Chinese researchers have reportedly demonstrated a new way to dramatically enhance ultrafast laser interactions without increasing overall laser power. Their findings could potentially open the door to safer and more precise high-intensity optical systems.
In a study published in Nature, researchers led by Jian Wu at East China Normal University made the discovery using a form of quantum light known as bright squeezed vacuum.
Using this, they boosted a key nonlinear optical process by more than 20 times compared to a conventional laser pulse carrying the same average energy.
According to the team, their work tackles one of the biggest limitations in modern laser physics.
At present, many advanced optical effects rely on nonlinear interactions, where multiple photons interact with matter almost simultaneously. This is critical for various fields ranging from attosecond (10-8 seconds) physics to high harmonic generation and ultrafast imaging.
The problem is that nonlinear effects usually require extremely intense laser pulses, which can damage the very materials or systems being studied.
Instead of increasing laser power, the team altered the statistical behavior of the light itself. Unlike standard laser light, where photons arrive at a relatively steady rate, bright squeezed vacuum produces extreme fluctuations in photon density.
This creates short-lived bursts of very high instantaneous intensity even when the overall average energy remains modest. That distinction proved crucial.
To test the idea, the researchers used the quantum light source to trigger tunneling ionization in sodium atoms. In this process, a sufficiently intense electromagnetic field distorts the atom’s potential barrier so strongly that an electron can effectively tunnel out through quantum mechanical effects.
The team found that a bright squeezed vacuum pulse containing just 300 nanojoules of average energy produced the same nonlinear ionization effect as a conventional laser pulse with more than 20 times the effective intensity.
Importantly, the enhancement came without increasing average power, reducing the risk of thermal or structural damage.
The researchers also demonstrated that they could tune the interaction strength by modifying the quantum statistical properties of the light, rather than altering pulse energy itself.
Traditionally, stronger nonlinear effects have required progressively more powerful lasers. This work suggests that carefully engineered quantum fluctuations may achieve similar results with far lower energy costs.
Some very important applications
The findings could prove especially important for attosecond science, a field focused on observing electron dynamics over timescales measured in billionths of a billionth of a second.
Attosecond experiments typically require extreme laser intensities, often pushing materials and optical components close to their damage limits.
By using quantum-engineered light states instead of brute-force power scaling, researchers may eventually gain finer control over ultrafast interactions while reducing collateral damage to experimental systems.
The study also highlights a broader trend in optics and quantum engineering. Rather than treating quantum fluctuations as noise to be minimized, physicists are increasingly exploring ways to use them as functional tools.
While the approach remains highly experimental, the results suggest that the quantum statistical properties of light may become just as important as raw laser power in future generations of ultrafast optical technology.
You can view the study or yourself in the journal Nature.