Overcoming conventional technological limitations to realize high-speed optical coherence modulation at 350 kHz.
Structured light fields possess a wide range of unique and powerful characteristics. By gaining greater control over their optical coherence, researchers can not only reduce the drawbacks linked to excessive coherence but also uncover new capabilities. This enhanced control offers fresh perspectives on how light interacts with matter. As a result, fine-tuning the coherence of these light fields to suit specific uses has become a major area of scientific exploration.
One of the main challenges, however, is that conventional optical modulation techniques typically suffer from slow modulation speeds. This limitation makes it difficult to move optical coherence control beyond the lab and into practical, real-world applications. Developing methods for rapid optical coherence modulation is now seen as a key hurdle to overcome.
Lithium niobate (LN) has long been recognized as a leading material for high-speed electro-optic modulation, thanks to its strong linear electro-optic response (known as the Pockels effect). With recent improvements in the fabrication of lithium niobate films (LNF) and steady progress in microfabrication technologies, scientists have been able to create a wide variety of integrated photonic devices on LNF-on-insulator platforms.
Many optical modulators and electric beam deflectors now rely on this LN-based platform. By applying voltage to the lithium niobate waveguide, researchers can finely and rapidly adjust the phase of the light passing through it. This precise phase control makes it possible to manipulate optical coherence using LNF modulators.
A New Application of LNF Modulators for Coherence Control
Now the research introduces a novel application of LNF modulators for optical coherence manipulation. By designing specific modulation voltages, we achieve precise, high-speed control of the light field’s phase distribution and tailor optical coherence through the superposition of multiple coherence modes.
Our experimental results are consistent with theoretical predictions, and the proposed strategy can also be easily extended to tailor the optical coherence of different special light fields. This strategy paves the way for practical applications of optical coherence tailoring.
Starting from the principle of coherence modulation, the coherence of random light fields is determined by phase distributions. Controlling phases via high-speed modulators enables optical coherence manipulation. The second-order field moment can be decomposed into incoherent superpositions of coherent modes, and the spectral degree of coherence correlates with phase difference statistics, forming the theoretical basis for modulation.
Technical Implementation of the LNF Modulator
The designed LNF modulator is equipped with 64 independent channels, featuring a binary modulation rate of 2 MHz. Its structure comprises a gold electrode array, a Z-cut LN film, and a ground electrode. By applying voltage, it controls the refractive index differences to achieve precise phase modulation.
In order to verify the high-speed optical coherence manipulation capability of the LNF modulator, a one-dimensional Gaussian Schell-model source is selected as an experimental case. Young’s double-slit interference experiments measure far-field fringe visibility, verifying the partial coherence of generated fields. Experimental results align well with simulations, confirming coherent control. The LNF modulator achieves a 350 kHz modulation rate in the 0–2π phase range, far outperforming digital micro-mirror devices.
The research uses LNF modulator voltage distributions to load prescribed wavefront phases, synthesizing random fields with predefined coherence. Compared to traditional methods, this approach significantly improves the modulation rate while minimizing energy loss, paving the way for practical applications in optical imaging, encryption, and information transmission through random media.
The strategy also offers flexibility for tailoring the optical coherence of different special light fields, though current limitations to one-dimensional modulation may be addressed by developing two-dimensional LNF modulators in the future.
Reference: “High-speed optical coherence manipulation based on lithium niobate films modulator” by Xinlei Zhu, Fengchao Ni, Haigang Liu, Jiayi Yu, Fei Wang, Ya Cheng, Xianfeng Chen and Yangjian Cai, 12 June 2025, PhotoniX.
DOI: 10.1186/s43074-025-00176-5
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2 Comments
Structured light fields possess a wide range of unique and powerful characteristics.
VERY GOOD!
Please ask researchers to think deeply:
Can the structured light fields be understood viar topological vortex framework?
Researchers should not have been misled by so-called peer-reviewed publications. The so-called peer-reviewed publications (including Physical Review Letters, Nature, Science, etc.) have had a detrimental impact on the development of physics today. In the physical world they (including Physical Review Letters, Nature, Science, etc.) construct, different particles can be defined as the same particle, and topological vortices and their twin antivortices can be defined as two vortices with completely different spatiotemporal manifolds. What’s even more ridiculous is that two sets of Cobalt-60, which are artificially rotated in opposite directions, can be two mirror images of each other regardless of symmetry. God, demons, angels, and their pet cats have always dominated the highly acclaimed physical world of these so-called peer-reviewed publications.
If researchers are interested in this, please visit https://zhuanlan.zhihu.com/p/1917878197971816654.