPP) technology. Synthetic Fe3O4 nanoparticles (NPs) were modified and dispersed in the original photoresist to achieve magnetic field response. After accurately formulating a magnetic photoresist containing Rhodamine B to reduce the light transmittance, four micro-optical choppers with different slot widths were printed using optimized processing parameters. The micro-optical choppers were remotely manipulated to rotate by the external magnetic field. More importantly, the function demonstration of the micro-optical choppers with an excellent chopping effect was achieved at a given light wavelength of 515 nm. The magnetically driven micro-optical choppers provide a new approach, to the best of our knowledge, for the fabrication of external field-responsive optical components.

Magnetic‐Driven Micro‐Gear Pair Fabricated by Femtosecond Laser Writing

“…The resulting oleic acid‐modified Fe 3 O 4 NPs underwent vacuum‐drying at 60 °C for a period of 12 h. Detailed synthesis steps and the characterization of magnetic NPs can be found in our prior work. [ 40 ] To prepare the magnetic photoresist with 2 wt% Fe 3 O 4 NPs, an initial step involved dissolving 10 mg of OA‐Fe 3 O 4 NPs in 80 μL of n‐hexane and subjecting them to 1 min of ultrasonic mixing. Then, 485 mg of commercially available photoresist SZ2080 (Institute of Electronic Structure and Laser, Greece) and 5 mg of photoinitiator 4,4′‐bis(diethylamino) were added under ultrasonic stirring, carried out at room temperature and in darkness for 30 min.…”

“…[ 34 ] In contrast, other researchers doped magnetic NPs into the non‐magnetic photoresist and fabricated the hybrid magnetic micro‐machines directly by TPP using the special magnetic photoresists. [ 39–42 ] It can be found that magnetic characteristics obtained by this method are more uniform and stable. The judicious application of magnetic photoresists for moving components greatly streamlines the fabrication process for complex mechanical systems.…”

“…Furthermore, the selective use of magnetic photoresists for moving components brings great convenience to the processing of complex mechanical systems. There are a few studies on simple rotational microstructures around an axis, such as micro-turbine, [34,43] micro-filter, [41] micro-optical choppers, [40] and so on. Nevertheless, for complex moving micromechanical systems, multi-step machining is also faced with great challenges.…”

Four-Dimensional Micro/Nanorobots via Laser Photochemical Synthesis towards the Molecular Scale

“…After the introduction of versatile shape-programming strategies and the driven mechanisms of the 4DM/NRs, determining a method to predict and apply 4DM/NRs has grasped our attention [ 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 ]. To enhance the control over shape transformations while minimizing response time, researchers have been exploring nanofabrication approaches with sophisticated designs.…”

“…However, the shape-mutation-induced functional changing brings the fifth-dimensional 5D ability of optical functions into the 4DM/NRs. The 4DM/NRs possess 5D biomimetic functions of sensory function [ 109 , 110 ], chameleon-like coloration [ 111 , 112 , 113 , 114 ], dynamic optical devices [ 115 , 116 , 117 , 118 , 119 ] with variable focus, information encoding/transmission [ 120 ], wettability tailoring [ 121 ], and even electronic skin [ 122 ]. The typical 5D optical devices can be represented by color-shifted photonic crystals [ 18 ] or smart biomimetic compound eyes [ 118 ].…”