R. G. Beausoleil

High resolution laser spectroscopy of atomic hydrogen

As the simplest of the stable atoms, hydrogen permits unique confrontations between theory and experiment. Precision spectroscopy of hydrogen can be a powerful tool to determine better values of fundamental constants and to probe the limits of basic physics laws. Interest in high resolution laser spectroscopy of atomic hydrogen has been growing during the past two years, as documented by this and several following papers. At least four accurate new measurements of the Rydberg constant have been completed in 1986 [1–4]. Dramatic further improvements in spectral resolution and measurement accuracy should be achievable in the future.

All-reflective interferometry for gravitational-wave detection

The circulating power within an interferometric gravitational-wave detector is limited by thermal lensing in transmissive optical elements [1]. All-reflective interferometers have been proposed to overcome this limitation [2,3]. In this paper we discuss the use of a low-efficiency diffraction grating as an input coupler for a high-finesse cavity. Residual thermal effects due to absorption in the high-reflection optical coatings are discussed.

Setting upper limits on the strength of periodic gravitational waves from PSR [Formula Presented] using the first science data from the GEO 600 and LIGO detectors

Data collected by the GEO600 and LIGO interferometric gravitational wave detectors during their first observational science run were searched for continuous gravitational waves from the pulsar J1939+2134 at twice its rotation frequency. Two independent analysis methods were used and are demonstrated in this paper: a frequency domain method and a time domain method. Both achieve consistent null results, placing new upper limits on the strength of the pulsars gravitational wave emission. A model emission mechanism is used to interpret the limits as a constraint on the pulsars equatorial ellipticity.

The Hydrogen Atom in a New Light

It is well known that lasers and coherent light techniques have revolutionized high resolution spectroscopy. Today we have at our disposal a powerful arsenal of techniques which can overcome the Doppler broadening of spectral lines, achieving ever higher spectral resolution.1 At Stanford, we have long been fascinated by the prospects of applying such tools to atomic hydrogen.2 As the simplest of the stable atoms, hydrogen permits unique confrontations between experiment and quantum electrodynamic theory. After briefly reviewing past spectroscopic studies of hydrogen, we will report on some recent experimental advances which have opened the door to dramatic future improvements in resolution, creating unprecedented opportunities for precision measurements of fundamental constants and for stringent tests of basic physics laws.

CW Two-Photon Spectroscopy of Hydrogen 1s-2s and New Precision Measurements of Fundamental Constants

The 1s–2s transition of atomic hydrogen has an extremely narrow natural width which can give a resolution of 5 parts in 1016. In this paper we report on the first experiment using continuous wave ultraviolet radiation at 243 nm to excite this transition by Doppler-free two-photon spectroscopy. The resolution of 5 parts in 109 is an order of magnitude better than achieved in any previous measurements, and the continuous wave (cw) excitation opens the way for large improvements in the future: In all experiments until now, the resolution has been limited by the bandwidth of the pulsed lasers which were used to generate the intense tunable ultraviolet (uv) radiation.