Researchers Demonstrate Full Amplitude and Phase Control Using Single Phase-Only Spatial Light Modulator
Scientists have demonstrated a method to achieve independent amplitude and phase control of light using a single phase-only spatial light modulator (SLM), a task that previously required two separate devices. The technique splits the SLM into two sequential modulation regions, where the first converts phase retardance into amplitude modulation via a polarizer, and the second corrects the phase offset. This advance offers a more compact and cost-effective platform for applications in holography, structured illumination, and electron-light interaction experiments.
Liquid-crystal spatial light modulators are standard tools for programmable wavefront shaping, but have conventionally been limited to phase-only operation, restricting their use in applications requiring simultaneous control of both amplitude and phase. The new approach, presented by Marius Constantin Chirita Mihaila and colleagues, overcomes this limitation by dividing a single SLM into two functional regions on the same device. The first region introduces a phase retardance that is converted into amplitude modulation by a downstream polarizer, while the second region compensates the resulting phase offset and applies the desired phase distribution. An optical relay images the field from the first region onto the second, enabling coherent complex-field synthesis without a second modulator. The method was validated experimentally through the generation of Bessel-Gaussian beams, helical-phase (orbital angular momentum) fields, and arbitrary focal-plane intensity patterns. By consolidating what was previously a two-device system into one, the platform reduces hardware complexity and cost. The authors suggest the approach is broadly applicable to structured light, holographic displays, and experiments involving electron-light interactions.
What's missing
The study does not report quantitative efficiency metrics (e.g., diffraction efficiency or throughput losses) compared to dual-SLM systems, nor does it discuss limitations arising from the reduced active area available to each functional region when the SLM is split.
What different sources said
- arXiv physicsCenter
Electrically Tunable Heliconical Smectic Superstructure in Polar Fluids
Related
Gut Bacteria Enzyme Found to Break Down Heat-Processed Food Compounds, Producing Novel Biogenic Amines
Researchers have discovered that an enzyme in common gut bacteria can degrade N-epsilon-carboxymethyllysine (CML), a compound formed during thermal food processing, producing previously unknown biogenic amines. The enzyme, ornithine decarboxylase SpeC from enterobacteria, acts on CML and related modified lysine derivatives through a low-level 'underground' catalytic activity. This finding suggests a previously unrecognized communication axis between thermally processed dietary compounds and gut microbial physiology, with potential implications for host health.
Full-Length Gene Sequencing Reveals Two Distinct Bacterial Communities in Black-Legged Ticks Expanding Into Canada
Researchers used Oxford Nanopore full-length 16S rRNA gene sequencing to characterize the microbiome of Ixodes scapularis black-legged ticks collected in Nova Scotia, Canada, distinguishing between tick-adapted bacteria and environmentally acquired bacteria. The study comes as I. scapularis — the primary vector of Lyme disease — is rapidly expanding northward into Canada due to climate change. The findings suggest that environmentally derived bacteria in tick microbiomes are not mere contamination, which has implications for how tick microbiome data is collected and interpreted across surveillance studies.
Study Identifies Metabolic Link Between Cell Envelope Stress and Biofilm Formation in Bacteria
Researchers have discovered that the metabolite acetyl-CoA directly inhibits enzymes that degrade the bacterial signaling molecule c-di-GMP, connecting cell envelope biosynthesis stress to biofilm formation in Pseudomonas aeruginosa. The study found that sub-inhibitory concentrations of antibiotics targeting early peptidoglycan biosynthesis — but not other antibiotic classes — elevate c-di-GMP levels by reducing phosphodiesterase activity, with acetyl-CoA competing for the enzyme active site. Because the relevant enzyme domain is broadly conserved across bacterial species, this checkpoint mechanism may be widespread and could have implications for understanding antibiotic-induced biofilm responses.