Used terms:

- Single-frequency laser - laser whose output radiation spectrum contains only one frequency. Line width of radiation from such laser is determined by instabilities of the generation frequency value arising because of various external or internal perturbations of the laser resonator (mechanical, acoustic, etc.). Line width of output from a single-frequency laser can be significantly (by one, two, and more orders of magnitude) reduced by using a system of stabilisation of the laser generation frequency. Such a system must include a stable spectral reference, such as a transmission peak of an optical interferometer, atomic absorption line, etc. onto which the laser output radiation is locked. Normally, stabilisation of the laser generation frequency reduces both short-term frequency jitter and its long-term drift. See also: single-frequency lasers

- Computer-controlled tuneable laser system - laser apparatus, in which the wavelength of output radiation can be changed by a computer in a broad range according to a user-specified program. The output wavelength is controlled through spectrally selective optical elements with electro-mechanical drive installed in the laser cavity. Control signals from the computer are fed into these drives through a special hardware interface. For laser wavelength measurement in such systems usually a high-precision fast wavelength meter is included. See also: tunable laser, tunable lasers (book), tunable lasers

- Femtosecond laser - laser generating ultra-short light pulses. As a rule, such pulses are generated in mode-locked regime at a high repetition rate in the range of 1 MHz - 3 GHz. Femtosecond pulses with durations of dozens and hundreds of femtoseconds can be available both from solid-state and all-fibre lasers, as well as from hybrid fibre/bulk laser systems. Owing to relatively high peak output power of femtosecond pulses they can be quite easily spectrally transformed with different methods of non-linear optics (parametric generation, second-harmonic generation, etc.). See also: femtosecond lasers, ultrashort pulse

- Titanium-sapphire (Ti:Sa) laser - solid-state laser, in which a sapphire (Al₂O₃) single crystal containing a certain amount of titanium-ion impurities (Ti³⁺) is used as its active medium. Such lasers feature very broad working spectral range (690-1100 nm). Ti:Sa laser requires powerful optical pumping in the visible green spectrum range. An Nd:YVO₄ laser with frequency doubling may be used as a pumping source for titanium-sapphire lasers. See also: Ti:Sapphire laser, Titanium-Sapphire Lasers

- Fibre laser - a laser whose resonant cavity is formed by an optical fibre. Radiation of such laser is entirely or partially generated within this fibre. In implementations where the radiation path is entirely contained in the optical fibre are usually called all-fibre designs. In cases where a part of the radiation path goes through free space or optical elements other than fibres such lasers are called hybrid or fibre/bulk. Fibre lasers are suitable for both generation of continuous radiation and ultra-short (femtosecond, picosecond) light pulses. See also: fiber laser, how fibre lasers work, fiber lasers

- Dye laser - liquid-based laser, in which a solution of an organic dye formed into a fast jet acts as the active medium. Working spectral range of such laser using one dye solution amounts to 50-100 nm, however the whole visible spectrum range can be covered by using different dyes. The most common spectral ranges of dye jet lasers are 550-700 nm and 275-350 nm, the latter being accessible through extra- or intra-cavity frequency doubling of the fundamental output radiation of the dye laser. Modern manufacturing technology and design of dye jet lasers developed at Tekhnoscan provide almost the same level of ease and comfort of operation as with solid-state lasers. Moreover, the Company also offers combined models of tuneable lasers, which can be configured as both dye jet laser and a titanium-sapphire laser. See also: Dye laser, Dye Lasers, dye laser

- Resonant frequency doubler for continuous-wave (CW) single-frequency lasers - laser accessory for doubling of optical radiation frequency by use of a non-linear crystal installed in an independent (external) high-Q optical resonator. Second-harmonic generation efficiency of such doublers is fairly high for CW radiation and reaches 25-40% at the input radiation power of 1 W. Resonant frequency doubler is a very useful addition to a CW single-frequency laser, allowing efficient conversion of its radiation into a shorter-wavelength range. See also: second harmonic generation, frequency doubling

- Autocorrelator - measurement device for determination of duration of ultra-fast (femtosecond, picosecond) laser pulses. An autocorrelator consists of a scanned Michelson interferometer and a non-linear photo-detector. Usually autocorrelation functions taken from laser pulses are recorded and processed in a computer. Autocorrelators manufactured by Tekhnoscan can be used for measurements of both femtosecond and picosecond radiation pulses. See also: autocorrelators, optical autocorrelation, autocorrelators

- Ytterbium fibre laser - laser, in which an optical fibre doped with ytterbium ions serves as the active medium. Mode locking of the output generated by laser "Ytterbius-Master" occurs due to non-linear polarisation rotation of laser radiation as it propagates along the optical fibre. This method offers an advantage over the traditional mode-locking technique using a saturable absorber in allowing substantially higher peak powers and pulse energies in the laser output. The unique design of fibre laser "Ytterbius-Master" provides means to generate both femtosecond radiation pulses and pico- or nano-second pulses with record-high energies. In its all-fibre version this laser only contains fibre optical elements and no bulk optics. Fiber amplifier may also be used for further amplifying power/energy of output laser pulses. See also: ytterbium-doped gain media

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