Magnetic-Field-Driven Reconfigurable Microsphere Arrays for Laser Display Pixels

Abstract

Reconfigurable microlaser arrays are essential to the construction of display panels where the individual pixel should be highly tunable in resonance mode, optical polarization, and lasing wavelength upon external control signals.Here we demonstrate a facile yet reliable approach to fabrication of organic microlaser pixels, in which the assembly of microsphere arrays on each pixel is controlled according to the near-field magnetostatic confinement. The geometrical configuration of diamagnetic microspheres could be readily modulated with the near-field potential traps by using the external field to alternate the saturation magnetization of the underneath micromagnet. The motion of microspheres can be modulated among several states upon applied field, and the reconfigurable microsphere array is thus achieved with high spatial precision and rapid temporal response. Moreover, both isolated and coupled spheres serve as low-threshold microlasers with tunable optical resonance modes, whereas the switching between the vertical and horizontal alignments of coupled spheres manipulates the polarization of lasing outputs. By repeating the magnetostatic confinement on the same substrate, the full-color laser display pixels with magnetically tunable color expression capability are successfully achieved.

Magnetically controlled assembly: a new approach to organic integrated photonics

“…7a ). 204 Benefiting from the size uniformity of the polymeric microspheres and ferromagnetic microstructure used in the assembly process, the control of the magnetic-potential-trap patterns over the states of the microsphere is highly consistent and reproducible. A magnetic hysteresis (M–H) loop of tiny regions on the surface of individual micromagnets was obtained by longitudinal magneto-optical Kerr effect (MOKE) measurements.…”

“…Recently, our group also constructed coupled resonators with highly controllable structures that offer flexibility in tuning the optical resonance modes. 204 Fluorescent dye-doped PS microspheres were first fabricated by the emulsion-solvent–evaporation method as high-quality whispering gallery mode (WGM) resonators. The coupled resonators were then obtained by coupling the pre-fabricated dye-doped PS microspheres on demand using a magnetically controlled assembly method.…”

Miniaturized Laser Probe for Exosome-Based Cancer Liquid Biopsy

“…Recently, active mode optical microresonators with gain molecules have emerged as a powerful tool in the field of laser display, photonic skin, and biochemical sensing, − for example, intracellular microlaser probes generated using dye-doped microsphere resonators. Compared with passive mode WGM microresonators, which require the adoption of an optical coupler (usually an optical fiber, prism, or optical waveguide) and precise tuning to realize light transmission, active mode optical microresonators can generate miniaturized WGM microlasers via free space excitation.…”

Droplet Microfluidic-Based Low-Cost and High-Speed Microsphere Array Direct Writing Technology and Its Applications

“…In recent years, microsphere arrays have been developed for various applications, including microlens arrays, super-resolution imaging, , advanced information storage, anti-counterfeiting, microsphere array electrodes, electrocatalysis, electrochemical capacitors, cell culture, and even the specific identification of a wide range of analytes. , Interestingly, the artificial electric organs that power implanted electronic devices, wearables, and other mobile devices also rely on constructed arrays of microspheres . In conclusion, microsphere arrays can drive scientific advances in optics, electronics, chemistry, biology, and other emerging fields and have become a potentially powerful and essential tool. − …”