Light, radio-waves and X-rays are all just different parts of the spectrum of electromagnetic radiation. Our perception of their differing nature arises because the energy of the energy carrier, the photon, varies by many orders of magnitude between these different types of radiation, and also because the wavelengths of these types of radiation are so different. This makes the light behave differently in space and interact with matter in strongly variable ways. Our eyes can respond to different frequencies of visible light by revealing them as different colours. However, because the frequency of visible light is so high (e.g. green light corresponds to 564 trillion cycles per second) it has been impossible, until very recently, to measure the exact frequency of an optical signal i.e. to follow the time varying phase of a light beam. In just a few tens of places around the world it has now become possible to perform this task with relative ease. In our laboratory we can synthesise and measure the frequency of radiation at any chosen place in the visible spectrum. We do this using a highly innovative technique ("the frequency comb") that avoids many of the pitfalls of traditional methods: the importance of this approach is recognised in the awarding of the 2005 Nobel Prize in Physics to Ted Hänsch and Jan Hall. These high quality light signals can be used in high accuracy spectroscopy and thereby used to test certain aspects of Quantum Mechanics. It is necessary to develop many other technologies to support this work, and you can read more about our development of the optical synthesiser, our two optical atomic clocks, and our frequency stabilised lasers by following the link from the title. | | This division is directed towards creating extremely high frequency stable and low noise microwave oscillators. Topics include: 1. Testing fundamental physics with precision measurement 2. Precision frequency synthesis 3. Low noise frequency and phase techniques 4. Measurement of electonic and magnetic properties of materials 5. Novel high-Q microwave and millimetre wave resonators This pursuit is being undertaken at temperatures ranging from room temperature (300 K) to liquid helium temperature (4.2 K). Applications extend from commercial to fundamental metrology and physics. We are Physicists, so our main endeavour is to undertake exciting physics experiments. However, we are also aware of "spin-off" applications. Much of our work has been patented and commercialised and the development of this technology has helped us to build new tools that can in turn be used for fundamental physics applications. Our group undertakes projects that are suitable for the Engineering Technologist to the most fundamentally inclined Physicist. | |
