In the same year, Ye Mao, who was still studying for his doctorate at the University of Michigan, began to take charge of a graduate course independently, focusing on chip-integrated nanofabrication technology, on the recommendation of his mentor. Looking at the classroom students of different colors and countries, and thinking of the Chinese chip by the U.S. "neck" event, standing on the podium to teach the chip integrated nanomanufacturing technology, Ye Mao, more and more heart is not a taste. In the snowy Michigan night, there is an idea in his head came out: "I may be able to do something".
As the idea came up more and more, Ye Mao began to prepare for his return. "I was thinking, since I have mastered the technology of chip-integrated nanofabrication, why should I stay in the United States to speak to foreign students, I should go back to my country and speak to domestic students about this knowledge." After a few bouncing around, in 2020, Ye Mao officially joined the Beijing University of Aeronautics and Astronautics.
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Even though he has already entered his senior years, Yemo's body still maintains the original kind of purity: fearless and unafraid, moving forward without hesitation; traveling with his heart, and settling down as he goes along.
In 2007, Ye Mao entered the School of Materials Science and Engineering at Huazhong University of Science and Technology. During his time at the university, Ye Mao was not a particularly diligent and "obedient" student, and most of his motivation in learning came from his interest in doing what he liked to do. One day, he suddenly developed the idea of "wanting to go abroad to have a look", so he prepared himself for the exams (TOEFL and GRE), and got a scholarship to the University of Michigan to study Master of Mechanical Engineering.
Ye Mao's master's advisor was an Indian who had a significant influence and position at the University of Michigan. When Ye Mao came to his door, he was offered a research job, which offered him a full tuition waiver as well as a research assistant's salary, which was a very good deal. Ye Mao asked his mentor, "My grades aren't the best and my resume isn't the prettiest, so why give me such a good deal?"
Ye Mao's mentor replied that it was because he felt that Ye Mao had his own ideas about this research. Before going to the United States, Ye Mao had already had some exchanges with his mentor, in which he gave multiple solutions to some research problems, and has since left a deep impression on his mentor. "He thought it was a big highlight for me." Following his master's mentor, Ye Mao engaged in work related to biomimetic bone scaffolds using nanobiomaterials and achieved a series of results.
In 2014, Ye Mao originally planned to work straight after graduating with his master's degree. He confessed, "It was actually a very fortuitous thing that I did my PhD." At that time, Ye Mao had just found a job, and by chance met Prof. Yasha Yi, who had just come to work at the University of Michigan, at an academic presentation. Through exchanging ideas, the two collided with a lot of new ideas, and then his doctoral advisor said to him, "We might be able to realize them [these ideas]." With that, Ye Mao gave up a job opportunity that came his way and chose to pursue a PhD in electrical and computer engineering at the University of Michigan.
Ye Mao's main research interests are chip-integrated optoelectronics and chip-integrated nanofabrication. Simply put, the latter serves the former, and in order to make chip-integrated optoelectronic devices, it is often necessary to spend a lot of time and energy on chip-integrated nanofabrication technology. Since 2014, Ye Mao has entered the top U.S. (state of the art) large-scale chip integration laboratory Lurie Nano Fabrication Facility (Lurie Nano Fabrication Facility) to learn silicon-based materials nanofabrication and chip integration technology, and gradually mastered this technology in the subsequent research work.
During his study abroad, Ye Mao conducted in-depth and systematic research mainly focusing on visible band optical superstructured surfaces and superstructured lenses, light grasping nanostructures of medical scintillators, and chip-integrated LIDAR optical phased array (OPA) devices, and achieved a number of important international leading results.
Yemao has developed a process system for designing and manufacturing superstructured lenses based on large-refractive-index silicon-rich silicon nitride, made a breakthrough in the design technology of superstructured lenses and dispersion-free superstructured lenses that can counteract the delay of etching, solved the problems of difficulty in manufacturing the optical superstructured surfaces and superstructured lenses in the visible wavelength band, and the difficulties in manufacturing of the superstructured surfaces and superstructured lenses, such as high cost and the existence of dispersion, and has developed the grating-structured superstructured lenses, linearly-polarized superstructured lenses and superstructured lenses with focusing structure based on visible wavelength band. He has developed integrated photonics devices such as grating-based superstructured lenses in the visible band, linearly polarized superstructured lenses and superstructured lenses with focusing structures; he has developed light grasping nanostructures that can be used in medical scintillator materials, which greatly improves the luminescence efficiency of conventional medical scintillators; for the core polarization component in chip-integrated LIDAR, he has put forward a non-mechanical controllable polarization scheme based on the combination of the optical phase matrix (OPA) and optical superstructured surfaces, which can greatly reduce the size and weight of LIDAR, and also the cost and dispersion. size, weight and cost of the LIDAR. The related results have been published in more than 20 papers in well-known academic journals in the field, and one international patent has been authorized.
