Page 40 - Tunable Lasers Handbook
P. 40
2 Narrow-tinewidth laser Oscillators 11
for a grating in Littrow configuration [13].
The generalized double-pass dispersion for any prismatic array composed of
r prisms (Fig. 6) is given by [ 1,2,34-361
where
and
the
are
Here, k,,J = cos ‘PI,, 1 cos and k2,j = cos @,,j,/cos y ~ ~ , ~individual beam
expansion coefficients corresponding to the incidence and exit face of the prism,
respectively. Also fil,m = tan $l,m/nm, %,m = tan $22,m/nm, and (an,IaA) is charac-
teristic of the prism material. To estimate the single-pass dispersion (do2,, IaA) of
the multiple-prism beam expander, the return-pass dispersion given in Eq. (1 1)
should be multiplied by (2 M,M,)-1 to obtain the expression [36]
For multiple-prism assemblies composed of right-angle prisms (as shown in
Fig. 2) designed for orthogonal beam exit, Eq. (1 1) reduces to [2]
Further, if the prisms in the preceding expander are manufactured of the same
material and deployed so that the angle of incidence is the Brewster’s angle, then
Eq. (14) reduces to
