Stephen J. Matthews

Contributing Editor

Stephen J. Matthews was a Contributing Editor for Laser Focus World.

FIGURE 1. This view of the northern ice cap of Mars is constructed using elevation data from an on-board laser altimeter together with photographs taken by the Mars Global Surveyor, now in orbit. The ice cap is about 1200 km wide with an average depth of 1 km.

Detectors & Imaging

The view from space

Stephen J. Matthews

Jan. 1, 2004

Advances in CCD technology have allowed satellite images to greatly improve in spatial and spectral resolution.

FIGURE 1. Profilometers based on CCD arrays can provide real-time displays of 3-D beam profiles.

Detectors & Imaging

Good fundamentals

Stephen J. Matthews

Oct. 1, 2002

Accurately determining laser beam diameter and divergence requires a clear understanding of the principles of measurement.

FIGURE 1. The small size and flexible design of holographic gratings enable modern compact spectrometers. Instruments such as these are used in applications as varied as the colorimetry of LEDs for illumination to the characterization of optical networks.

Optics

Numbering the waves

Stephen J. Matthews

Aug. 1, 2002

Familiar to the Chinese for centuries, the dispersion of sunlight by a prism was shown by Isaac Newton in the 17th Century to result from the wave nature of light.