Photonics Dictionary

Tip-enhanced Raman scattering (TERS) is a powerful technique that combines Raman spectroscopy with the enhanced spatial resolution provided by a sharp metallic or dielectric tip. TERS allows...

The study of the optical properties of living tissue. Increased understanding of the behavior of light in this varied, turbid medium, especially its scattering and absorption characteristics, is...

The use of a surgical laser instead of sutures or staples to close a wound or rejoin severed blood vessels.

A Ti:sapphire laser is a type of solid-state laser that utilizes a titanium-doped sapphire crystal as the gain medium. The name Ti:sapphire comes from the combination of titanium (Ti) as the dopant...

In the context of optics and lasers, a transverse mode refers to a specific spatial pattern of the electric field within the cross-section of a laser beam. These modes represent the different...

The laser pumping that exhibits an advantage over longitudinal pumping in that the threshold pump power density can be lowered approximately in proportion to the laser length.

Abbreviated TEA CO2 laser. A gas laser that provides shorter pulses and higher peak powers than conventional CO2 lasers. The electrical excitation pulse occurs transversely to the optical axis...

Also known as TEA laser. A coherent optical source with a wide wavelength range in the infrared, visible and ultraviolet that uses an electrical discharge transverse to (across) the optical axis to...

A traveling wave tube (TWT) containing a photocathode and window that, receiving a laser beam, produces a modified photoelectric current that is accelerated and propagated into its helical frame.

A tool used in cutting circular holes around a center. Also, a laser cutter in which the beam moves in relation to the cut surface.

Any form of laser; e.g., a dye laser, having an output that can be adjusted over a wide range of wavelengths. Normally the range is about 70 nm wide.

Two-photon polymerization (TPP) is a technique used in additive manufacturing, specifically in the field of 3D printing. It involves using a focused laser to polymerize a photosensitive material in a...

Twyman-Green interferometry is a technique used in optics to measure the flatness or surface profile of optical components with high precision. It is based on the principles of interference of light...

An ultrafast pulsed laser is a type of laser that emits extremely short pulses of light with durations typically on the order of femtoseconds (10-15 seconds) or picoseconds (10-12 seconds). These...

A laser capable of generating light pulses that last only a few femtoseconds. This can be achieved by nonlinear filtering to increase bandwidth and compress the pulse or by passive mode-locking or...

A pulsed laser having molecular nitrogen as laser material and a wavelength output of 337 nm in the ultraviolet region. It is essentially a channel flashtube in which a pulse is applied to the...

A connection, typically made up of one or more cables, between a laser head and a separate power supply. Flexible pipes or hoses are sometimes used to protect and stabilize multiple cables.

Illumination of hologram facets with a beam that covers only a small portion of the hologram in order to optimize laser energy use. See overillumination.

A device used in a free-electron laser to convert the electron-beam's energy into microwave laser radiation by creating a magnetic field of alternating polarity through which the free electrons are...

Array used in coded-aperture imaging experiments with two-beam CO2 lasers that provide an artifact-free process, faithful reproduction of the true image, and more photon collection than the pinhole...

A resonator often used for mode control in Fresnel number laser cavities that is highly vulnerable to extremely weak external sources of feedback.

A multilayer antireflective thin-film coating, so called because its reflectance rises steeply at wavelengths above and below a narrow band at zero. The v-coat is particularly useful in high-power...

Lasers based on neodymium-doped yttrium or gadolinium vanadate crystals. These include yttrium vanadate (Nd:YVO4), gadolinium vanadate (Nd:GdVO4), and lutetium vanadate (Nd:LuVO4). Vanadate lasers...

See laser Doppler velocimeter; laser velocimeter.

A method of measuring negatively charged phase ions using a color-center or lead-salt diode laser.

A laser that has a surface-emitting semiconductor gain element coupled to an external mirror designed to complete the laser resonator. VECSELs can be electrically or optically pumped. The extended...

A vertical-cavity surface-emitting laser (VCSEL) is a type of semiconductor laser diode that emits light vertically from the surface of a semiconductor wafer. VCSELs are commonly used in various...

Vibrational spectroscopy is a type of spectroscopy that involves the study of the vibrational states of molecules. It is used to obtain information about the molecular structure, bonding, and...

A type of change in the energy levels of molecules in a laser that results in lasing action. Vibronic transitions are those between one electronic level and another.

A disc whose surface contains recorded digital data at high-packing densities arranged in concentric rings. The data, representing video frames, are both recorded and read by a laser beam.

An instrument that uses an erbium:glass laser to determine cloud height from the ground.

Volume Bragg gratings (VBGs) are specialized optical elements that consist of periodic variations in refractive index throughout the volume of a transparent material, typically a photosensitive glass...

Volumetric imaging refers to the capture, visualization, and analysis of three-dimensional (3D) information from a volume of space. Unlike traditional two-dimensional (2D) imaging, which provides...

Gas laser in which the tube acts as a channel for the laser beam.

Whispering gallery mode (WGM) refers to a phenomenon in wave physics, particularly in optics, where waves, such as light or sound waves, are trapped and circulate along the periphery of a curved...

An extremely wide emission spectrum generated by the nonlinear effects created when a high peak power from a short-pulse laser is focused into a water or carbon tetrachloride cell. The resulting...

A high-intensity source of incoherent white light in which a capacitor is discharged through a tube of xenon gas; often used as a source of pumping radiation for various optically excited lasers.