A tunable, solid, Fabry-Perot etalon for solar seismologyA solid etalon has been designed and fabricated from a 50-mm diameter wafer of optical-quality lithium niobate. The finished etalon has a free spectral range of 0.325 nm at 588 nm. The parallel faces are coated with silver, and the central 15-mm aperture of the etalon has a finesse of 18.6. The reflective faces double as electrodes, and application of voltage will shift the passband. This feature was used in a servo circuit to stabilize the passband against temperature and tilt-induced drifts to better than three parts in one billion. Operated in the stabilized mode for day-long sessions, this filter alternately samples the wings of a narrow atomic absorption line in the solar spectrum and produces a signal proportional to velocity on the solar disk. The Fourier transform of this signal yields information on acoustic waves in the solar interior.
Document ID
19870049106
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Rust, David M. (Johns Hopkins University Laurel, MD, United States)
Burton, Clive H. (Johns Hopkins Univ. Laurel, MD, United States)
Leistner, Achim J. (CSIRO Div. of Applied Physics, Sydney, Australia)