Q-switched partially coherent lasers with controllable spatial coherence

2021 ◽  
Vol 51 (2) ◽  
Author(s):  
Yushuang Wang ◽  
Xuanxuan Ji ◽  
Ziyang Chen ◽  
Jixiong Pu
Keyword(s):  
Laser Pulse ◽  
Spatial Coherence ◽  
Transverse Mode ◽  
Spatial Filter ◽  
Laser Resonator ◽  
Coherent Light ◽  
Partially Coherent ◽  
Partially Coherent Light ◽  
Degree Of Coherence ◽  
Output Laser

We develop a Q-switched degenerate laser, delivering a partially coherent light pulse of duration about 16 ns. The spatial coherence of the output laser pulse can be varied by tuning the spatial filter inside the laser resonator, and the oscillating transverse mode structure can be determined by measuring the degree of coherence of the output laser pulse. It is shown that the larger is the diameter of the spatial filter, the more are the oscillating transverse modes, and the lower is the degree of coherence. Based on coherent-mode representation for the partially coherent source, we can estimate the transverse mode contribution to the output partially coherent laser. The experimental results on suppressing speckle demonstrate that the generated partially coherent light possesses the characteristics of rapid reduction of spatial coherence, making it an ideal source for high-speed imaging and ranging applications.

scholarly journals The effect of spatial coherence of sources on synthetic aperture mapping

1991 ◽  
Vol 131 ◽  
pp. 10-14
Author(s):  
Daniel F.V. James
Keyword(s):  
Fourier Transform ◽  
Inverse Fourier Transform ◽  
Spatial Coherence ◽  
Full Description ◽  
Coherent Light ◽  
Partially Coherent ◽  
Interference Fringes ◽  
Partially Coherent Light ◽  
The Fourier Transform ◽  
Coherence Area

The interferometric mapping of astronomical objects relies on the van-Cittert Zernike theorem, one of the major results of the theory of partially coherent light [see, Bom and Wolf (1980), chapter 10]. This theorem states that the degree of spatial coherence of the field from a distant spatially incoherent source is proportional to the Fourier transform of the intensity distribution across the source. Measurement of the degree of spatial coherence, by, for example, measuring the visibility of interference fringes, allows the object to be mapped by making an inverse Fourier transform. (For a full description of this technique see Thompson, Moran and Swenson, 1986.)In this paper I present a summary of the results an investigation into what happens when the distant source is not spatially coherent (James, 1990). Using a heuristic model of a spherically symmetric partially coherent source, an analytic expression for the error in the measurement of the effective radius, expressed as a function of coherence area, can be obtained.

Interferometry of the intensity fluctuations in light. II. An experimental test of the theory for partially coherent light

1958 ◽  
Vol 243 (1234) ◽  
pp. 291-319 ◽  
Keyword(s):  
Theoretical Analysis ◽  
Laboratory Test ◽  
Systematic Error ◽  
Experimental Test ◽  
Coherent Light ◽  
Partially Coherent ◽  
Partially Coherent Light ◽  
Degree Of Coherence ◽  
Coincidence Counter ◽  
Intensity Fluctuations

A theoretical analysis is given of the correlation to be expected between the fluctuations in the outputs of two photoelectric detectors when these detectors are illuminated with partially coherent light. It is shown how this correlation depends upon the parameters of the equipment and upon the geometry of the experiment. The correlation may be detected either by linear multiplication of the fluctuations in the two outputs or by a coincidence counter which counts the simultaneous arrival of photons at the detectors. The theory is given for both these techniques and it is shown that they are closely equivalent. A laboratory test is described in which two photomultipliers were illuminated with partially coherent light and the correlation between the fluctuations in their outputs measured as a function of the degree of coherence. The results of this experiment are compared with the theory and it is shown that they agree within the limits of accuracy of the test; it is concluded that if there is any systematic error in the theory it is unlikely to exceed a few parts per cent.

scholarly journals Mie scattering of partially coherent light: controlling absorption with spatial coherence

2018 ◽  
Vol 26 (3) ◽  
pp. 2928 ◽  
Author(s):  
J. Alejandro Gonzaga-Galeana ◽  
Jorge R. Zurita-Sánchez
Keyword(s):  
Spatial Coherence ◽  
Mie Scattering ◽  
Coherent Light ◽  
Partially Coherent ◽  
Partially Coherent Light

Lecture demonstrations on the interference of partially coherent light

1979 ◽  
Vol 129 (9) ◽  
pp. 151
Author(s):  
G.S. Egorov ◽  
S.N. Mensov ◽  
Nikolai S. Stepanov
Keyword(s):  
Coherent Light ◽  
Partially Coherent ◽  
Partially Coherent Light
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