opticalimaging

Optical imaging is a set of techniques that generate images by detecting light interacting with matter. It encompasses a broad range of methods that use visible, near-infrared, or other wavelengths to capture information about the structure, composition, or function of objects. Optical imaging relies on detection of transmitted, reflected, scattered, or emitted light, and often records either intensity, phase, or spectral properties.

Key modalities include wide-field imaging and microscopy, such as bright-field, dark-field, and fluorescence imaging; optical coherence tomography for cross-sectional imaging; and various forms of confocal and multiphoton microscopy. Super-resolution approaches like STED, PALM, and STORM overcome diffraction limits in fluorescence. Other techniques rely on phase contrast or differential interference contrast to visualize transparent specimens. In practice, detectors such as CCD and CMOS cameras or photodiode arrays convert light into electrical signals.

Applications span medicine and biology (histology, in vivo imaging, ophthalmology, oncology), materials science (semiconductor inspection, nanostructure characterization), and astronomy. In medicine, noninvasive optical imaging tracks tissue structure, blood flow, or molecular processes using fluorescence or intrinsic contrast. Optical coherence tomography, endoscopy, and near-infrared spectroscopy are notable clinical tools.

Advantages of optical imaging include high spatial resolution and nonionizing illumination, enabling real-time visualization. Limitations involve limited penetration depth in scattering media, dependence on optical access, and potential phototoxicity or photobleaching with prolonged exposure. The field continues to evolve with advances in light source technology, detector sensitivity, and computational reconstruction.