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Bioimaging

Bioimaging is an interdisciplinary frontier that integrates optical physics, engineering, and life sciences Grounded in wave optics and information theory, it utilizes high-sensitivity, high-resolution detection systems and intelligent algorithms to study light–matter interactions at fine scales. Its aim is to break the diffraction limit of conventional imaging and achieve multidimensional, dynamic visualization of biological specimens from the nanoscale to the macroscopic level.

Bioimaging leverages a range of innovative techniques—such as super-resolution imaging, three-dimensional tomography, and high-speed in vivo imaging—to unveil the structural dynamics, interaction networks, and functional regulation of cells and biomolecules. These methods allow researchers to observe, analyze, and quantitatively measure physiological and pathological processes with unprecedented clarity, within living systems and under native conditions. While pushing the boundaries of fundamental life sciences, bioimaging also serves as a powerful tool for medical diagnosis and drug development, ushering in a new era of observational biology. However, a persistent trade-off remains: although these imaging approaches can surpass the optical diffraction limit, higher spatial resolution often comes at the expense of temporal resolution and increased photodamage. When studying delicate, dynamic structures in living cells, researchers still face difficult compromises among spatial clarity, imaging speed, and long-term sample viability. Thus, developing next-generation super-resolution technologies that simultaneously deliver high spatiotemporal resolution and low phototoxicity remains one of the most critical challenges in the field.

Structured Illumination Microscopy

Structured Illumination Microscopy (SIM) is a super-resolution imaging technique that combines specialized illumination strategies with computational reconstruction to surpass the optical diffraction limit. Its core principle involves illuminating the sample with structured light patterns, typically sinusoidal stripes, which encode high-frequency spatial information into the captured images. Through algorithmic processing, this encoded information is decoded to reconstruct super-resolved images with more than twice the resolution of conventional widefield microscopy. In SIM, laser light is modulated by components such as spatial light modulators into a series of high-contrast fringe patterns projected onto the specimen. Interaction between the structured illumination and the sample generates moiré fringes, effectively “folding” high-frequency details into a detectable lower-frequency range. By capturing multiple raw images with varying phase shifts and reconstructing them in the frequency domain, the system separates and realigns the aliased spectral components to produce wide-field, high-speed super-resolved images with lateral resolution of approximately 100 nm. Notably, SIM offers relatively low phototoxicity and photobleaching, supports various fluorescent probes, and maintains a favorable balance among resolution, speed, and cost. While its absolute resolution may not match that of techniques such as STED or STORM, SIM has emerged as a powerful tool for studying dynamic biological processes—including organelle interactions and cytoskeletal dynamics—in living cells, particularly where sustained imaging under physiological conditions is essential.

From：Spectral compressive structured illumination microscopy[J].Optics and Lasers in Engineering, 2025, 190(000).Huang Z , Yao Y , He Y ,et al

Stimulated Emission Depletion Super-resolution Microscopy

Stimulated Emission Depletion (STED) super-resolution microscopy is a point-scanning technique that physically compresses the fluorescence emission region to overcome the optical diffraction limit. The system integrates two laser beams within a confocal optical path: an excitation beam that activates fluorescence emission, and a co-aligned, doughnut-shaped STED beam that simultaneously acts on the periphery of the excitation spot. Through the principle of stimulated emission, the STED beam forces fluorescent molecules in the outer region of the excitation spot to return to the ground state non-radiatively, effectively “switching off” their fluorescence. Only molecules located at the central zero-intensity region of the STED doughnut remain capable of emitting light. By adjusting the intensity of the STED beam, the effective fluorescence area can be compressed to a nanoscale volume. The STED beam is typically shaped using a spiral phase plate to generate a vortex beam, which enables precise spatial quenching of peripheral fluorescence. Unlike computational super-resolution methods, STED directly produces super-resolved images without post-processing, offering advantages in imaging speed and suitability for live-cell dynamic observation. However, the technique relies on high-power depletion lasers and demands exceptional system stability. Today, STED has established itself as a key tool for investigating cellular ultrastructure and dynamic biological processes.

From：Hu, Di , et al. "Autofocusing Airy beam STED microscopy with long focal distance." Optics Communications (2017):196-202.

High-sensitivity Single-molecule Localization Microscopy

High-sensitivity single-molecule localization microscopy (SMLM), exemplified by techniques such as STORM and PALM, operates on the principle of temporal separation and precise localization. This approach utilizes high-power lasers (e.g., 405 nm, 561 nm, 640 nm) in combination with specialized fluorescent probes to randomly activate only a sparse subset of fluorescent molecules at any given time, ensuring that the distance between emitting molecules exceeds the optical diffraction limit.The emitted photons are collected through a high-numerical-aperture objective (NA ≥ 1.4) and detected by a highly sensitive camera (EMCCD or sCMOS). The position of each individual molecule is determined with nanometer precision (typically 10–20 nm) via two-dimensional Gaussian fitting. By acquiring tens of thousands of image frames and accumulating all localized positions, a super-resolution image is reconstructed, surpassing the diffraction limit. While STORM and PALM share this fundamental framework, they differ in implementation: STORM typically employs organic dyes whose fluorescence states are controlled by a chemical switching buffer. PALM relies primarily on genetically encoded photoactivatable fluorescent proteins. Both techniques offer extremely high spatial resolution, ranking among the sharpest super-resolution imaging methods available. However, they require stable environmental conditions, including precise temperature control and vibration isolation, to ensure imaging consistency and accuracy.

From：桂丹,商明涛,黄振立.基于sCMOS相机的超分辨定位成像技术[J].中国激光,2018,45(02):206-213.

LBTEK specializes in the research, development, and manufacturing of opto‑mechanical products for bioimaging, offering customers integrated solutions ranging from core components to complete systems. Our products are engineered for real‑world application, delivering outstanding stability, environmental adaptability, and modularity to simplify installation, debugging, and future system expansion.

· In Structured Illumination Microscopy (SIM), LBTEK provides spatial light modulators (SLMs) and digital micromirror devices (DMDs) capable of generating diverse fringe patterns to meet varied structured illumination requirements.

· For Stimulated Emission Depletion (STED) microscopy, our spiral phase plates efficiently convert a TEM₀₀ Gaussian beam into a Laguerre–Gaussian “doughnut” intensity profile, meeting the precise suppression demands of STED illumination.

· In single‑molecule localization microscopy (STORM/PALM), we supply high‑numerical‑aperture objectives for enhanced photon collection, along with dichroic mirrors that enable clean separation of excitation and emission pathways. Additionally, LBTEK offers high‑sensitivity cameras suitable for various point‑scanning optical imaging modalities.

Beyond hardware, we provide comprehensive technical services—including optical design consultation, system integration, hands‑on training, and long‑term technical support—to ensure our customers fully leverage the performance advantages of LBTEK’s bioimaging solutions.