Observations of super-Bloch oscillations for optical pulses in a temporal lattice created via two coupled fiber loops, which exhibit collapse with vanishing oscillation amplitude under specific driving strength. Credit: Xinyuan Hu (Huazhong University of Science and Technology
Researchers achieve advances in periodic oscillations and transportation for optical pulses, with potential for next-gen optical communications and signal processing.
Researchers have achieved significant advances in wave physics by conducting experiments on Super-Bloch Oscillations (SBOs), which demonstrate the potential for manipulating optical pulses. By applying both DC and nearly detuned AC electric fields, they not only observed SBO collapse for the first time but also extended these oscillations to arbitrary wave driving situations, paving the way for innovative optical communication technologies.
Wave Physics and Super-Bloch Oscillations
Full coherent control of wave transport and localization is a long-sought goal in wave physics research, which encompasses many different areas from solid-state to matter-wave physics and photonics. One among the most important and fascinating coherent transport effects is Bloch oscillation (BO), which refers to the periodic oscillatory motion of electrons in solids under a direct current (DC)-driving electric field. Super-Bloch oscillations (SBOs) are giant oscillatory motions achieved by applying simultaneously detuned DC- and AC-driving electrical fields. Considered amplified versions of BOs, SBOs receive less attention than ordinary BOs mainly because their experimental observations are more challenging and require a much longer particle coherence time.
One unique feature of SBOs is the existence of coherent oscillation inhibition through an AC-driving renormalization effect, which manifests as the localization of an oscillation pattern with a vanishing oscillation amplitude. Dubbed the “collapse” of SBO, this interesting phenomenon typically occurs in the strong AC-driving regime, which hasn’t been reached in previous experiments of SBOs based on electronic and other systems. All present theoretical and experimental studies on SBOs have been limited to the simplest sinusoidal AC-driving cases, so the SBO collapse under more general AC-driving formats, and the ability to harness SBOs for flexible coherent wave manipulation, also remain unexplored.
Simulated and measured results of SBOs in photonic temporal lattices. (a) SBO oscillation amplitude ASBOs as the function of the ac-driving amplitude Ew and the inverse frequency detuning 1/d. (b) SBO oscillation period MSBOs as a function of the inverse frequency detuning 1/d. The inset figure shows MSBOs as a function of d. (c) Initial oscillation phase of SBOs versus the initial Bloch momentum k for Ew = 1.8, N = 1, j = p/2 and d = p/150. (d)-(g) Measured pulse intensity evolutions for Ew = 1.8, 3, 3.8, and 5.3 under d = p/150. (h) Experimental pulse intensity evolution for Ew = 5.3 and d = p/90. Credit: Hu et al., doi 10.1117/1.AP.6.4.046001
Breakthrough Experiments on Super-Bloch Oscillations
In a recent study, researchers from Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology (HUST), and Polytechnic University of Milan set out to tackle these problems. As reported in Advanced Photonics, by combining both a DC-driving and a nearly detuned AC-driving electric field in the synthetic temporal lattice, the researchers successfully achieved SBOs up to the strong-driving regime. For the first time, they observed the SBO collapse effect and extended SBOs into arbitrary-wave driving situations.
With the flexible controllability from tailoring the synthetic DC and AC electric fields, the researchers observe the features of vanishing oscillation amplitude and flip of initial oscillation direction at specific driving amplitudes, showing the clear signatures of SBO collapse. For a sinusoidal AC-driving, they show that as the amplitude-to-frequency ratio of the AC-driving field takes the root of the first-order Bessel function, the SBO collapse occurs, manifesting as a complete inhibition of oscillation with a vanishing oscillation amplitude as well as the flip of the initial oscillation direction by crossing the collapse point.
Future Prospects in Optical Communications
The characteristic rapid swing features of SBOs and the collapse of SBOs have also been analyzed from the Fourier spectrum of oscillation patterns. By generalizing SBOs from the sinusoidal-driving to an arbitrary-wave driving format, the researchers also observed the generalized SBOs with tunable collapse conditions. Finally, the report exploits the oscillation direction flip feature to design tunable temporal beam routers and splitters.
