Measurement by light waves

Direct measurement of light waves.

The electromagnetic field of visible light performs approximately 10(15) oscillations per second. Although many instruments are sensitive to the amplitude and frequency (or wavelength) of these oscillations, they cannot access the light field itself. We directly observed how the field built up and disappeared in a short, few-cycle pulse of visible laser light by probing the variation of the fie...

Bending of Light by Gravity Waves

We describe the statistical properties of light rays propagating though a random sea of gravity waves and compare with the case for scalar metric perturbations from density inhomogeneities. For scalar fluctuations the deflection angle grows as the square-root of the path length D in the manner of a random walk, and the rms displacement of a ray from the unperturbed trajectory grows as D. For gr...

Precision Speed Measurement by Light

Driving Assistance Systems combine a variety of sensors with vehicle display, control and handling capabilities to improve driver performance and safety. As part of a project to evaluate new driving assistance systems using environmental sensors, engineers at Renault needed to measure the exact car speed in real time with better than 0.1 km/h accuracy. Common existing solutions are based on eit...

If light waves are stretched by gravitational waves, how can we use light as a ruler to detect gravitational waves?

Non-ionizing electromagnetic waves measurement and monitoring Systems

In this paper, portable and online monitoring systems for non-ionizing EMF measurement, as well as some measurement results in Tehran are discussed. First of all, standards and recommendations related to EMF monitoring, measurement and exposure such as ISIRI No.8567, ICNIRP guideline and ITU-K.83 are reviewed. Then, technical facts and operation of portable device and monitoring station are int...