An improved model-based wavefront sensorless adaptive optics algorithm is proposed for laser beam cleanup. Deformable mirror (DM) eigenmodes are used to replace traditional Lukosz modes in order to avoid DM fitting ...An improved model-based wavefront sensorless adaptive optics algorithm is proposed for laser beam cleanup. Deformable mirror (DM) eigenmodes are used to replace traditional Lukosz modes in order to avoid DM fitting errors. The traditional method is based on a sophisticated calibration process and solving linear equations. In our method, coefficients of DM eigenmodes are estimated by adding bidirectional modal biases into the system and then solving parabolic equations. The calibration process is omitted in our method, which makes it more feasible. From simulation and experimental results, the corrective accuracy of the improved method is higher than the traditional one.展开更多
To increase the quantum efficiency (QE) of a copper photocathode and reduce the thermal emit- tance of an electron beam, a drive laser with oblique incidence was adopted in a BNL type photocathode rf gun. The disadv...To increase the quantum efficiency (QE) of a copper photocathode and reduce the thermal emit- tance of an electron beam, a drive laser with oblique incidence was adopted in a BNL type photocathode rf gun. The disadvantageous effects on the beam quality caused by oblique incidence were analyzed qualitatively. A simple way to solve the problems through wavefront shaping was introduced and the beam quality was improved.展开更多
基金supported by the National Natural Science Foundation of China(No.61505008)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20131101120023)
文摘An improved model-based wavefront sensorless adaptive optics algorithm is proposed for laser beam cleanup. Deformable mirror (DM) eigenmodes are used to replace traditional Lukosz modes in order to avoid DM fitting errors. The traditional method is based on a sophisticated calibration process and solving linear equations. In our method, coefficients of DM eigenmodes are estimated by adding bidirectional modal biases into the system and then solving parabolic equations. The calibration process is omitted in our method, which makes it more feasible. From simulation and experimental results, the corrective accuracy of the improved method is higher than the traditional one.
基金Supported by Science Foundation of Ministry of Education of China ('985 project':173123200402002)
文摘To increase the quantum efficiency (QE) of a copper photocathode and reduce the thermal emit- tance of an electron beam, a drive laser with oblique incidence was adopted in a BNL type photocathode rf gun. The disadvantageous effects on the beam quality caused by oblique incidence were analyzed qualitatively. A simple way to solve the problems through wavefront shaping was introduced and the beam quality was improved.