Among them, the optical method of designing the focusing structure developed by Ye Mao was featured in the world-renowned technology review "MIT Technology Review" (MIT Technology Review), which pointed out that this technology has an important application prospect in the future of the chip lithography industry (the article title is "Why superstructured lenses are about to bring a revolution in chip manufacturing", "Why superstructured lenses are about to bring a revolution in chip manufacturing"). Why metalens are about to revolutionize chip-making").
After years of studying and researching abroad, Ye Mao's relationship with his mentor was more like that of a friend and a partner, a relationship that he maintains to this day. He and his PhD supervisor are both very idealistic people, always thinking that they can make something to change the world," says Ye Mao. Therefore, their research is very pragmatic, and often consider the feasibility of some cutting-edge technologies for large-scale application in industry, such as research and development of cutting-edge superlens to study how to reduce the cost to achieve mass production.
In constant communication with his mentor and other teachers, Ye Mao has become more and more determined in this perception of value: making good results is not for the sake of issuing papers, not for the sake of merit and fame, but to go to improve people's lives and make the world a better place. "We have been moving towards this goal, when we make the results, often the first time we think, can this be applied? Compared with the same industry, what are its advantages? The ultimate goal of our research must be to make the scientific results benefit humanity and the world." Ye Mao said.
Just like a practice, Ye Mao in the U.S. continue to draw knowledge, increase insights, enhance the ability to quickly grow into a well-known young scholars in the chip manufacturing industry. He said: "The development of the chip integrated nanometer manufacturing process is very laborious, but when you hand-made 40-nanometer, 20-nanometer structures and devices, you understand every detail of the chip manufacturing process, which is a very valuable experience. Now, looking back, it was one of the biggest takeaways from my time in the US."
Even though he had already carved out a niche for himself abroad, Ye Mao's path back to his home country to take a job was still not a smooth one.
After more than seven years in the US, Ye Mao did not know anyone in the domestic academic community, and could only search for jobs online and submit resumes. It is good that at that time, many schools in China had overseas youth forums, and some colleges and universities enthusiastically issued invitations to Ye Mao. So, during the short Christmas vacation in 2018, he went back to China and ran to four colleges at once. But it wasn't a successful trip, and the teachers he ran into at the time seemed to be more interested in the impact factor of the papers on his resume than in some of the nanofabrication technology and device results Ye Mao came up with. That winter was the first time he knew there was such a thing as paper partitioning.
Some people advised Ye Mao to publish more papers in high impact factor journals, and then use them as a stepping stone to get a job in China. After thinking about it, Ye Mao refused. "I may be able to do so, but this is not my original intention of doing research, the value of the research results is whether it can promote the progress of its field. I think research that can really solve problems and can really be applied is good research." Even though there was little to gain from that brief return in 2018, Ye Mao persisted with the idea of going back to China. After graduating with his PhD, he continued his postdoctoral research for a year to finish the work he hadn't completed before, and returned to the country again at the end of 2019.
This time, Ye Mao met the "Bole" who understood him - Academician Fang Jiancheng. After some in-depth exchanges, academician Fang Jiancheng told him, "Your research is good, we need talents like you to do chip-integrated optoelectronic devices and nano-fabrication technology. Compared with thesis, we are more interested in the results that can be practically applied, can solve the problem, and can be really useful and good use." In this way, Ye Mao joined the Beijing University of Aeronautics and Astronautics, as an associate researcher.
"To do research, you need to find like-minded people, and I share the same idea with Academician Fang, which is to make something practical and useful. Compared to sending articles, we care more about whether we can make the chip integration business, make China's own chips in their own fields and put them into industrialization, change the pattern of the chip industry, so that China's chip business to catch up with, or even catch up with the United States." Ye Mao said.
Compared to the design of the chip, the chip manufacturing is the key constraints on the development of China's chip integration business "short board". How to chip the optoelectronic devices, do so small while also reducing costs, have a perfect function, good performance, high yield, is a larger problem, and Ye Mao in order to solve this problem and return.
