Zhongwei Fan | PubMed Health

PubMed2006

Pulse compression beyond the Fourier-transform limit.

Theories of a technique for compression of an ultrashort femtosecond laser pulse beyond its Fourier-transform limit based on the pulse shaping technique are proposed. The technique is called superresolution in time domain (STD). Global optimization theories for the design of a mask to modulate the spectrum of an input pulse to obtain a STD output pulse are proposed. Several design examples illustrate the feasibility of STD. Some fundamental limits of STD are also provided.

Journal Article↗

PubMed2006

Optical superresolution of focused partially spatially coherent laser beams.

We report design theories of a diffractive superresolution element (DSE) to implement optical superresolution of focused partially spatially coherent laser beams. The design problem of the DSE can be transformed into a problem of linear programming to obtain a globally optimal solution. By using the design theories, some fundamental limits of optical superresolution of focused partially spatially coherent laser beams are proposed, and several design examples are provided. As expected, both the fundamental limits and the design examples show that worse spatial coherence will cause worse superresolution performance. The design theories provide a design approach with partially coherent beams and may be useful for other design problems under partially coherent illumination.

Journal Article↗