Topics that shape the future
- Closer look at research results -

In fact, light that is highly quantum, in other words light that has quantum characteristics, has been developed using various technologies up to now. However, as far as I know, it is probably not possible to amplify the intensity of light while maintaining that state. Superfluorescence is an extremely special amplifier, so I thought it would be amazing if we could use this technology to amplify light, and this research was aimed at first clarifying whether this is possible or not.
If successful, it could lead to the development of quantum optical amplifiers in the future, and further down the line, it may be possible to use that light to unlock the secrets of quantum mechanics. I was willing to devote my entire research career to this, but I have now embarked on a long journey where no one has yet reached the goal. The results of this research represent a step up in the ladder that could potentially lead to the future.

One of the reasons why such a thing has not been demonstrated in previous research on superfluorescence is that the experimental equipment has not yet evolved. After reaching its peak around 1980, various experimental equipment has evolved even during the period when superfluorescence research internationally waned somewhat. In this experiment, a pulsed laser device was used, which could only be controlled in units of 1 ns (nanosecond*), but nowadays, devices that can be controlled in units of 1/10,000 of that, or 100 fs (femtosecond*), are available commercially. In addition, the performance of continuous wave lasers has also evolved dramatically. Using these technologies, experiments that were previously impossible have become possible, and this time, by constructing an original device to demonstrate the amplification effect, we were able to derive experimental results. From this perspective, it is believed that the two catalysts that led to this experiment were the focus on the research field of superfluorescence, which at first glance was thought to have been exhausted, and the evolution of laser light source devices that allow us to delve deeper into that focus.

*1ns is <10 to the power of -9> seconds, 1fs is <10 to the power of -15> seconds

If this were corporate research, we would be asked to produce output that would lead to business possibilities, but in the academic world, we can sit down and focus on our research. The students who will be working with me from now on will discover various technologies through their research, and if there are students among them who share their curiosity about the wonders of quantum mechanics, I think that this will be of the utmost value in terms of gaining value from their learning. You can think for yourself about what the quantum world is like, make a hypothesis, devise an experimental device, and see the results with your own eyes. Of course, classroom learning is important, but you can think for yourself through experiments, see with your own eyes, and think again at the end. I feel that our Faculty of Science and Engineering provides the perfect environment for students who are good at this.

The results of this research are limited to the light intensity, which can be measured by the ruler of classical physics. The synchrony of atomic groups can also only be explained by the theory of classical mechanics. On the other hand, since superfluorescence is originally a synchronization phenomenon in the world of quantum mechanics, we need to clarify how the quantum phenomenon of the amplification of laser light in superfluorescence differs from the phenomenon of classical mechanics. Specifically, our next goal is to set up a new device called cold atoms and observe the movement of atoms at extremely low temperatures, so that we can discuss the quantum nature of light.
I believe there will be many difficulties to overcome on the way to achieving this goal, but I expect that this will enable me to conduct even more interesting research than I am doing now.

Quantum has the characteristic of being entangled, where two quanta behave as a pair. As the name suggests, photon pairs refer to a state in which two photons have a quantum mechanical correlation. Various research studies around the world have already shown that in this quantum entangled state, observational results can be obtained that would not occur in classical mechanics. However, as in this research, no one has yet observed what quantum behavior is observed when a photon pair in a quantum entangled state is input to an atomic group that produces hyperfluorescence. In this area, we are considering precisely observing what quantum properties are retained in the light amplified this time.