## Abstract

We demonstrate experimentally an optical imaging method that makes
use of a slit to collect tomographic projection data of arbitrarily shaped
light beams; a tomographic backprojection algorithm is then used to
reconstruct the intensity profiles of these beams. Two different
implementations of the method are presented. In one, a single slit is scanned
and rotated in front of the laser beam. In the other, the sides of a polygonal
slit, which is linearly displaced in a *x-y*
plane perpendicular to the beam, are used to collect
the data. This latter version is more suitable than the other for adaptation
at micrometer-size scale. A mathematical justification is given here for the
superior performance against laser-power fluctuations of the tomographic slit
technique compared with the better-known tomographic knife-edge
technique.

© 1997 Optical Society of America

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### Equations (7)

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(1)
$${F}_{\mathrm{\theta}}\left(t\right)={\int}_{\mathrm{uncovered}\mathrm{area}\left(\mathrm{\theta},t\right)}I\left(x,y\right)\mathrm{d}A,$$
(2)
$${P}_{\mathrm{\theta}}\left(t\right)=\frac{\mathrm{d}{F}_{\mathrm{\theta}}\left(t\right)}{\mathrm{d}t}.$$
(3)
$${N}_{\mathrm{ke}}\left(\mathrm{\theta},t\right)={N}_{L}{\overline{P}}_{\mathrm{\theta}}\left(t\right)\mathrm{\Delta}t/{\overline{F}}_{\mathrm{\theta}}\left(t\right).$$
(4)
$${N}_{\mathrm{ke}}\left(\mathrm{\theta},t\right)\ll {N}_{L}.$$
(5)
$${\mathrm{\sigma}}_{\mathrm{sl}}\left(\mathrm{\theta},t\right)={\mathrm{\sigma}}_{0}{\overline{P}}_{\mathrm{\theta}}\left(t\right)\mathrm{\Delta}w/\overline{\mathcal{P}},$$
(6)
$${N}_{\mathrm{sl}}\left(\mathrm{\theta},t\right)={\overline{P}}_{\mathrm{\theta}}\left(t\right)\mathrm{\Delta}w/{\mathrm{\sigma}}_{\mathrm{sl}}\left(\mathrm{\theta},t\right)={N}_{L}.$$
(7)
$${N}_{\mathrm{ke}}\left(\mathrm{\theta},t\right)\ll {N}_{\mathrm{sl}}\left(\mathrm{\theta},t\right).$$