LIGO Document G1701230-x0

Development of a squeezed light source at 2 micron

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G - Presentations (eg Graphics)
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The proposed LIGO Voyager upgrade consists of an interferometer operating at a wavelength in the 2 micron region. The design also features frequency-dependent squeezing for broadband quantum noise reduction.

We will present the first squeezed light results in the 2 micron region. Our experiment uses a frequency stabilised commercial thulium fibre laser operating at 1984 nm. This is frequency doubled to 992 nm which pumps the squeezer optical parametric oscillator (OPO). The squeezed vacuum is measured using balanced homodyne detection with a bright local oscillator. Thus far 0.5 dB have been measured in preliminary experiments.

The OPO consists of a doubly resonant bowtie cavity with a wedged PPKTP crystal as the nonlinear medium, and follows the design of previous ANU squeezers. The bowtie geometry provides isolation from backscattered light.

We will discuss the design considerations of the laser source, optical layout and OPO cavity parameters. We aim to ultimately produce 11dB of squeezing, and measure 5dB of squeezing, with this discrepancy dominated by the quantum defect of easily available photodiodes for the homodyne detector.

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Associated with Events:
Amaldi 12 held on 09 Jul 2017 in Hilton Hotel, Pasadena, CA

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