As a vital tool for observing the microscopic world, microscopy has been driving scientific research forward since its inception. From the earliest optical microscopes to today's electron and scanning probe microscopes, advancements in microscopy technology have allowed us to glimpse the secrets of cells, molecules, and even atoms. This article explores the working principles, classifications, applications, and future trends of microscopy.

The fundamental principle of microscopy involves magnifying details of observed objects using light or electron beams. Optical microscopes use lenses to focus visible light onto samples, magnifying images through a combination of objective and eyepiece lenses. Electron microscopes, on the other hand, use electron beams instead of light, achieving higher resolution through electromagnetic lens focusing.

Optical microscopes are the most common type, including bright-field, dark-field, and fluorescence microscopes. They are suitable for observing biological samples such as cells and tissues, with resolutions typically around 200 nanometers.

Electron microscopes are divided into transmission electron microscopes (TEM) and scanning electron microscopes (SEM). TEM allows observation of internal structures of samples, while SEM is used to study surface morphology. Electron microscopes can achieve resolutions of up to 0.1 nanometers, making them suitable for materials science and biological research.

Scanning probe microscopes include atomic force microscopes (AFM) and scanning tunneling microscopes (STM). They use physical probes to scan sample surfaces, achieving atomic-level resolution and are widely used in nanotechnology.

Microscopy is used in biology and medicine to observe cellular structures, pathogens, and tissue sections. For example, fluorescence microscopy can label specific proteins, helping scientists study molecular mechanisms within cells.

Microscopy is employed in materials science to analyze microstructures, defects, and properties of materials. Electron microscopes can observe the lattice structures of metals, while atomic force microscopes can study the surface characteristics of nanomaterials.

Microscopy is used to analyze microorganisms and pollutants in environmental samples, helping scientists understand ecosystem changes and the impacts of pollution.

With advancements in super-resolution microscopy, scientists can observe finer structures. Techniques such as STED and PALM have broken the resolution limits of optical microscopy, achieving resolutions below 20 nanometers.

The application of artificial intelligence and machine learning enables microscopes to automatically identify sample features, optimize imaging parameters, and provide more accurate analytical results. For example, smart microscopes can auto-focus, identify cell types, and even predict sample behavior.

Future microscopes may combine optical, electron, and scanning probe technologies to provide comprehensive sample information. For instance, a single microscope could simultaneously capture a sample's morphology, chemical composition, and mechanical properties.