arXiv subjects

D. J. Hosken

Publications and source records attributed to D. J. Hosken.

3 recordsLinked to original sources

arXiv2008

Observation of Three Mode Parametric Interactions in Long Optical Cavities

We report the first observation of three-mode opto-acoustic parametric interactions of the type predicted to cause parametric instabilities in an 80 m long, high optical power cavity that uses suspended sapphire mirrors. Resonant interaction occurs between two distinct optical modes and an acoustic mode of one mirror when the difference in frequency between the two optical cavity modes is close to the frequency of the acoustic mode. Experimental results validate the theory of parametric instability in high power optical cavities.

gr-qc↗

arXiv2006

Inter-species regression analysis

When conducting inter-species regression analyses, the phylogenetic relationships between the individual species need to be taken into account. In this paper, a procedure for conducting such analyses is proposed, which only requires the use of a measure of relationship between pairs of species, rather than a complete phylogeny, and which at the same time assesses the importance to be attached to the relationships with regard to the conclusions reached. The procedure is applied to previous data, relating testis size to mean hind tibia length, duct length and spermathecal area in 15 species of Scathophagidae.

q-bio.PE↗

arXiv2006

Compensation of Strong Thermal Lensing in High Optical Power Cavities

In an experiment to simulate the conditions in high optical power advanced gravitational wave detectors such as Advanced LIGO, we show that strong thermal lenses form in accordance with predictions and that they can be compensated using an intra-cavity compensation plate heated on its cylindrical surface. We show that high finesse ~1400 can be achieved in cavities with internal compensation plates, and that the cavity mode structure can be maintained by thermal compensation. It is also shown that the measurements allow a direct measurement of substrate optical absorption in the test mass and the compensation plate.

gr-qc↗