OSA Student Chapter Meeting
SPEAKER: John Mason
TITLE: Principles of the integrating cavity absorption meter
The absorption spectrum of molecules and atoms provides important information about the energy structure and behavior of atoms and molecules. While a number of spectroscopy techniques exist, few are capable of providing accurate values for samples with severe scattering. Over the past 10 years, improvements in integrating cavity technology have lead to the creation of several scattering-independent spectroscopy techniques. We will discuss the basic principles of the integrating cavity absorption meter (ICAM) and how this technique is used to study the absorption coefficients of water. Data for the spectral light absorption of pure water from 250 to 550 nm have been obtained using an integrating cavity made from a newly developed diffuse reflector with a very high UV reflectivity. The data provide the first scattering-independent measurements of absorption coefficients in the spectral gap between well-established literature values for the absorption coefficients in the visible (> 400 nm) and UV (< 200 nm). A minimum in the absorption coefficient has been observed in the UV at 344 nm; the value is 0.000811+-0.000227 m-1.

SPEAKER: Joe Becker
TITLE: Strontium Optical Lattice Clock Comparison Over 1415 Kilometers
Researchers from the Time Space Reference Systems Lab (SYRTE) in Paris, France and the National Metrology Institute (PTB) in Braunschweig, Germany directly compared Strontium Optical Lattice Clocks. This direct measurement of clock frequency was preformed over 1400 km and marks the first long distance optical frequency comparison. Both groups used fiber optic lines carrying the signal using the telecommunication wavelengths (1550 nm). A fractional frequency of $3\times10^{-17}$ was measured increasing the accuracy of long distance frequency comparison by an order of magnitude. This work opens the door to a potential clock network which could prove to be a unique tool for geology, astronomy and physics.

Thursday,September 15, 2016
IQSE 578, 12:30 noon
Mitchell Physics Building

Department of Physics and Astronomy
Institute for Quantum Science and Engineering
Texas A&M University

(Pizza lunch as usual. Newcomers welcome!)

Host: Sasha Zhdanova