Using years of research accumulation in the field of chip-integrated optoelectronic devices, and facing the national demand for the development of key measurement and navigation instruments, Ye Mao immediately carried out research on the theoretical methodology and fabrication technology of chip-integrated quantum precision measurement devices after his return to China, mainly including chip-integrated atomic magnetometers, chip-integrated atomic gyroscopes, functional optical superstructured surface technology, and commercially available planar integrated optical superstructured lenses. Integrated Optical Superstructure Lens, etc., which is committed to providing strong technical support for China to realize the breakthrough of core key optoelectronic chip technology in a short period of time. At the same time, Ye Mao also relies on the development of national major scientific research projects to carry out the relevant platform construction and teaching work.
Engaged in scientific research results for many years, Ye Mao rarely have negative emotions. Looking back on his own all the way, he said, "There are problems to solve the problem, I actually do not have so much time and energy to solve the emotional things."
When he was in the US, although Ye Mao's team had a lot of resources, there were very few people on the team, only two PhDs, him and his junior. During those years, it was the two of them who accomplished one scientific study after another. In the process of making chip-integrated optoelectronic devices, all kinds of problems would arise. But without a word of complaint, Ye Mao and his senior brother just buried their heads in their work, and eventually completed a number of scientific research tasks with strict engineering specifications. "In fact, we didn't feel very tired, that is, on the one hand, we have a plan to do research, on the other hand, we think out of the box to think more and try more. We don't have time to think: this is so hard, what if we can't do it? Or, this is too hard, don't want to do it. This is not possible, since we started to do it, we must do it, and do it well."
When he returned to China, although he was not recognized at first, Ye Mao never thought of giving up. He thought or: what problems can be solved, as long as I make the results, and can be used, one day someone will recognize. It is this optimism and resilience that has made Ye Mao what he is now.
The atomic magnetometer based on the atomic spinless exchange relaxation (SERF) effect is currently the highest precision magnetic field measurement sensor, with theoretical accuracy up to the sub-feet scale, and is currently the core device in the strategic magnetic measurement and medical biomagnetism equipment. Chip-based atomic magnetometers will greatly reduce the current device size (from the traditional centimeter scale to millimeter or even micrometer scale), reduce power consumption and cost, and is the way to go for future high-precision, miniaturized, array-type quantum magnetic sensor devices. A variety of military as well as medical equipment such as miniature quantum navigation systems, miniature deep-sea dive systems, high-resolution magnetic brain imaging devices, and in vivo interventional biomagnetic measurement devices, etc., all put forward an urgent need for chip-based atomic magnetometers.
In 2014, Sandia National Laboratories, supported by the U.S. National Institutes of Health (NIH) and the U.S. Department of Energy's Nuclear Security Administration (DOE-NNSA), initiated the development of the principle prototype of microchip-enabled SERF atomic magnetometer arrays (OPM). In addition, the U.S. National Institute of Standards and Technology (NIST) has been funded by the U.S. Strategic Environment and Development Research Program (SERDP), and in recent years, it has developed the principle prototype of vertically bonded atomic magnetometer applicable to chip-integrated manufacturing method, and taken the lead in the research of chip-integrated atomic magnetometer. At the same time, China has also clearly put forward the urgent demand for chip-integrated quantum precision measurement devices in the "14th Five-Year Plan". The core of the chip-based atomic magnetometer is to solve the problem of photonics manipulation and coupling in the chip-integrated atomic magnetometer, which is a micro-nano photonics, chip-integrated nano-fabrication and quantum precision measurement of multi-disciplinary crossover neck problem.
In order to solve this technical challenge, Ye Mao applied for the Natural Science Foundation of China Youth Science Fund project, "Research on Photonics Manipulation and Coupling Problems in Chip-integrated Atomic Magnetometers". In the project research, he will explore the chip-scale micro-miniature atomic magnetometer in the precise optical manipulation method, light/quantum coupling mechanism, on the basis of which the development of integrated photonics manipulation and coupling for the chip-based atomic magnetometer, and finally combined with the micro-atomic system integrated light/quantum coupling very weak magnetic measurement experiments, in order to realize the chip integrated atomic magnetometer from scratch to lay the foundation of a breakthrough.
