Energy Delivery Over Long Distances
Laser Beam Control by Means of Nonlinear and Coherent Optics Techniques
Tech Area / Field
- SAT-OTH/Other/Space, Aircraft and Surface Transportation
- PHY-OPL/Optics and Lasers/Physics
8 Project completed
Senior Project Manager
Malakhov Yu I
Research Institute for Laser Physics, Russia, St Petersburg
- National Aerospace Laboratory, Japan, Tokyo\nTohoku University, Japan, Sendai\nNational Aerospace Laboratory / Kakuda Research Center, Japan, Kakuda\nNASDA, Japan, Tokyo
Project summaryThe goal of the Project is to develop methods of laser radiation wavefront forming with extremely low beam pergence and subdiffraction limited accuracy of beam direction. These techniques may prove to be good e.g. for solving problems of energy delivery from Moon to Earth in the scope of the program "XXI century-Energetics" formulated by Japanese government and planned for several tens of years. The proposed approach to optical systems design is based on the use of up-to-date techniques of laser beam wave-front control, adaptive optics and nonlinear optical phase conjugation. Combination of the latest techniques should provide development of optical schematics for forming laser beams with extremely low beam pergence and high accuracy of beam direction control that can be used in various types of lasers differing as by the wavelength so by their mode of operation.
Project tasks comprises the following:
- Analysis of optical problems connected with forming diffraction limited laser beams, coherent summation of laser channels and beam direction control.
- Development of promising architectures for design of optical systems comprising a set of laser modules and laser beam expanders with segmented mirrors to solve the problems of coherent summation of laser channels, compensation for beam distortions and control of overall beam direction using the adaptive optics and nonlinear optics wavefront correction techniques.
- Identification of basic techniques and approaches necessary for forming laser beams, coherent summation of laser channels and beam direction control.
- Theoretical analysis of utmost achievable spatial and energetic parameters of laser beams for the most promising optical schematics.
- Carrying out numerical simulation and verification experiments to demonstrate feasibility of approaches considered.
Approaches to laser optical systems design developed in the scope of the Project as well as software can be used for solution of a number of tasks where low pergence laser beams are necessary, e.g. in long distance space communication and space monitoring.
- Development of promising approaches to the problem of forming laser beams with low beam pergence.
- Elaboration of theoretical approaches, analytical models and software for calculation of parameters of main units and elements of optical schematics for wavefront correction and beam clean up hi low pergence laser beams.
- Identification of optimal techniques for laser beams phase matching as well as parameters of main elements of relevant optical schematics.
- Numerical simulation and identification of achievable beam parameters with the use of methods considered.
- Experimental demonstration of laser beam addressing in the direction determined by the wavefront of a low-power laser beacon with the use of a phase conjugate mirror for compensation for distortions in a model beam director telescope with segmented aperture up to 0.5 m.
- Elaboration of proposals for practical applications of the results.
Technical approach and methodology
To solve the Project tasks a number of known via publications R&D works of ILP in the field of low pergence beam forming will be used, including the following:
- approach to low pergence laser optical systems design based on the scope of the entire laser by pure optical feedback and on elimination of mechanical shifts in the units of wavefront control;
- software for modeling lasers, optical schematics, PC mirrors and processes of propagation of laser radiation in nonlinear media;
- schemes for autocompensation of optical path distortions based on PC and using of holographic diffraction elements on the primary mirror of beam expander or on the secondary mirror;
- principles of design of lasers using PC-mirrors;
- laser design schematics using adaptive optics techniques;
- beam direction control schematics based on novel algorithms;
- schematics for automatic phase matching of laser channels by PC;
- CW, pulse and repetitively pulse laser units (СO2 and solid state lasers);
- PC mirrors of various types for solid-state lasers (SSL) and gas lasers of IR spectral range.
Techniques to be developed for solving Project tasks:
- a technique of comparative analysis of schemes of laser design for radiation transmission;
- a technique of throughout energy efficiency calculation of schemes for autocompensation for distortions of optical path based on PC and holographic diffraction elements;
- techniques for calculation and comparison of achievable laser parameters, PC-mirrors, beam direction control units;
- techniques of design of diode-pumped SSL of "active-mirror" type;
- techniques for carrying out verification experiments;
- techniques for control of direction of the conjugate wave hi schematics with nonlinear-optical phase conjugation.
Potential role of foreign collaborators
The Project was supported by Tohoku University, Japan, and National Aerospace Laboratory (NAL), Japan. Collaborators’ participation in the Project is to discuss a list of problems under expert's analysis and to discuss the conclusions of the expertise and experimental results as well as proposals for further development of works.
We would appreciate also collaboration with other foreign partners in the field of laser optics.
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