Earth Science: Optics – From Microscope to Optoelectronics
The first spectacles were made from polished semiprecious stones, as early as the late Middle Ages. Yet it was the invention of the microscope and the telescope that laid the foundation for precision optics.
Telescopes and microscopes both take advantage of the fact that light can be deviated from its linear propagation path when it is passed through suitably polished glass lenses. For instance, a condensing lens concentrates parallel light rays into a point: the focal point. Two such lenses—placed in line at the proper distance apart-form an object enlarged on the retina of an observer.
When used on a telescope and in a microscope these are called objective and ocular (in Latin oculus: “eye”) lenses. Nowadays optical equipment fulfills diverse tasks in measuring technology, biological and medical research, and in astronomy. From radio telescopes and UV detectors to x-ray microscopes, all parts of the visible and invisible spectrum are being utilized and studied.
Microscopes have even been developed for observing the particle radiation from electrons and neutrons.
Calculating with light
Computers are sometimes referred to as electronic brains because information can be transmitted, manipulated, or stored in the form of electrons. However, electrical resistance limits current flow and creates undesirable waste heat, the smaller the circuits become. Therefore increasingly powerful cooling needs to be built into modern computers.
Moreover, electrons influence each other because of their electric charge, meaning there is a limit to how small we can make standard computer chips. A way out of this troublesome dilemma would be with photons: that is with light particles.
They take up the same space in almost unlimited numbers, all traveling at the speed of light. That is the reason why so much data can be sent simultaneously via fiber optics at such a high speed. It is hoped that significant advances can be achieved within the new field of pure optical circuit elements with so-called nonlinear crystals.
The way to an advanced computer made of light or “photonic brain” may possibly not be very far, running at speeds that will make modern super-computers look seriously outdated.
LASER
Normal light, such as that generated by the sun, is a mixture of many different waveforms with different directions, energies, and so on. Lasers, however, behave differently.
With a pulsing amplification process, a large number of identical waves are being generated, where every wave crest matches the adjacent wave crest, and every wave trough matches the next wave trough. An extremely bundled and straight beam is created.
In everyday life, we encounter lasers in CD and DVD players and supermarket checkouts, often as unseen but vital components.