Interference of two waves
Posted by mechlook info on February 2nd, 2012 05:51 PM | No Comment
Let us consider the effect of combining two monochromatic rays of light of different intensities having the amplitudes A1 and A2.
If it were possible to combine them in such "a way that the crest of one coincided with the crest ...
Introduction to Measurement by Light Wave Interference
Posted by mechlook info on January 11th, 2012 07:17 PM | No Comment
For understanding the phenomenon associated with interfero- metry, let us first study the nature of light. According to Huygens Theory, light is considered as wave motion propagated in the ether. The light, therefore, can be considered as an electro-magnetic wave ...
Moire scales and Moire Fringes
Posted by mechlook info on December 5th, 2011 12:51 AM | No Comment
In linear as well as rotary measurements, the grating (scales with a continuously repeating pattern of lines or grooves) play an important role. The gratings may have line spacings from 4 to 200 per mm, in lengths upto 4 ...
Scales and Gratings
Posted by mechlook info on December 5th, 2011 12:51 AM | No Comment
Scales are usually made of steel with lines (rulings) marked on them and spaced relatively far apart, so that some sort of interpolating device like vernier device is required to make accurate settings. In the case of gratings, the rules ...
Laser Interferometers
Posted by mechlook info on November 28th, 2011 10:55 PM | No Comment
This article is based on a similar article appearing in magazine "Machine Design” Vol. 47 No. 4. The measuring capacity in interferometers with lamp as source of light is limited because it is not possible to maintain the sharpness of ...
Optical Flats
Posted by mechlook info on October 26th, 2011 10:40 PM | No Comment
Optical flats are cylindrical in form with the working surfaces flat and are of two types :
Type A—It has only one surface flat. The working surface of this type of flat is indicated by an arrow head on the cylindrical ...
Interferometers
Posted by mechlook info on October 24th, 2011 12:09 AM | No Comment
Interferometers are optical instruments used for measuring flatness and determining the length of slip gauges by direct reference to the wavelength of light. The interferometer incorporates the extension of the application of the optical flat. It overcomes some of the ...