According to corresponding author Stefano Longhi, professor at the Polytechnic Institute of Milan, “This work realizes periodic oscillations and transportation for optical pulses, which may also find wide applications in versatile temporal-beam control in light routing, splitting, and localization for next-generation optical communications and signal processing.”
Reference: “Observing the collapse of super-Bloch oscillations in strong-driving photonic temporal lattices” by Xinyuan Hu, Shulin Wang, Chengzhi Qin, Chenyu Liu, Lange Zhao, Yinglan Li, Han Ye, Weiwei Liu, Stefano Longhi, Peixiang Lu and Bing Wang, 2 July 2024, Advanced Photonics.
DOI: 10.1117/1.AP.6.4.046001
This work realizes periodic oscillations and transportation for optical pulses, which may also find wide applications in versatile temporal-beam control in light routing, splitting, and localization for next-generation optical communications and signal processing.
VERY GOOD!
Please ask researchers to think deeply:
1. What is the root cause of periodic oscillations for optical pulses?
2. Is wave matter?
3. What is the relationship between waves and particles?
4. Does the spin of topological vortices have periodicity?
5. Is the topological vortex field related to waves?
6. If mathematics is not the language of science, why does science need mathematics?
7. Which the 2D in mathematics and the so-called 2D you observed in scientific experiments are not affected by external factors?
and so on.
Based on the zero viscosity and absolute incompressibility of space, topological phase transitions occur at any point in space to form vortices, which is not difficult to understand mathematically. Once a topological spacetime vortex is formed, it will continue to rotate until it interacts with other vortices to cancel out, annihilate, or change. This is the synchronous effect of topological vortices.
The rotation of topological vortices is spin. Spin generates gravitation. Spin generates energy. Spin generates evolution. Their interaction via synchronous effect is very interesting. Their superposition includes both logical superposition in space-time and factual superposition in reality. Their entanglement includes both surface entanglement and body entanglement. Their deflection methods are endless. In the interaction and balance of topological vortex fractal structures, spin creates everything in the world.
The universe does not make algebra, formulas, or fractions. The universe is a superposition, deflection, and entanglement of geometric shapes, is the interaction and balance of countless topological vortex fractal structures. In these interaction and balance, the past is difficult to change. For the future, some predictable, some unpredictable. But, the present moment is real, certain, and actionable. Physics should not ignore that low dimensional topological fractal structures are the material basis of high-dimensional spacetime.
Scientific research guided by correct theories can help humanity avoid detours, failures, and pomposity. Please witness the exemplary collaboration between theoretical physicists and experimentalists (https://scitechdaily.com/microscope-spacecrafts-most-precise-test-of-key-component-of-the-theory-of-general-relativity/#comment-854286). Some people in contemporary physics has always lived in a self righteous children’s story world. Whose values have been overturned by such a comical and ridiculous reality?
Misguided by the pseudo-scientific theory of Physical Review Letters (PRL), many researchers do not consider the similarities and differences between geometric shapes and physical reality in physics research, but indulge in imagination, and some scholars’ physics research seriously deviates from science, and they are almost unaware of the dirtiness and ugliness. Although mathematics is the language of science, it must be understood correctly.
I hope researchers are not fooled by the pseudoscientific theories of the Physical Review, and hope more people dare to stand up and fight against rampant pseudoscience.
The so-called academic journals (such as Physical Review Letters, Nature, Science, etc.) firmly believe that two high-dimensional spacetime objects (such as two sets of cobalt-60) rotating in opposite directions can be transformed into two objects that mirror each other, is a typical case of pseudoscience rampant.
Scientific research should be respected, but some people in contemporary physics are not. Please witness the actions of certain individuals and publications. If researchers are really interested in Science and Physics, you can browse https://zhuanlan.zhihu.com/p/643404671 and https://zhuanlan.zhihu.com/p/595280873.
The Physical Review journals, encompassing both hybrid and open-access journals, features 17 peer-reviewed publications including Physical Review Letters, Physical Review X, and Reviews of Modern Physics. CP violation was published in Physics Review in 1956. All so-called peer-reviewed publications of Physical Review family are responsible for clarifying this.
CP violation opened the dirtiest and ugliest era in the history of physics.