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Based on active optics, the zoom system design can no longer be confined to traditional methods of changing the distances between optical components for variable focal lengths. An all-reflective active zoom system with three mirrors is designed. The primary and third aspheric mirrors act as deformable mirrors to realize the transition among the different focal lengths by the curvature radius variation, while the second aspheric mirror is static. According to the third-order aberration theory and dimension calculations of the optical system requirements with the constraint limitations, the system's initial construction parameters can be achieved. This all-reflective active zoom system can realize zoom ratio is 3, focal length between 5 and 15 mm, field-of-view of 10–27.8°, and wide working wavelength from the visible to infrared.

The combination system of a pupil filter and an imaging system can achieve super-resolution. Aiming at exploring a method for designing and simulating such a super-resolving system, this paper introduced and discussed the pupil filter design theory at first. Then, based on the knowledge, a new continuous pupil filter and a corresponding imaging system were designed. The designed super-resolving factor G and Strehl ratio S were 0.7895 and 0.40, respectively. Finally, ZEMAX software was used to simulate the whole super-resolving system. The simulation results that G equaled to 0.7826 and S equaled to 0.3768, were reasonably smaller than the designed values. The results proved the validity and accuracy of this design and simulation procedure. With this method, it is possible to do risk assessment before production and reduce cost.

In order to study the laser plasma instabilities (LPIs) in the context of some novel six-side laser-driven indirect designs like the six-cylinder-port hohlraum and the three-axis cylindrical hohlraum, where the laser beams inject in hohlraum with a large angle. LPI experiments in cylindrical hohlraum with only outer beams were designed and performed based on the current laser arrangement condition of SGIII laser facility for the first time. Stimulated Brillouin backscatter (SBS) was found to be the dominant instability with high instantaneous reflectivity in experiments. A typical feature was obtained in the time-resolved spectra of SBS, which maintained similar for different laser intensities of the interaction beam. The experimental data are analyzed by the hydrodynamic simulations combined with HLIP code, which is based on the ray-tracing model. By analysis of experimental data, it is argued that the mixture of gas and Au in the region of their interface is important to SBS, which indicates the need for the mixture model between the filled gas and the high Z plasma from hohlraum wall in the hydrodynamic simulations. Nonlinear saturation of SBS as well as the smoothed beam are also discussed here. Our effective considerations of the ions pervasion effect and the smoothed beam provide utilitarian ways for improvement of the current ray-tracing method.

This paper uses the third-order aberration theory to design a reflective zoom optical system. The advantage of this method is that, by solving a set of Seidel aberration coefficient functions, it allows the designer to achieve the initial construction parameters of the optical system, i.e., radii of curvature and separations between mirrors, etc. In order to verify the accuracy of this method, a prototype of a coaxial zoom optical system with three mirrors is designed. This paper introduces the manufacturing process of the prototype in detail, describes the procedures of aligning and experimenting, and analyzes the experiment results in the end. In this way, the feasibility of this method is confirmed.

Optical diagnostic system plays an important role in inertial confinement fusion (ICF) experiment. Some key physical quantities and parameters in fusion can be diagnosed intuitively. In this review, three typical diagnostic systems on Shengang III facility are introduced, including imaging velocity interferometer system for any reflector (VISAR), fusion-reaction diagnostic system and backscatter light diagnostic system. VISAR can be used to measure velocity of free surface or shock wave traveling history in transparent media, which is an important diagnostic technique for shock wave velocity regulation, material compression characteristics and radiation temperature measurement. The fusion reaction-history diagnostic system can be used to accurately measure the fusion rate of ICF experiment. It’s a key diagnostic technique to study implosion dynamics and understand the mixed effect. Backscatter light diagnostic system is capable to measuring the energetic quotient stimulated by laser and plasma interaction (LPI), which produce important supports for calculating the coupling efficiency of driven laser and target.

In laser driven hohlraums, laser beams on the same incident cone may have different beam and plasma conditions, causing beam-to-beam backscatter difference and subsequent azimuthal variations in the x-ray drive on the capsule. To elucidate the large variation of backscatter proportion from beam to beam in some gas-filled hohlraum shots on Shenguang-III, two 28.5° beams have been measured with the Stimulated Raman Scattering (SRS) time-resolved spectra. A bifurcated fiber is used to sample two beams and then coupled to a spectrometer and streak camera combination to reduce the cost. The SRS spectra, characterized by a broad wavelength, were further corrected considering the temporal distortion and intensity modulation caused by components along the light path. This measurement will improve the understanding of the beam propagation inside the hohlraum and related laser plasma instabilities.