The Results of Lasing Linewidth Narrowing on VEPP-3 Storage Ring Optical Klystron

Lasing in the visible and ultraviolet ranges was reached in the optical klystron installed on a VEPP-3 storage ring in 1988 ⦋6⦌ with minimum relative linewidth”λ/λ = 1O^-4. In order to decrease the linewidth we have performed the experiments reported here. The optical cavity on VEPP-3 storage ring optical klystron was updated to install intracavity selective elements. We used the simplest selective element a glass plate with parallel planes as a natural interferometer. With a 1.2 mm thick glass plate installed inside the optical cavity we have reached lasing with a vary narrow linewidth. The minimum relative lasing linewidth, 2.7 · 10^-6 (λ = 6250 [formula omitted],”λ = 0.017 [formula omitted]), was 30 times narrower than the minimum one without the plate (”λ = 0.6 [formula omitted]). The average power was the same in both cases. Experiments on lasing linewidth narrowing with the use of the plates with different thickness are underway.