Five conical harmonic beams are generated from the interaction of femtosecond mid-infrared (mid-IR) pulses at a nominal input wavelength of 1997 nm with a 2D LiNbO3 nonlinear photonic crystal with Sierpinski fractal superlattices. The main diffraction orders and the corresponding reciprocal vectors involved in the interaction are ascertained. Second and third harmonics emerging at external angles of 23.82° and 36.75° result from nonlinear ?erenkov and Bragg diffractions, respectively. Three path

We propose a spatial diffraction diagnostic method via inserting a millimeter-gap double slit into the collimated terahertz beam to monitor the minute variation of the terahertz beam in strong-field terahertz sources, which is difficult to be resolved in conventional terahertz imaging systems. To verify the method, we intentionally fabricate tiny variations of the terahertz beam through tuning the iris for the infrared pumping beam before the tilted-pulse-front pumping setups. The phenomena can

It is well known that a light spot of sub-wavelength will diverge in all directions. In this letter, A method is presented for generating sub-wavelength (0.44\lambda) longitudinally polarized beam, which propagates without divergence over lengths of about 2\lambda in free space. This is achieved by a high numerical aperture (NA) lens axicon that utilizes spherical aberration to duplicate the performance of an axicon and to create an extended focal line.

Diffraction loss for several solid shapes with GTD-UTD.zip

这是A.P.Stokseth 的文章： "Properties of a defocused optical system"的MATLAB实现。

Keller于1961年在美国光学协会学报上发表的经典之作，衍射光学