Optics and Light Properties

Fluorescence is the emission of light by a substance that has absorbed light. Here, the emitted light has a longer wavelength and, therefore, lower energy than the absorbed radiation.

Phase contrast microscopy is particularly important in biology. It reveals many cellular structures that are not visible with a simpler bright field microscope. These structures were made visible to earlier microscopists by staining, but this required additional preparation and killed the cells. The phase contrast microscope made it possible for biologists to study living cells and how they proliferate through cell division. After its invention in the early 1930s, phase contrast microscopy proved to be such an advancement in microscopy, that its inventor Frits Zernike was awarded the Nobel prize in 1953.

Focusing is the process of adjusting the lens elements so that light rays from a specific point in the scene converge at the same point on the image sensor, creating a sharp image.

The Law of Reciprocity in photography states that the total exposure is determined by the product of the intensity of light (aperture) and the duration of exposure (shutter speed).

Luster describes the appearance of a mineral surface in terms of its light-reflective qualities, such as metallic, glassy, or dull.

Light travels in straight lines, a principle known as rectilinear propagation, unless it is reflected, refracted, or diffracted.

Light is a form of electromagnetic energy. It exhibits wave-particle duality and travels in discrete packets of energy called photons.

Light microscopes use visible light and lenses to magnify specimens, resulting in a much lower resolution (limit of about 200 nm) compared to electron microscopes, which use electron beams and have a much higher resolution (limit of about 0.1 nm).

Reflection is the bouncing back of light waves when they hit a surface. Refraction is the bending of light as it passes from one medium to another, while absorption is when light is taken in by an object.

Optical storage media, such as CDs and DVDs, use laser technology to read data from pits and lands on the disk surface. Laser power is also used to burn or modify the surface during the writing process.

Infrared spectroscopy measures the absorption or reflection of infrared light by a material, providing a unique chemical fingerprint. It is a standard method for identifying fiber composition.

Polarizing light microscopy uses filters to examine the optical properties of fibers, such as birefringence. This helps identify the crystalline structure of the fiber.

Luster is the physical property that describes how light reflects off the surface of a material, often described as shiny or dull.

Light therapy, also known as phototherapy, is the therapeutic use of light rays or waves to treat various skin conditions. Other terms like phoresis refer to the movement of ions through a medium using electricity.

Fluorescent lighting is known for producing cooler, often bluish light tones compared to the warmer, yellow-red tones of incandescent bulbs.