Achieving high-precision 3D printing with 3D femtosecond laser nanoprinting, the "three highs"
The development of many micro and nano devices in the fields of optics, photochemistry, optoelectronics, nanophotonics, and bionics has led to an increase in the importance of 3D micro and nano processing technologies in recent years.
To achieve optimal functionalization of materials and enhance device performance, laserpecker metal engraving 3D micro and nano machining places high demands on processing enterprises in terms of accuracy, dimension, scale, and speed. These challenges pose a great risk and call for the development of traditional methods and means in micro and nano machining. As a response to the need for high precision and efficiency in 3D micro and nano processing, the emergence of information technology research on 3D femtosecond laser nanoprinting has been observed.
3D femtosecond laser nanofrint is a maskless processing technology with 3D, deep nanoscale resolution and arbitrary structural design. There are three highs in 3D femtosecond laser nanoprinting, namely high precision, high design, and high function.
The three technical characteristics of ultra-fast laser are derived from its high-energy pulse, known as the femtosecond laser. This laser has a high energy density of 1013 W/μm2 which is evident in its ability to process with medium laser power. Its processing mechanism for 3D printing differs from previous methods due to two main factors: thermal effect suppression and nonlinear absorption. This is achieved through the ultra-short pulse duration (ten to several hundred femtoseconds) and its unique interaction with matter, resulting in two-photon or multi-photon absorption. Due to the short absorption time, the thermal effect in the scanned area is effectively reduced, making the femtosecond laser comparable to a cold therapy tool. In contrast to continuous lasers, this highly energetic pulse creates a completely different light-matter interaction.
Femtosecond laser processing has the unique ability of nonlinear absorption, allowing for resolutions below 10nm. Its versatile material handling capabilities span from soft polymers to hard materials like metals, semiconductors, and dielectrics. These capabilities also activate a range of physical and chemical phenomena such as ablation, photopolymerization, photoreduction, and photoisomerization. This makes 3D femtosecond laser nanoprinting a powerful technology that utilizes the femtosecond laser as a processing tool with distinct nonlinear features, setting it apart from other methods and allowing for efficient processing of various materials.
Nanoprinting with femtosecond lasers in 3D
Two-photon polymerization utilizes a femtosecond laser to interact with photopolymer, causing the absorption of two infrared photons simultaneously. This quantum process leads to an exciting transition from the ground state to the excited state. The rate of this absorption is directly proportional to the square of the light intensity, indicating that a high light intensity is necessary for two-photon polymerization to occur. This advanced technology, known as 3D femtosecond laser nanoprinting, has various uses in circuit processing and integration.
The development of two-photon polymerization displays key characteristics commonly seen in 3D femtosecond laser nanocurrying technology for enterprise use, including impressive resolution and exceptional 3D patterning abilities. This resolution, which refers to the smallest system characteristics and size of the industrial structure being processed, measures around 10 nm. This is achieved by focusing the femtosecond laser through a high numerical aperture lens, resulting in a small spot with high photon energy density. The method of two-photon polymerization incorporates three nonlinear effects: optical nonlinearity, chemical nonlinearity, and material use nonlinearity. Combining these three aspects effectively allows for deep subwavelength resolution in production processing technology.
A comparison of traditional 3D laser printing with three-dimensional femtosecond laser nanoprinting based on two-photon polymerization. Compared with the previous laser rapid prototyping technology, 3D femtosecond laser nanoprinting technology has a unique two-photon polymerization processing mechanism, high precision, high processing quality, simple function, and easy integration.
In femtosecond laser processing, two-photon absorption technology ensures that the above process can only be realized at the focal point in order to achieve three-dimensional high-precision processing.
A variety of two-photon polymerized materials have been prepared, including proteins, metal nanostructures, metal oxides, carbon materials, and composites. In theory, as long as a set of appropriate photochemical or photophysical mechanisms are established, many materials can be used as processing objects for two-photon polymerization.