We report on measurements of the frequency noise of a highly stabilised injection locked Nd:YAG laser. We use a nested loop frequency stabilisation scheme to achieve a loop gain of ∼1×10
6 at Fourier ...frequencies around 1 kHz with frequency actuation applied only to the master oscillator. A frequency noise level of ∼
2×10
−5
Hz
Hz
−1/2
was measured for the master laser around this frequency using an independent, narrow line width, suspended analyser cavity. Furthermore we demonstrate that the frequency noise performance of the injection locked slave laser is identical to that of the master oscillator to this level. This performance is very close to the frequency noise specification for gravitational wave detection by GEO 600.
We show that the radiation pressure from an amplitude modulated, low power, Nd:YAG laser can be used to calibrate the displacement sensitivity of the Glasgow 10 m prototype gravitational wave ...detector. This demonstrates the possibility of radiation pressure being used as a standard method of calibrating long base line gravitational wave detectors. Further, this technique has the very important additional advantage that the test mass acted upon by the radiation pressure is not altered in any way, by, for example, the attachment of magnets, etc. The high
Q-factor of the internal modes, required for good detector sensitivity, is therefore preserved.
A measurement of the frequency noise at the relaxation oscillation frequency of a Nd:YAG monolithic non-planar ring laser is presented. By careful monitoring of various applied calibration signals, a ...limit to the frequency noise level of ∼ 6.3 × 10
−2
Hz/√Hz is set over the relaxation oscillation bandwidth and it is shown that this is approximately at the level to be expected, based on the relaxation oscillation induced time varying refractive index.
We present measurements of the displacement sensitivity from the Glasgow 10 m laser interferometric gravitational wave detector using an injection-locked Nd:YAG laser source; the type of laser system ...intended for use in some of the long-baseline observatories. The spectral density of displacement noise recorded above a few hundred Hz is
∼4×10
−19
m/
Hz
which is close to the limit imposed by the shot noise for the optical properties of the system. This represents the best displacement sensitivity obtained with an injection locked Nd:YAG laser to date and provides evidence that close to shot noise limited performance can be obtained with such laser systems.
We report on measurements performed with the Glasgow prototype gravitational wave detector which has recently been converted to operate with a Nd:YAG laser at 1064
nm. The differential displacement ...amplitude spectral density above a few hundred Hz is
∼5×10
−19
m/
Hz
which is consistent with the limitations imposed by shot noise in this frequency range. We also present sensitivity spectra over a lower frequency regime to highlight the impact of improved suspension designs.
Light from a monolithic Nd:YAG non-planar ring oscillator laser was phase modulated using a low-phase-noise 12 MHz crystal oscillator driving a LiNbO3 electro-optic modulator. An upper limit to the ...additional amplitude spectral density of the phase noise arising from the modulation process was measured to be 4 x 10 exp -8 rad/sq rt Hz over an 800-Hz bandwidth around the modulation frequency. This noise is in addition to the intrinsic phase noise of the oscillator. This is significantly less than that required by the GEO 600 gravitational wave detector. (Author)
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