
GAUSSIAN BEAMS 297
−10
−5 0 5 10
−10
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10
(A) (B)
−1
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−10 −5 0 5 10
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(C)
−5 0 5 10
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(D)
−5 0 5 10
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1
Figure 9.9 Laser cavity design. Four cavities are shown. The first three correspond to the
cavities in Figure 9.8. A flat output coupler at z = 0, and a concave back mirror at z =−6
(A) produce a collimated beam. The opposite configuration (B) produces a diverging output
beam at z =+6. Two identical concave mirrors at z =±3 produce a waist in the center
(C). With the front mirror at z =−3 and the back mirror at z =−9 (D), the output beam is
converging.
radius of curvature to match ρ. We note