¶ Pre-Stabilized Laser
The pre-stabilized laser (PSL) provides frequency and intensity stabilized light for the Advanced LIGO interferometers at the specifications required for entrance to the Input Optics (IO) chain. The heart of the PSL is a three-stage laser system.
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Stage one consists of a 2W non-planar ring-oscillator (NPRO) that uses a Nd:YAG crystal as the laser medium and resonator. The NPRO is pumped by laser diodes at 808 nm and produces a 1064nm beam. The PSL is able to meet LIGO's frequency stability requirement for the laser light in part through the performance of the NPRO's monolithic resonator.
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The second stage delivers an output power of 35 W. Here the NPRO beam passes through four Nd:YVO4 crystals, also pumped at 808 nm.
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The third stage, the high-power oscillator, contains an injection-locked ring oscillator that delivers roughly 220 W. Four Nd:YAG crystals are pumped at 808 nm, with the pump light traveling to the PSL table through optical fibers from a room dozens of meters away. A feedback loop locks stage three to stage two. Light produced in the latter two stages retains the extraordinary stability imparted by the NPRO at stage one.
figure: Reference cavity output
Here's a side view taken during the PSL upgrade in June 2021LHO:59228
¶ Channel Name Breakdown:
| Name | Description |
|---|---|
| Channels | |
| PSL | Pre-Stabilized Laser |