Simple piezoelectric-actuated mirror with 180 kHz servo bandwidth

We present a high bandwidth piezoelectric-actuated mirror for length stabilization of an optical cavity. The actuator displays a transfer function with a flat amplitude response and greater than 135$^\circ$ phase margin up to 200 kHz, allowing a 180 kHz unity gain frequency to be achieved in a closed servo loop. To the best of our knowledge, this actuator has achieved the largest servo bandwidth for a piezoelectric transducer (PZT). The actuator should be very useful in a wide variety of applications requiring precision control of optical lengths, including laser frequency stabilization, optical interferometers, and optical communications

Learning from Noise

Learning from noisy data is very difficult. But if a certain method fails people often try again - instead trying to understand why they fail

Unexpectedly small intrashell L1–L3 vacancy transition rate in 62Sm

Stötzel R, Werner U, Sarkar M, Jitschin W. Unexpectedly small intrashell L1–L3 vacancy transition rate in 62Sm. Physical Review A. 1992;45(3):2093-2096

Unexpectedly small intrashell L1−L3\mathrm{L_1 - L_3} vacancy transition rate in 62Sm\mathrm{_{62}Sm}

The individual decay channels of samarium L-subshell vacancy states were experimentally investigated by the synchrotron photoionization method. For the Coster-Kronig yield f13, i.e., the relative contribution of the nonradiative L1−L3 channel to the total decay of L1-vacancy states, the value f13=0.19±0.03 was obtained. This is a surprisingly small value regarding both prediction from theory (e.g., f13=0.32 according to Chen, Craseman, and Mark [Phys. Rev. A 24, 177 (1981)]) and extrapolation from neighboring elements (f13≊0.32 for the elements with Z=72–74 according to our previous work [U. Werner and W. Jitschin, Phys. Rev. A 38, 4009 (1988)])