Complete characterization of weak, ultrashort near-UV pulses by spectral interferometry

We present a method for a complete characterization of a femtosecond ultraviolet pulse when a fundamental near-infrared beam is also available. Our approach relies on generation of second harmonic from the pre-characterized fundamental, which serves as a reference against which an unknown pulse is measured using spectral interference (SI). The characterization apparatus is a modified second harmonic frequency resolved optical gating setup which additionally allows for taking SI spectrum. The presented method is linear in the unknown field, simple and sensitive. We checked its accuracy using test pulses generated in a thick nonlinear crystal, demonstrating the ability to measure the phase in a broad spectral range, down to 0.1% peak spectral intensity as well as retrieving pi leaps in the spectral phase

Experimental study of the nature of the and excited states in using the reaction in inverse kinematics

10 pags., 8 figs., 4 tabs.The nature of the and excited states in is studied using the transfer reaction in inverse kinematics at 10A MeV at TRIUMF ISAC-II, in particular to assess whether either of them can be considered as an excited halo state. The angular distributions for both states are extracted using deuteron- coincidences and analyzed using a transfer model taking into account one-step and two-step processes. A good fit of the angular distributions is obtained considering only the one-step process, whereby an inner neutron of is removed, leaving the halo neutron intact. Higher-order processes however cannot be rejected. The small spectroscopic factors extracted suggest that the structure of both states is not uniquely halo-like, but rather display a more complex configuration mixing cluster and halo structures. Further insights are limited, as this experiment specifically probed the halo-like (but not cluster-like) configuration in both states.This work was partially supported by the U.S. Department of Energy (DOE) through Grants/Contracts No. DE-FG03-93ER40789 (Colorado School of Mines), No. DEFG02-96ER40978 (Louisiana State), No. DE-SC0021422 (Michigan State), No. DE-AC05-00OR22725 (Oak Ridge National Laboratory), the National Nuclear Security Administration (NNSA) under the Stewardship Science Academic Alliances program through U.S. DOE Cooperative Agreements No. DE-FG52-08NA28552, and the National Science Foundation under Grant No. PHY-1811815 (Michigan State). This work is also supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canadian Foundation for Innovation (CFI), the British Columbia Knowledge and Development Fund (BCKDF), the Italian National Institute for Nuclear Physics (INFN), the Spanish Ministry of Science and Innovation and FEDER funds under Projects RTI2018-098117-B-C21 and PGC2018-096994-BC21, and the Spanish Agency of Research (AEI) via Project No. PID2019-104714GB-C21.Peer reviewe