Abstract

We develop the cw extraction equations for single and multiple pass pumping and apply these equations to Tm:YAG when the lasing manifold is directly pumped. The lower manifold fractional concentration is f_a= (N_a/N₁) = exp(–E_a/kT)/ Z_a and contains the lower lasing level (a). The upper lasing level (b) is in the N₂ manifold with a fractional occupation f_b = (N_b/N₂) = exp(–E_b/kT)/Z_b. The effective decay time is τ. Furthermore, the absorption cross section is σ_a(λ_p) and the lasing cross section at λ_lis σ_e(λ_l). We begin with Fabry-Perot cavity with a single pass pump with transmissive optics at λ_p. At the lasing wavelength one mirror is perfectly reflecting and the outcoupler has an intensity reflectivity r and the laser field is described by forward and reverse fields.

© 1994 IEEE