Transient radiation-induced absorption at 1061 nm in LiNbO3 and MgO:LiNbO3

The transient radiation-induced 1061 nm absorption in pure and MgO doped lithium niobate has been measured using Sandia National Laboratories´ SPR III pulsed nuclear reactor. The samples are subjected to neutron fluences up to 10¹³/cm² (1 MeV Si) and total doses up to 7.5 krad. By using various shields, it has been found that gamma rays are the major contributors to the induced absorption at this wavelength. A plot of the natural logarithm of the transmittance versus time is given along with the peak induced absorption coefficient versus dose. The data indicate color centers with different time dependencies. A log-log plot of the transmission loss in dB/cm versus time indicates a 1/t^¼ time dependence initially