Design of Diffractive Optical Elements for Chromatic Aberration Correction in High-Energy Petawatt Laser System

With high diffractive efficiency, Continuous Relief Diffractive Optical Elements (CR-DOE) can be used to eliminate chromatic aberration, partial aberration and simplify optical system. The technology for CR-DOE with Laser Direct Writing method has advantages of simple process, short period and low cost. The paper studied on the characterization method of laser power for the technology. The principle of mask fabrication of CR-DOE by Laser Direct Writing is described in the paper. The relations between microstructure depth and laser power, exposing position radius and laser power were studied. The results showed that microstructure depth changes in direct ratio to laser power and laser power should change in direct to exposing position radius while several same depth microstructures were fabricated at different radius. At the end, the paper gave the charactering method and also fabricated the mask of a kind of centrosymmetric continuous relief diffractive focus lens with the method.

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High Concentration Photovoltaics (HCPV) with Diffractive Secondary Optical Elements

Photonics ◽

10.3390/photonics6020068 ◽

2019 ◽

Vol 6 (2) ◽

pp. 68 ◽

Cited By ~ 9

Author(s):

Furkan Sahin ◽

Musa Yılmaz

Keyword(s):

Low Cost ◽

Optical Design ◽

Chromatic Aberration ◽

High Energy ◽

Solar Concentrator ◽

High Concentration ◽

Acceptance Angle ◽

Optical Elements ◽

Optical Efficiency ◽

Single Material

Multi-junction solar cells can be economically viable for terrestrial applications when operated under concentrated illuminations. The optimal design of concentrator optics in high concentration photovoltaics (HCPV) systems is crucial for achieving high energy conversion. At a high geometric concentration, chromatic aberration of the primary lens can restrict the optical efficiency and acceptance angle. In order to correct chromatic aberration, multi-material, multi-element refractive elements, hybrid refractive/diffractive elements, or multi-element refractive and diffractive systems can be designed. In this paper, the effect of introducing a diffractive surface in the optical path is analyzed. An example two-stage refractive and diffractive optical system is shown to have an optical efficiency of up to 0.87, and an acceptance angle of up to ±0.55° with a 1600× geometric concentration ratio, which is a significant improvement compared to a single-stage concentrator system with a single material. This optical design can be mass-produced with conventional fabrication methods, thus providing a low-cost alternative to other approaches, and the design approach can be generalized to many other solar concentrator systems with different cell sizes and geometric concentration ratios.

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Adaptive Optical Systems in Air-Based Laser System. Analytical Review. Part 1. Current Status

Mechanical Engineering and Computer Science ◽

10.24108/0419.0001464 ◽

2019 ◽

pp. 1-23

Author(s):

Yu. I. Shanin

Keyword(s):

Laser Radiation ◽

Adaptive Optics ◽

Laser System ◽

The United States ◽

High Energy ◽

Optical Systems ◽

Current Status ◽

Powerful Laser ◽

Optical Elements ◽

Laser Systems

Aviation-based laser complex is a complex technical object. Among its systems, we analyse only an adaptive optical system and issues related to its performance, and show that the effectiveness of the complex without an adaptive system is small. The analysis was carried out in terms of systems that were developed in the United States.Using the tilt corrector, an adaptive optics provides accurate tracking of the object. A deformable mirror performs correction of higher-order radiation wavefront aberrations caused by atmospheric turbulence for incoming light and outgoing laser radiation. The advantages of onboard laser systems are the beam propagation at the speed of light and the low price of a shot. The disadvantages are that the target should be in line-of-sight and there is a negative influence of the atmosphere. Another negative influences are vibrations of the aircraft and the aero-optical problem because of output radiation. An assured thermal target kill is possible at the range of 3-10 km. A functional kill and suppression are capable at ranges of 102-103 times longer than for the thermal target kill.Among the programs for the development of an onboard laser in the USA, the YAL, ATL and ABL programs are considered. The YAL program is an attempt to intercept short-and medium-range missiles with a powerful laser. The ATL system was to be installed on a heavily armed ground support aircraft. An airborne laser (ABL) is a demonstration of the U.S. Air Force of a high-energy laser system designed to destroy missiles on their boost phase. Over 30 years and several tens of billions of dollars were expended to develop the systems. Unfortunately, all onboard laser development programs have been closed.Experience of the flying laboratories is realized by Cessna Citations and Falcon 10s planes and is relevant, as it gives the chance to estimate adverse effects of aero-optics and vibrations directly in flight.Among the problems that need to be solved when creating adaptive optics for an onboard laser, the following are highlighted:- loss of compensation capabilities;- thermal effects of laser radiation on optical elements;- creation of attenuators and radiation couplers;- mitigating the negative effects of the onboard platform on radiation;- operation reliability of the actuators of correction devices;- technological working off of the uncooled optical elements which are affected by powerful laser radiation.For newly developed aviation-based laser systems, it is necessary to envision the niche in which their use will be most efficient.

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Design and Management of Stray Light for Compact Final Optics Assembly on the High Energy Laser System

International Journal of Optics ◽

10.1155/2021/6655866 ◽

2021 ◽

Vol 2021 ◽

pp. 1-7

Author(s):

Deyan Zhu ◽

Yang Chen ◽

Ping Li ◽

Bin Feng ◽

Yajun Pang

Keyword(s):

Laser System ◽

Light Trap ◽

High Energy ◽

Optical Field ◽

Stray Light ◽

Experimental Demonstration ◽

Optical Elements ◽

First Order ◽

Energy Laser ◽

High Energy Laser

In this study, a model is proposed to design and manage the stray light of a compact final optics assembly (FOA) for a high energy laser system. Based on the method we proposed, the high-order stray light can be managed to optimizing the position and angle of the optical elements. A light trap is designed to manage the first-order stray light with high fluence. Applying the method, we provide an experimental demonstration to designing a compact FOA. By comparing the cleaning results with no management testing result, it proves that using the above design and management, it can achieve the great improvement of cleanliness from ISO Class 5 to Class 3, which is significant to improve the output capability of the high energy laser system. In addition, we also verify the stray light by an optical field paper. It demonstrates that the field characteristics and position calculation of stray light are reliable.

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