Technical Center: Laser Glossary of Terms

TEM

Abbreviation for Transverse Electromagnetic Modes. Used to designate the cross-sectional shape of the beam. The radial distribution of intensity across a beam as it exits the optical cavity.

TEMoo

The lowest order mode possible with a bell-shaped (Gaussian) distribution of light across the laser beam.

Thermal Relaxation Time

The time to dissipate the heat absorbed during a laser pulse.

Threshold

The input level at which lasing begins during excitation of the laser medium.

Transmission

Passage of electromagnetic radiation through a medium.

Transmittance

The ratio of transmitted radiant energy to incident radiant energy, or the fraction of light that passes through a medium.

Tunable Dye Laser

A laser whose active medium is a liquid dye, pumped by another laser or flashlamps, to produce various colors of light. The color of light may be tuned by adjusting optical tuning elements and/or changing the dye used.

Tunable Laser

A laser system that can be "tuned" to emit laser light over a continuous range of wavelengths or frequencies.