The solution of photonics manipulation and coupling in chip-integrated atomic magnetometer is the first step to break through the existing bottleneck and develop a high-precision, array-type, integrated precision quantum measurement system, and it is also the first step to realize the urgent needs for high-resolution magnetic brain imaging, deep ocean/deep earth magnetic exploration, and the development of a chip-integrated quantum measurement system, which are essential for the realization of the national "14th Five-Year Plan". The first step is to realize the urgent needs of high-resolution magnetic brain imaging, deep ocean/deep earth magnetic detection, and the core problem of chip-based quantum measurement system.
In terms of applications closer to people's lives, Ye Mao also mentioned: "For example, we have gyroscope sensors in our cell phones, and although they are sufficient for people's lives, they are not yet ideal. If the quantum gyroscope to chip, the phone's navigation and positioning will be more sensitive and accurate. At present, most of the automatic driving system relies on LiDAR as the core ranging sensor, but now the radar is still relatively large, can only be placed on the roof of the car, if we do the chip, not only can reduce the volume, but more importantly, to reduce the cost, so that a car can be installed with a number of different dimensional scanning of the chip-integrated LiDAR, so as to make the automatic driving more accurate and safe."
At present, the relevant work is being carried out in an orderly manner. Ye Mao said, the meal to eat one bite at a time, the road also need to take one step at a time. Making China's own chips is not a quick fix, but he is willing to work hard for this goal.
In addition, Ye Mao to the nation's top chip integration ultra-clean room laboratory Laurie nanofabrication technology laboratory as a template, dedicated to the construction of chip integration ultra-clean room laboratory system. Chip integration ultra-clean room laboratory is an important experimental manufacturing platform in the direction of microstructures and microsystems, which can play an important role in supporting the future of the entire electronics, electrical, mechanical, materials, biological and optical disciplines. However, the construction of the platform is a long-term project, the initial goal is to build a hundred level of ultra-clean room and gas purification internal circulation system, personnel management and use of the system is the main. 5 years of the expected goal is to be able to manufacture their own nanostructures in the laboratory beyond the accuracy of China's current industrial chip.
"After returning to China, I found that the domestic chip development has been hot. Like a spring, many laboratories for manufacturing chips have been built. However, relatively speaking, there is a lack of professional equipment debugging, maintenance and process development and other related talents in China." Although the construction of the laboratory has been on the agenda, but in the preliminary study, Ye Mao proposed to temporarily use the domestic construction of the public **** nano-fabrication platform. He said, "Because the country has spent a lot of money on building chip manufacturing labs, we need to fully utilize them. Compared with some mature labs in Europe and the United States, they may not have enough process accumulation, but the equipment is still very good. We can cooperate and use the overseas process experience to carry out research and development together to improve the precision and achieve a benefit maximization."
At the same time, Ye Mao also said, in order to technology independent and controllable, definitely need to establish their own laboratories, but before that, first of all, to train or introduce a number of related personnel, and so build a good mature talent reserves and management system, in order to better help the construction of the experimental platform.
In Beijing University of Aeronautics and Astronautics, Ye Mao proposed to open a full English chip integration nanomanufacturing course. This course is still relatively rare in domestic schools, even in the United States, only a few universities with excellent conditions have opened. However, the trend of the whole industry for electronic and optical devices is moving towards miniaturization and miniaturization, so chip-integrated nanofabrication technology is not only used to fabricate chips, but is also the way to fabricate new nanostructures/devices with multiple functions. This technology is bound to become more and more popular in the future. Relying on the experience of teaching this course in the U.S., Yemao hopes to make domestic students more aware of this technology by offering this course, and to train more talents in chip-integrated nanomanufacturing for China.
For his students, Ye has his own requirements and expectations. First, he hopes that students have a strong heart, not because the research work is difficult to avoid, or even give up, to have indomitable spirit; second, he hopes that students can make the research process a little happier, to enjoy the process of scientific research. "Experience is the most valuable treasure, even if you don't do this thing in the end, but the process has accumulated a lot of valuable experience. If you don't try and explore, how can you gain experience? I still say, there are problems to solve the problem, do not go to escape, do not give up, to have the spirit to make it work."
Play basketball, learn the guitar, follow the short video to practice a handful of good cooking ...... After work, Ye Mao is also very serious in life. Whether it is work, or life, he maintains his own rhythm, not arrogant and not impatient. For the future, Ye Mao does not do too much envisioning, will not be anxious because of the unknown, in his case, the only clear thing to do, is to grasp the moment, hard work, fully committed to their love of scientific research.