Light, sight, and quanta

Understanding light quanta : The Photon

An antisymmetric tensor, the photon tensor, is defined for the description of the photon as a massless relativistic particle. The photon can be visualized as an essentially two dimensional rotating object. The quantum mechanical description of a single photon is presented and it is shown that it is wrong to associate the quantum states of a photon with the macroscopic electromagnetic fields. Th...

Light, sight, and quanta SönkeJohnsenThe Optics of Life — A Biologist's Guide to Light in Nature2012Princeton University PressPrinceton, NJISBN 978-0-691-13990-6

a decent science background. (Sönke himself says he was bored by physics in college and switched to maths, but clearly what was already there stuck [3]). The book is by no means all theory; there are a host of examples, many from his own studies, of the ways in which animals make use of the different kinds of interactions between light and matter. The book begins with the measurement of light a...

Non-Visual Photoreception: Sensing Light without Sight

Recent work in blind human subjects has confirmed the presence of a non-visual ocular photoreceptive mechanism similar to that described in blind mice. This system appears to subserve circadian photic entrainment, the pupillary light response, and a number of other aspects of neurophysiology and behavior.

The Path of Light Quanta in an Interference Field.

Energy, Quanta, and Vision

1. Direct measurements of the minimum energy required for threshold vision under optimal physiological conditions yield values between 2.1 and 5.7 x 10(-10) ergs at the cornea, which correspond to between 54 and 148 quanta of blue-green light. 2. These values are at the cornea. To yield physiologically significant data they must be corrected for corneal reflection, which is 4 per cent; for ocul...