Reflection of light by a convex Fresnel lens gives rise to two distinct images. A highly convex inverted real reflective image forms on the object side of the lens, while an upright virtual reflective image forms on the opposite side of the lens. I describe here a set of laser experiments performed upon a Fresnel lens. These experiments provide…

To help students develop an understanding of the proper use and function of spectrographs and monochromators we describe a student-assembled spectrograph using a "webcam" detector. The apparatus also works well as a low-cost demonstration, helping students make connections between an atomic spectrum observed by eye and a plot of the relative…

Applications of a simple approximation of Bessel functions of integer order, in terms of trigonometric functions, are discussed for several examples from electromagnetism and optics. The method may be applied in the intermediate regime, bridging the "small values regime" and the "asymptotic" one, and covering, in this way, an area of great…

Explains the asymmetry between left-right and up-down when your image is viewed in a plane mirror in psychological rather than physical terms. (GS)

Discusses developments in the field of gradient index optical lenses for resolving problems of lens spherical abberration. (SL)

Discusses the optics of fly fishing, considering where to cast the fly once a fish is seen. Also considers what the fisherman looks like to the fish, examining refraction at a water surface, actual and apparent light rays, and how sticks in the water might look to a fish. (JN)

The diffraction bands caused by a thin transparent plate of glass inserted over half the field in a spectrometer are discussed. (TS)

The laws of reflection, image formation, and geometric concepts are discussed in relationship to the images observed in a totally reflective sphere. (TS)