1. Circle method Wavefront with radius Circle with diameter R(z) R(z) z r
Waist plan
-> The waist plane is located inside the circle

2. (R2 radius of curvature)
Plano-concave cavity
Circle of diameter R2
Plan mirror Zr L
Waist plan
Curved mirror
(R2 radius of curvature)

3. Biconcave cavity (R1 radius of curvature) (R2 radius of curvature)
Circle of diameter R1
Circle of diameter R2 Zr
Waist plan
Curved mirror
(R1 radius of curvature)
Curved mirror
(R2 radius of curvature)

4. Symetric cavity Circle of diameter R1 Circle of diameter R2 Zr
Waist plan
Curved mirror
(R1 radius of curvature)
Curved mirror
(R2 radius of curvature)
Waist plan = symetry plan

5. High order transverse modes Hermite-gaussian modes

6. High order transverse modes Laguerre-gaussian modes

7. Example of beam profile with M2>1