Reported is cw lasing and sub-100 femtosecond pulse generation in end-
pumped Cr3+:LiSr0.8Ca0.2AlF6, a congruently melting compound intermedi
ate between Cr3+:LiSrAlF6 and Cr3+:LiCaAlF6. Using a dispersion compen
sated cavity with no active or passive mode-locking elements in the ca
vity, self-sustained stable modelocked pulses of 90 fs duration at 140
MHz repetition frequency were initiated by rocking of the output coup
ler.