Laser fusion research

To solve the energy and environmental challenges on the planet

Energy is one of the challenges that must be solved in today's society. At present, more than 80 % of Japan's primary energy comes from fossil fuels, but there is a limit to the energy resources on Earth. Globally, energy consumption (primary energy) continues to increase with economic growth. On an oil equivalent basis, it continued to increase at an average annual rate of 2.4 % from 3.7 billion tons in 1965, reaching 14.2 billion tons in 2021.

"What is primary energy?"

This is the energy that can be obtained directly from nature, such as oil, coal, natural gas, hydropower, nuclear power, wind power, geothermal power, and solar power.

■Japan's supplies of primary energy

■Years of future availability of world energy resources

■Global energy consumption (by region, primary energy consumption)

Under these circumstances, laser fusion, which can extract energy from hydrogen isotopes inexhaustible in seawater, is expected to be the key to solving global energy problems.

Power generation using laser fusion also is expected to contribute to solving environmental problems such as global warming because it emits no carbon dioxide or nitrogen compounds.

Hamamatsu Photonics is engaged in a variety of R&D activities with the aim of establishing laser driver technology for fusion reactors that will form the core of laser fusion power generation. We also aim to apply the laser technology developed through these efforts to various industries and implement it in society. We continue to take on the challenge of not only working in the energy and environment field, but also in a multifaceted effort to contribute to society, the environment, and humankind.

Creating the Sun on the ground

Star glow and fusion

The light of a star shining in the night sky. In fact, the light is generated by a fusion reaction. A nuclear fusion reaction occurs at the center of a star, and the star is shining from the enormous energy generated there.

The sun, which is a source of various benefits to us, is also generating energy through nuclear fusion reactions. This was revealed by the U.S. physicist Hans Bete (Nobel Prize winner for Physics).

Principle of nuclear fusion

Nuclear fusion is a reaction in which two nuclei that are used as materials are fused together to form a heavier nucleus, at which time very large energy is generated.

In laser fusion, deuterium and tritium are used as fuel. The fusion reaction, in which the nuclei of deuterium and tritium are fused and helium and neutron are produced, produces enormous energy.

If we can create energy by nuclear fusion with human hands, we can create a small sun on earth.

Clean energy that contributes to sustainable development of mankind and society

Deuterium, a material for laser fusion, can be almost inexhaustibly taken from seawater. It is said that the content of deuterium in seawater is about 0.015 %, and theoretically more than 3 billion years.

The energy obtained from deuterium (0.6 g) in one polyethylene tank (20 L) of seawater is equivalent to 250 polyethylene tanks of oil. In other words, a large amount of energy can be produced from a small amount of fuel.

Power generation using laser fusion has the merit of generating less radioactive waste than nuclear power generation by nuclear fission. Nuclear power generation generates high-level radioactive waste such as uranium, but laser fusion power generation does not generate high-level radioactive waste, and only low-level radioactive waste that can be processed and disposed of by conventional technology.

In addition, even if an unforeseen event occurs, nuclear fusion reactors will be shut down as soon as the fuel or power supply is turned off, making it a highly safe power generation technology.

Energy produced by laser fusion power generation, which emits less radioactive materials and emits no carbon dioxide, will be a clean energy that contributes to safer and more sustainable development.

World's first successful cultivation of rice in a plant factory using a semiconductor laser

We have been conducting research and development on laser fusion for a long time since the 1970s to the present, and laser development technology, which is triggered by laser fusion, has produced unexpected results such as plant cultivation experiments using semiconductor lasers.

In 1997, we succeeded for the first time in the world in artificial indoor cultivation of rice by using high-power semiconductor lasers instead of sunlight. 680 nm laser was used for the experiment. The chloroplast of rice was most active in photosynthesis, using the technique we developed for laser fusion. Compared with the conventional method of cultivation at the Plant, it is also possible to reduce the cost of electricity and shorten the cultivation period, indicating the possibility of eliminating food shortages worldwide in the future.

