1 shows the experimental set-up to determine coherence and wavelength. Active 8 years, 4 months ago.

Line width of green DPSS laser. The more modes there are in the output, the wider the line width of the laser; and the wider the line width, the shorter the coherence length. LEP 2.2.06 Coherence and width of spectral lines with Michelson interferometer Shifting the mirror S 2 by a distance D and observing the appa- rition of n dark zones, the wavelength is obtained from the fol- lowing equation: l = (light travels twice over path D) (3) Using the green Hg-line… Ask Question Asked 8 years, 8 months ago. 3. If the two fringe systems (S 1-A&B-screen and S 2-A&B-screen) overlap with their maxima and minima falling together, the resulting fringe pattern is highly visible at P. the radiation from two point sources at A and B are highly spatial-coherent. Thanks for contributing an answer to Physics Stack Exchange! Viewed 2k times 6 $\begingroup$ Could someone suggest what is the line width/mode stability/coherence length of generic cheapo green (532nm) DPSS laser? Temporal Coherence … 1. Verification of the coherence condition for non punctual light sources. Spatial Coherence width First, consider two point sources S 1 & S 2 separated by s, double slits A and B. 2.
coherence length is found to be (1) and for the corresponding coherence time one thus finds (2) If both the coherence length and the wavelength centre are known, the line width can be calculated according to (1) and the corresponding coherence time according to (2).

The values determined in 1. are used to calculate the coherence time and the full width at half maximum value of the spectral line. 2.

9-6. where Δ ν is the (full width at half-maximum) linewidth (optical bandwidth).This coherence length is the propagation length after which the magnitude of the coherence function has dropped to the value of 1 / e.. The coherence time is intimately linked with the linewidth of the radiation, i.e., the width of its spectrum. In the case of an exponential coherence decay as above, the optical spectrum has a Lorentzian shape, and the (full width at half-maximum) linewidth is Spatial Coherence is a measure of the correlation of a light wave’s phase at different points transverse to the direction of propagation - it tells us how uniform the phase of a wavefront is. line as well as of its coherence length.
The relationship between the growth of molecular aggregates, aggregation number, and their optical properties is an active area of research [10] . The values determined in 1. are used to calculate the coher-ence time and the half width value of the spectral line. to tolerate for the short coherence time of our violet diode laser due to the long line width for our pumping source, 3nm giving a coherence length of (5.46×10 -5 m) compared with (17) and (13) , where the coherence length equals to (3 m) and (1.632×10 -4 m) respectively. Verification of the coherence condition for non punctual light sources. If only one oscillation mode contributes to the output, the laser is single-frequency and has a very long coherence length: often on the order of ten meters or more. 3. Set-up and procedure Fig.

The spectral width (full-width at half-maximum, FWHM) of the absorption peak of the J-aggregate varies with the coherence length as N −1/2, where N is the spectroscopic aggregation number , . Determination of the wavelength of the green Hg spectral line as well as of its coherence length.