Object–image-grating self-tiling to achieve and maintain stable, near-ideal tiled grating conditions

Abstract

We propose and demonstrate an object-image-grating self-tiling method for doubling the effective aperture of a grating by tiling it with its image to form an object-image-grating pair. With the aid of the object-image relation, the line-density variation, angular tip, and longitudinal piston errors within a tiled grating no longer exist. The method helps achieve and maintain a near-ideal tiled grating by using a simple far-field method. Because one tiled grating requires only one beam line, a single probe laser can be used for first-installation adjustments and long-term maintenance monitoring, with no wavelength or incident angle limitations.

Further Development of the Short‐Pulse Petawatt Laser: Trends, Technologies, and Bottlenecks

“…Due to the limited size and low damage threshold of diffraction gratings, [169][170][171][172][173][174] tiled gratings are frequently used in the compressors of picosecond and femtosecond CPA lasers. [175][176][177][178][179][180][181][182][183][184][185][186][187][188] Figure 14a schematically shows when two gratings are tiled to form a size-doubled one, six tiling errors of three rotations (tilt, tip, and rot), two moves (shift and piston), and one fabrication difference (Δd) will degrade the tiling result, as well as the pulse compression and beam focusing. [175][176][177][178][179][180][181][182][183] Figure 14b illustrates a new method of object-image-grating self-tiling invented in 2010, [184][185][186][187][188] and different from directly tiling two real gratings, a grating (object grating) is tiling with its image (image grating) formed by a perpendicularly positioned mirror.…”

“…With the help of the object-image relationship (i.e., mirror movement), six tiling errors are reduced to only three of two rotations (tilt and rot) and one move (shift), and more importantly, the left three tiling errors can be directly detected by observing three kinds of distortions of the focal spot. [184,187] In this case, the requirements of detection and control are reduced a lot, and compared with the traditional method usually used in picosecond CPA lasers, the new method can be used in femtosecond CPA lasers. [186,187] Recently, this method has already been successfully applied in the 1500 J, 150 fs grating compressor in the L4 beamline of ELI-Beamlines (Czech Republic) to double the effective sizes of the second and third gratings.…”

“…[175][176][177][178][179][180][181][182][183][184][185][186][187][188] Figure 14a schematically shows when two gratings are tiled to form a size-doubled one, six tiling errors of three rotations (tilt, tip, and rot), two moves (shift and piston), and one fabrication difference (Δd) will degrade the tiling result, as well as the pulse compression and beam focusing. [175][176][177][178][179][180][181][182][183] Figure 14b illustrates a new method of object-image-grating self-tiling invented in 2010, [184][185][186][187][188] and different from directly tiling two real gratings, a grating (object grating) is tiling with its image (image grating) formed by a perpendicularly positioned mirror. With the help of the object-image relationship (i.e., mirror movement), six tiling errors are reduced to only three of two rotations (tilt and rot) and one move (shift), and more importantly, the left three tiling errors can be directly detected by observing three kinds of distortions of the focal spot.…”

Application problems of object-image-grating self-tiling in ultra-short pulse lasers

“…In this condition, the grating tiling (GT) technique is proposed to solve this problem, but its high complexity and low reliability challenges its actual use in such laser systems [2]. Then, an improved technique named object-imagegrating self-tiling (OIGST) is presented aimed to enlarge the effective grating size conveniently and efficiently [3].…”

Research on potential problems of object image grating self-tiling for applications in large aperture optical systems

“…In fact, these methods do not eliminate the first factor, and their actual applications are limited by the complicated experimental setups and alignment procedures. In this situation, an object image grating self-tiling configuration was presented by our group [25], which could completely eliminate three tiling errors (grating period difference, angular tip, and longitudinal piston) in six, and thereby achieve and maintain a near ideal tiled grating only by a simple far-field method. Moreover, the far-field method just needs a monochromatic laser with no wavelength or incident angle limit.…”