In 2000, we began cultivating sakamai and perfected the sake "Hikari no Homare" brewed with the rice.

Artificial indoor cultivation of rice by semiconductor laser

Sake "Hikari no Homare"

These efforts led to the establishment of Hamamatsu PhotoAgri, Inc., a special-purpose subsidiary that engages in research and development related to agriculture and the production of agricultural products, centered on the cultivation of “Richleaf^®”.

How laser fusion power generation works

When a capsule containing fuel (deuterium and tritium) is irradiated with numerous laser beams from all directions in a fusion reactor, the capsule is imploded, causing the compressed plasma with high temperature and high pressure. The deuterium and tritium nuclei in the plasma strongly collide with each other, causing an enormous number of nuclear fusion reactions.

Dozens to more than 100 times more energy is generated in this process than the electric energy used for the laser.By repeating this process continuously, enormous amounts of energy can be generated.

Laser fusion power generation is a system that converts fusion energy into heat and generates electricity.

The process shown above is repeated at a rate of 10 times per second. Fast neutrons generated are absorbed by the blanket on the reactor wall and converted into heat energy. The heat is used to turn a steam turbine and convert it into electricity.

Solving energy problems and creating new laser industries

Photonics technology for realizing laser fusion

In order to realize laser fusion, many photonics technologies are used as elemental technologies, including not only high-power laser devices, which are the key, but also optical measurement technology to capture the fusion reaction and optical technology to control the properties of light.

Our involvement with laser fusion began in the 1970s when we were asked to repair an overseas-made streak camera. In the 1990s, we succeeded in developing a high-power semiconductor laser, which led us to begin full-scale research and development on high-power laser driver for fusion reactor and compact laser fusion power generation. Since then, over the past 30 years, we have continued to take on the challenge of realizing laser fusion in collaboration with governments, research institutes, universities, and companies.

We are also the only private company that is working on not only high-power laser devices but also fuel targets, detectors and measuring instruments such as photomultiplier tubes and streak cameras, all of which are essential for research, using our own technologies.

Our current efforts

High power laser technologies

We are developing laser driver for fusion reactor, designed for use in practical power plant. We are involved in-house in everything from the development of laser amplifiers for even higher output power to the research, development, and manufacture of the laser diode bar modules that are used in these amplifiers.

We will continue to develop semiconductor lasers and high power lasers more optimized for laser fusion reactions.

Generation, measurement and control technologies of high energy density plasma

We are developing a plastic capsule with a few mili meters in diameter containing deuterium and tritium.
This plastic capsule plays an important role in imploding fuel, and high sphericity and uniform wall thickness are required. In addition, Since a single capsule is consumed for each fusion reaction, laser fusion power plant consumes 10 capsules per second, or 300 million capsules per year, requiring mass production technology at low cost.

We are also developing detectors for measuring and observing ultrahigh-speed phenomena in high-power lasers, which are the backbone of laser fusion.

The streak camera for measurement is an ultrafast photodetector that captures the optical phenomena that occur in an extremely short time.

Laser fusion research

We are conducting a variety of R&D activities aimed at realizing laser fusion power generation that takes advantage of the features that enable continuous irradiation of high-power lasers.

Key technologies to generate continuous fusion energy

In order to realize laser fusion power generation, a technology to irradiate a fuel target by laser beams at a 10 cycle per second is required.

This requires technology for stable and precise laser emission at a high repetition rate, as well as technology for continuously supplying a fuel target and directing the laser beam.

Fusion plasma diagnosis and measurement

The technology to measurement shot by shot of fusion reaction generated continuously is also very important.

We have acquired a large amount of data from fusion experiments conducted under various conditions, and by utilizing machine learning, we are aiming to search for conditions that will produce a highly efficient fusion reaction.

・Large amounts of reproducibility data
・Use of database construction and machine learning

Applications that extend beyond

We have been engaged mainly in the development of high-power laser technology to realize laser fusion for more than 30 years, and the technologies and products we have developed in the process have also created new applications