In the context of rapid development of modern technology, precision manufacturing technology at the micrometer and even nanometer scales has become the core driving force for breakthroughs in fields such as integrated circuits, photonic devices, biomedicine, and advanced materials. Among them, micro nano laser 3D lithography, as a high-precision and highly flexible additive manufacturing technology, is gradually becoming a cutting-edge tool in the field of micro nano structure processing. It breaks through the two-dimensional limitations of traditional planar lithography, achieving direct writing of complex three-dimensional microstructures, and is known as the "3D printer of the micro nano world".

1、 What is micro nano laser 3D lithography?

Micro nano laser 3D lithography is a super-resolution 3D processing technology based on nonlinear optical effects such as two-photon polymerization (TPP). The basic principle is to use a focused ultrafast laser beam (usually femtosecond laser) to irradiate a photosensitive resin material. When the light intensity at the laser focus reaches a threshold, local two-photon absorption is triggered, which triggers a chemical reaction of the luminescent initiator and causes the resin to polymerize and solidify. Due to the strong nonlinear properties of two-photon absorption, polymerization reactions can only occur within a very small volume at the center of the laser focus, thus achieving processing accuracy far beyond the optical diffraction limit (up to hundreds or even tens of nanometers), and "writing" any three-dimensional structure point by point.

2、 Technical principles and core components

1. Ultra fast laser source

Typically, femtosecond pulse lasers with wavelengths ranging from 780-800 nm are used, which have extremely short pulse widths and high peak powers, facilitating efficient two-photon absorption while reducing thermal damage to surrounding materials.

2. High numerical aperture objective lens

The key to achieving high resolution is to use oil immersed or air high NA (Numerical Aperture) objective lenses for ultra fine focusing of lasers, forming sub micron sized light spots.

3. Three dimensional precision positioning system

By using a piezoelectric ceramic driven XYZ 3D platform or galvanometer scanning system, the movement path of the laser focus in the photoresist can be precisely controlled to achieve layer by layer or point by point construction of complex structures.

4. Photosensitive material (photoresist)

Using photosensitive resins specifically designed for two-photon polymerization, typically containing photoinitiators, monomers, and crosslinking agents. The material needs to have high two-photon absorption cross-section, fast curing response, and good mechanical stability.

5. Computer control system and software

After slicing the 3D model (such as CAD files), a scanning path is generated, and the control software drives the laser and platform to work together to complete automated processing.

3、 Technical advantages and characteristics

1. Ultra high resolution

Breaking through the traditional optical diffraction limit, the processing accuracy can reach 50-200 nm, suitable for manufacturing nanostructures such as photonic crystals, metamaterials, and micro optical components.

2. True 3D machining capability

Not limited by the traditional photolithography process of "layer by layer exposure+etching", it can directly manufacture complex three-dimensional structures such as suspended, spiral, grid, porous, etc., with high design freedom.

3. Non contact processing

The laser is focused from above onto the interior of the material without the need for a mask, avoiding contamination and damage caused by mechanical contact, making it suitable for clean environment applications.

4. Wide material compatibility

In addition to organic photoresist, it can also be used to process hydrogels (used for biological scaffolds), ceramic precursors, metal nanocomposites, etc., expanding the application boundary.

5. Rapid prototyping manufacturing

Suitable for the research and validation of small batch, customized micro nano devices, shortening the research and development cycle.

4、 Main application areas

1. Micro optics and photonics

Manufacturing micro lens arrays, waveguides, photonic crystals, metasurfaces, etc. for integrating optical chips, lasers, and sensors.

2. Biomedical Engineering

Constructing biomimetic tissue scaffolds, microfluidic chips, and cell culture structures for tissue engineering, drug screening, and organ chip research.

3. Micro Electro Mechanical Systems (MEMS)

Manufacturing movable components such as micro gears, springs, and actuators to promote the development of micro robots and intelligent sensors.

4. Advanced materials research

Constructing lightweight and high-strength lattice structures and topology optimized materials for aerospace and flexible electronics.

5. Data storage and security anti-counterfeiting

Utilizing three-dimensional microstructures to achieve high-density optical storage or anti-counterfeiting labels.

5、 Challenges and Future Prospects:

-Develop higher sensitivity photoresist to improve writing efficiency;

-Combining parallel multi beam processing to achieve large-area rapid manufacturing;

-Combining with artificial intelligence to optimize structural design and path planning;

-Promote the miniaturization and localization of equipment, and lower the threshold for use.

Micro nano laser 3D lithography is not only a technological innovation in precision manufacturing, but also a cross platform connecting physics, chemistry, biology, and engineering. It is reshaping our understanding of 'manufacturing', from macro to micro, from two-dimensional to three-dimensional, from mass production to personalized customization. With the continuous maturity of technology, this "micro nano carving knife" will play an increasingly important role in future technology, ushering in a new era of intelligent manufacturing.