Laser construction

Résumé

A laser is constructed from three principal parts: *An energy source (usually referred to as the pump or pump source), *A gain medium or laser medium, and *Two or more mirrors that form an optical resonator. Pump source The pump source is the part that provides energy to the laser system. Examples of pump sources include electrical discharges, flashlamps, arc lamps, light from another laser, chemical reactions and even explosive devices. The type of pump source used principally depends on the gain medium, and this also determines how the energy is transmitted to the medium. A helium–neon (HeNe) laser uses an electrical discharge in the helium-neon gas mixture, a Nd:YAG laser uses either light focused from a xenon flash lamp or diode lasers, and excimer lasers use a chemical reaction. Gain medium / Laser medium The gain medium is the major determining factor of the wavelength of operation, and other properties, of the laser. Gain media in different materials ha

Source officielle

https://en.wikipedia.org/wiki/Laser_construction

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (4)

Publications associées

Chargement

Personnes associées

Chargement

Unités associées

Chargement

Concepts associés (12)

Concepts associés

Chargement

Cours associés (4)

Cours associés

Chargement

Séances de cours associées (6)

Afficher plus

Séances de cours associées

Chargement

Fiber lasers are compact lightsources with high intrinsic beam quality and high efficiency. The lasing spectrum ranges from the blue to the near infrared and is achievable using fibers with different dopants and glass compositions. All-fiber lasers are characterized by a high attainable stability and are also available in the pulsed regime. A widespread range of applications for all-fiber lasers exists in the domain of telecommunications as well as in the medical domain. The first part of this work is dedicated to the characterization of fluoride glasses regarding photosensitive effects. Fluoride glasses allow several lasing transitions, which are not available in silicate glasses. Photosensitive effects in fluoride glasses would pave the way to fabricate fiber Bragg gratings in fluoride fibers. Fiber Bragg gratings can act as laser mirrors and are a necessary tool on the way to all-fiber lasers with an output beam inside a fiber tail. In this work, doped and undoped fluoride glasses are exposed to different ultraviolet lasers and induced refractive index changes are investigated by changes of their absorption spectra. Index changes higher than 10-4 have been obtained. The second part is dedicated to demonstrate novel upconversion laser configurations in the visible spectral range using fiber Bragg grating technology in germanosilicate fibers and upconversion in fluoride fibers. Upconversion lasing in the green, orange and red spectral range were demonstrated. Tuning over 8 nm was shown for the orange laser. To minimize intracavity losses, mode field diameter adapter in germanosilicate fibers have been realized. The incorporation of an all-fiber accousto optic phase modulator inside the cavity allows pulsed operation of the upconversion laser. Mode locking is demonstrated at the red wavelength with pulse durations below 100 ps. In conclusion, the potential to fabricate Bragg gratings in Cerium doped and undoped fluoride glasses was demonstrated. Furthermore, green, orange and red lasing of an all-fiber configuration has been shown by a hybrid approach based on fiber Bragg grating technology in germanosilicate fibers and upconversion in fluoride fibers. An all-fiber mode locked upconversion laser in the red spectral range was demonstrated. We believe that such novel upconversion light sources represent a useful tool in different biomedical applications.

EPFL2004

Chargement

ArF laser induced refractive index and luminescence changes in Bi-doped aluminosilicate fibers - INVITED

Christian Ban, Hans Georg Limberger

Fibers doped with bismuth show broad luminescence bands around 750, 1100, and 1400 nm with spectral bandwidths of 100 to 200 nm at room temperature. The luminescence bands can be observed by pumping broad absorption bands in the visible or near infrared spectrum (around 500, 700, 800, 1000, and 1360 nm). Bismuth fiber laser action has been demonstrated using FBG in standard germanosilicate fibers as intra-core laser mirrors. In this work we report about the investigation of refractive index and luminescence changes of Bi-doped silica optical fibers under ArF irradiation. The Bi-doped fibers showed permanent photo-induced refractive index changes of ~2×10-4 and ~2×10-3 for pristine and H2-loaded fibers (Fig. 1), respectively. Such refractive index changes allow fabricating strong Bragg grating fiber laser reflectors directly in these fibers thus potentially improving the laser efficiency. Stress measurements of pristine and irradiated fibers indicate that the refractive index change is related to color centers and compaction for both pristine and H2-loaded fibers. The impact of pulsed 193-nm irradiation from an ArF excimer laser on absorption and luminescence of pristine and H2-loaded bismuth doped fibers was investigated. ArF irradiation increased the absorption strongly. At e.g. 400 nm the values changed from ~2 and ~3 dB/m to ~59 and ~174 dB/m for pristine and H2-loaded fiber, respectively. Light emission under visible Ar+ (454, 488, 514 nm), and Kr+-laser (567, 647, 676 nm) pumping was measured from 600 to1700 nm in a longitudinal arrangement. In all cases a particular strong increase in 1140 nm luminescence was measured for the H2-loaded fiber (Fig. 2). In side measurements under 1053 and 1357 nm pumping, 18 and >16 dB increase of the 1140 and 1400 nm luminescence for the H2-loaded fiber was observed. Decomposition into Gaussian bands suggests that H2-loading followed by ArF irradiation leads to the appearance of new bands in both the absorption and emission spectra.

2010

Chargement

Chip-based soliton microcomb module using a hybrid semiconductor laser

Jijun He, Tobias Kippenberg, Junqiu Liu, Erwan Guillaume Albert Lucas, Arslan Sajid Raja, Nicolas Volet, Rui Ning Wang

Photonic chip-based soliton microcombs have shown rapid progress and have already been used in many system-level applications. There has been substantial progress in realizing soliton microcombs that rely on compact laser sources, culminating in devices that only utilize a semiconductor gain chip or a self-injection-locked laser diode as the pump source. However, generating single solitons with electronically detectable repetition rates from a compact laser module has remained challenging. Here we demonstrate a current-initiated, Si(3)N(4 )chip-based, 99-GHz soliton microcomb driven directly by a compact, semiconductor-based laser. This approach does not require any complex soliton tuning techniques, and single solitons can be accessed by tuning the laser current. Further, we demonstrate a generic, simple, yet reliable, packaging technique to facilitate the fiber-chip interface, which allows building a compact soliton microcomb package that can benefit from the fiber systems operating at high power (> 100 mW). Both techniques can exert immediate impact on chip-based nonlinear photonic applications that require high input power, high output power, and interfacing chip-based devices to mature fiber systems. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

OPTICAL SOC AMER2020

Chargement

EPFL2004

ArF laser induced refractive index and luminescence changes in Bi-doped aluminosilicate fibers - INVITED

Christian Ban, Hans Georg Limberger

2010