Introduction: The history of using light as a working tool

Abstract

Certainly the earliest pioneers of optics realized that sunlight focused through a piece of curved glass can be used to perforate or slice thin pieces of wood or similar materials. Since then it has been known that light of a high power density can be used much like mechanical tools such as knives or scissors. At the beginning of this century, microscopists learned that a powerful conventional light source focused into a microscope could be used to manipulate biological objects. A conventional light source could be focused down to a spot size of a few micrometers. It was immediately clear that the “Strahlenstich”, as it was called, was a tool for biologists. Probably the first work using highly focused light to manipulate biological material was that of S. Tschachotin (1912). Fig. 1 is a facsimile of the first page of Tschachotin’s paper.