Spatio-temporal couplings (STCs) play a vital role in the transport and compression of an ultrashort pulsed beam. Although STCs can be useful in optimizing nonlinear processes and generating an attosecond pulse, those couplings can lead to a strong reduction of intensity on the target in high power laser system. 

In a recent study, the research group from State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics (SIOM) of Chinese Academy of Sciences (CAS) modified the 6×6 matrix formalism to describe a Gaussian pulse diffracted by a reflecting grating with arbitrary orientation. The result was published on Optics Express.

In their experiment, as an application example, the spatio-temporal evolution of a Gaussian pulsed beam at 800 nm in a duplex grating compressor (DGC) was studied. Several kinds of first-order STCs were revealed by the spatio-temporal transfer matrix. The study provided a complete analysis toward spatial-temporal distortion in this new compressor design. The feasibility of DGC setup in high peak power laser system was proved.

Moreover, the matrix treatment showed its capacity in analyzing not only DGC setup but also classical/misaligned compressor, and therefore provided a general framework for all those grating-based compressor setups.

The matrix formalism directly establishes the connection between compressor design and spatial-temporal structure of the pulse; and therefore it can directly reveal all the possible first-order STCs which benefits the design and optimization of a grating-based compressor.

The work was supported by the Strategic Priority Research Program of CAS, International S&T Cooperation Program of China, Program of Shanghai Academic/Technology Research Leader, and Shanghai Municipal Science and Technology Major Project.

Generic case of diffraction on a grating. (Image by SIOM)

Article website:
https://www.osapublishing.org/oe/abstract.cfm?uri=oe-27-22-31667
Contact:
Mr. Cao Yong
General Administrative Office
Shanghai Institute of Optics and Fine Mechanics, CAS
Email: caoyong@siom.ac.cn