How many principles does it take to change a lightbulb ... into a laser? (Plus some research)

Speaker: Professor Howard Wiseman 
Affiliation: Griffith University

Abstract

The laser is central to much modern science and technology. But what fundamental features distinguish laser light from thermal (e.g. light-bulb) light? Here I suggest four: directionality, monochromaticity, brightness, and stable intensity. The first three principles suffice to show, quantitatively, that a laser must be constructed very differently from a light bulb. This quantitative comparison has led to a new research direction in my group: how does the number of coherent excitations inside the laser limit the coherence of its beam? In answering this, we have overturned the orthodoxy of six decades by reimagining how a laser could work.