SAM – saturable absorber mirror
SAM – saturable absorber mirror
SAM – saturable absorber mirror
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R<strong>SAM</strong> at λ = 1064 nm with front <strong>mirror</strong> reflection r f = 0.97,unsaturated absorption of A = 1.5% and resonance order m = 4> Relaxation timeThe <strong>saturable</strong> <strong>absorber</strong> layer consists of asemiconductor material with a direct bandgap, which is slightly smaller than thephoton energy. During the absorptionelectron-hole pairs are created in the film.The relaxation time τ of the carriers is veryshort due to fast non-radiative relaxationchannels introduced by low-temperaturegrowth of the <strong>absorber</strong> layer.Recovery of the absorption A 0with a relaxation time τ = 10 psTypical values of the relaxation time τ arebetween 5 and 20 ps.The relaxation of the carriers and therecovery of the absorption A(t) after thesaturation can be described asA(t) = A 0 [1 - exp(-t/τ )]withA(t)A 0tτtime dependent absorptionsmall signal <strong>saturable</strong> absorptiontimerelaxation timeSeongKyeong Photonics 21 info@skphotonics.com