Research Fellows Directory
Professor Anne Tropper MA D.Phil.
University of Southampton
Contemporary science and technology is concerned not only with small structures, but also with short time intervals, invoked to probe fleeting physical and chemical phenomena, or to increase the rate at which data can be transmitted and processed. State-of-art electronics can sample a signal waveform no faster than once every 30 picoseconds. To make faster measurements requires light; exploiting the technology of mode-locked lasers that emit regular optical pulses, each lasting for a few hundreds or tens of femtoseconds. Nobel Prize winning achievements in ultrafast science include the demonstration of a technique for counting optical frequencies, of immense importance in metrology. Yet despite their growing commercial importance, femtosecond lasers remain bulky, power-hungry devices. We lack a truly compact femtosecond technology with a low carbon footprint, such as might be used for optical clock distribution on a computer chip.
The lasers developed in my group have unique characteristics that may form a basis for such a technology. Unlike ultrashort-pulse diode lasers, they emit pulses of very high quality and large pulse energy, in perfect circular beams suitable for coupling into light-guiding structures such as optical fibres, or even semiconductor nanowires. Unlike conventional solid-state femtosecond systems, they can operate at high repetition rates, emitting tens or hundreds of billions of pulses per second, compatible with the requirements of high speed electronics. Physically they are fascinating because they shape pulses on the timescale of quantum mechanical carrier dynamics in the semiconductor. This project is working to realise miniature, low power femtosecond lasers that fulfil the demands of practical applications such as optical sampling or terahertz spectroscopy.
Interests and expertise (Subject groups)