Laser manufacturing technology has garnered widespread application in fields such as national defense, new energy, and microelectronics, owing to its adaptable material compatibility and high processing precision. However, its advancement has been hindered by the optical diffraction limit, which presents challenges for achieving breakthroughs at subwavelength-scale using conventional optical fabrication methods. The advancement of near-field micro-nano optics has spurred research into evanescent waves and lasers-material interaction mechanisms. This exploration has led to the development of near-field laser super-resolution processing and far-field laser direct-writing super-resolution manufacturing technologies, offering new avenues for laser super-resolution manufacturing.

The primary reason for the existence of the optical diffraction limit is the inability of evanescent waves, which carry high-frequency information about objects, to propagate to the far field. Consequently, research efforts have focused on near-field laser super-resolution processing technologies using methods such as scanning near-field optical microscopy (SNOM) and surface plasmon resonance (SPR) interference lithography. However, these techniques require precise integration between optical field control devices and materials to be processed, resulting in complex processing procedures and stringent manufacturing environment prerequisites, thus limiting their application to near-field scenarios.

Leveraging nonlinear effects during the interactions between lasers and materials offers another pathway for achieving super-resolution manufacturing. Researchers have developed far-field laser direct-writing super-resolution manufacturing techniques based on nonlinear effects including multiphoton polymerization, stimulated emission depletion (STED), and laser-induced periodic surface structures (LIPSS). However, the serial-processing nature of laser direct writing presents limitations in addressing requirements such as large area, uniformity, repeatability, and high efficiency. Hence, there is an urgent demand for a micro-nanomanufacturing solution that surpasses the diffraction limit while offering high throughput, precision, and compatibility with traditional optical micro-nanomanufacturing technologies. Photonic nanojets generated by dielectric microspheres exhibit several superior characteristics, such as subwavelength beam widths and high electromagnetic energies, demonstrating promising potential in the field of super-resolution manufacturing. By utilizing the focusing properties of photonic nanojets and high energy of the focal spot, direct writing can be performed on any material surface and even internally. Consequently, they have attracted significant attention in the field of super-resolution manufacturing.

The control of the optical parameters of single microspheres and incident light sources, along with the microsphere-substrate distance and substrate refractive index, enhances the design flexibility for micro-nanostructure fabrication via microspheres (Fig. 1). This review summarizes the effects of different light sources and microsphere substrate types on super-resolution manufacturing using microspheres (Table 1), compares dielectric microsphere-assisted super-resolution micro-nanomanufacturing with other technologies (Table 2), and outlines the factors that influence the focusing characteristics of a single microsphere (Fig. 2). Furthermore, in multimicrosphere systems, optical coupling effects between microspheres influence the overall optical field distribution and focusing characteristics. Ingeniously designing microsphere arrangements allows for a more complex and diverse control of optical field modes. Additionally, this review summarizes the relevant factors affecting the focusing characteristics of multimicrosphere systems (Fig. 3). Precise adjustments to the microsphere and incident light source positions enable the spatial distribution control of the optical field, facilitating the fabrication of diverse microsphere structures. This not only enhances the understanding of microsphere fabrication, but also expands the application prospects in micro-nano processing, providing a flexible and efficient method for super-resolution manufacturing (Fig. 4). This review summarizes the research progress in microsphere optical field spatial control. Temporal control of optical fields demonstrates significant potential for super-resolution micro-nano processing via microspheres. Accurate control of the temporal characteristics of pulse sequences enables the adjustment of material or microsphere optical properties, thereby achieving precise control over the photon-electron interactions between the microspheres and substrates. This provides a new direction and method for super-resolution micro-nano processing using microspheres, with potential to achieve the efficient fabrication of complex nanostructures. This review illustrates an optimization strategy for the fabrication of microsphere micro-nanostructures based on temporal optical field control techniques (Fig. 5).

Dielectric microspheres have garnered considerable attention in super-resolution micro-nano processing. Through the temporal and spatial control of both microspheres and light sources, photonic nanojets can be tailored to meet specific requirements, rendering them widely applicable in fields such as optics, electronics, and biomedical research. Currently, there are limitations in dielectric microsphere-assisted super-resolution manufacturing via optical, spatial, and temporal modulations. Regarding the spatial control of the optical field, existing research mainly focuses on individually controlling the microspheres or incident light sources, rather than achieving effective integration between the microspheres and incident light sources. This limitation restricts the flexibility and diversity of micro-nano structure fabrication. Future research should emphasize the integration of microspheres and light sources to achieve a high degree of freedom in optical-field shaping for micro-nano structure fabrication. In addition, exploring vector optical field shaping, which involves manipulating both the magnitude and direction of an optical field, may offer new possibilities for super-resolution manufacturing. Regarding the temporal control of the optical field, current research mainly concentrates on the effects of pulse delay and sub-pulse number on microsphere fabrication. Future studies could further investigate factors such as sub-pulse energy ratios and polarization directions to enhance precision control over the micro-nano processing morphology. Furthermore, combining diffractive optical elements (DOEs) and spatial light modulators (SLMs) with optical field modulation and spatiotemporal shaping of microsphere micro-nano processing methods can enable multibeam parallel processing and thus improve processing efficiency. In addition, integrating a mirror scanning system with the spatiotemporal shaping of microsphere micro-nano processing could provide a crucial foundation for achieving cross-scale, high-precision laser super-resolution manufacturing.