Injection-locked single-frequency laser with an output power of 220 W

Abstract

A solid-state laser system for the next generation of gravitational wave detectors with an output power of 220 W at the wavelength of 1064 nm is presented. Singlefrequency operation of the laser was achieved by injectionlocking of a high-power ring oscillator to an amplified nonplanar ring oscillator (NPRO) following the Pound-DreverHall scheme. The high-power stage which features four longitudinally pumped Nd:YAG laser crystals as active media in a ring resonator configuration was designed for reliable long term operation. Using a non-confocal ring cavity to filter the output beam, a pure TEM 00 mode with 168 W output power was obtained.

Stabilized high-power laser system for the gravitational wave detector advanced LIGO

“…1). An almost final version of the laser, the socalled engineering prototype, is described in detail in [8]. The primary focus of this article is the stabilization and characterization of the PSL.…”

“…The third stage is an injection-locked ring oscillator [8] with an output power of about 220 W, called the high-power oscillator (HPO). Four Nd:YAG crystals are used as the active media.…”

“…The reference system features some minor modifications compared to the engineering prototype [8] concerning the optics: The external halo aperture was integrated into the laser system permanently improving the beam quality. Additionally, a few minor design flaws related to the mechanical structure and the optical layout were engineered out.…”

Progress and challenges in advanced ground-based gravitational-wave detectors

“…Laser-interferometric Gravitational Wave Detectors (GWDs) require high power laser sources which operate at a single frequency and in a pure spatial mode with extraordinary stability in their temporal and spatial performance. Such a laser system for the Advanced LIGO (aLIGO) GWD with an optical power of 200 W was developed and stabilized by a collaboration of the Laser Zentrum Hannover and the Albert-Einstein- Institute (AEI) in Hannover, Germany [6,7] with three of these lasers installed. The spatial purity of these lasers can be quantified by the fractional power in higher order spatial modes (HOM); before filtering, 3.1, 5.3, and 8.5 % was observed and after spatial filtering with a so-called pre-mode-cleaner (PMC) less than 0.5 % was seen for all three systems.…”

Injection locking of a low cost high power laser diode at 461 nm

“…The higher the injected power, the larger is the allowable frequency offset between the seed laser and the slave laser's resonance 8 . Close to quantum-limited intensity and phase noise can be achieved with this technique [9][10][11][12][13][14] . Recently, Y. Shimada et al…”