From the invention of chirped-pulse amplification almost 30 years ago, rapid advances in short-pulse laser science have enabled numerous new fields of research, many of which have spawned new applications for medical and industrial purposes. Advances in peak power have made possible Petawatt pulses, although at low rates <1 pulse per second and with poor wall-plug efficiency <0.1%. Such limitations are ultimately the result of the solid rod amplifying media employed since the first optical laser in 1960.
The targeted breakthrough for this XCAN project is the realization and integration of the key technologies underpinning a transformative new laser architecture called the Coherent Amplified Network (CAN). Here the conventional rod or slab laser amplifiers are replaced by a large network of coherently combined optical-fibre-based amplifiers. A femtosecond seed laser pulse is repeatedly split and amplified through this network.
The resulting pulses are then recombined coherently with precise individual phase control to produce a single high-average-power beam (see above diagram). The added complexity involved is outweighed by a series of significant advantages including improved beam quality, increasing average power and wall plug efficiency. Furthermore, the ability to address each fibre individually allows very precise control of the final beam's wave front. System noise is also expected to be reduced by the squared-root of the number of channels. The resulting agility in amplitude, phase, focusing and steering enables a heuristic interaction process with the target where in-situ optimization can be achieved. This will be of particular utility for many applications such as complex laser-plasma interactions where even numerical simulations predictions are limited.
The XCAN prototype presents an architecture as illustrated on the figure below.
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