The chirp of single-cycle microwave fields after interaction with pairs of parallel diffraction gratings is measured in a phase-sensitive terahertz spectrometer. Novel transmission grating pairs recently proposed by Tournois, which combine diffraction and refraction effects, yield an almost linear group delay over a bandwidth that exceeds that of conventional reflection gratings by a factor of ...

A new technique and a physical model for writing extremely short length Bragg gratings in optical fibers have been developed. The model describes the effects of diffraction on the spatial spectra and therefore, the wavelength spectra of the Bragg gratings. Using an interferometric technique and a variable aperture, short gratings of various lengths and center wavelengths were written in optical...

We have developed a new type of soft x-ray diffraction grating. This critical-angle transmission (CAT) grating combines the advantages of traditional transmission gratings (low mass, extremely relaxed alignment and flatness tolerances) with those of x-ray reflection gratings (high efficiency due to blazing in the direction of grazing-incidence reflection, increased resolution due to the use of ...

Diffraction gratings affect the absolute phase of light in a way that is not obvious from the usual derivation of optical paths using the grating equation. For example, consider light which encounters first one and then the second of two parallel gratings. If one grating is moved parallel to its surface, the phase of the light diffracted from the grating pair is shifted by 2pi each time the gra...

We report the formation of thin anisotropic phase gratings in a nematic liquid-crystalline film by use of lateral (fringing) electric fields induced by transparent interdigitated electrodes. These gratings yield high diffraction efficiency (>30%) with a strong dependence on the readout beam incidence angle. In addition, the formation of a defect wall is observed that has a significant effect on...

In this paper, the laser recording of thin diffraction gratings in deoxyribonucleic acid (DNA) – cetyltrimethyl-ammonium chloride (CTMA) surfactant doped with Rhodamine 610 (Rh610) films is experimentally investigated. The diffraction efficiency of the gratings induced in dye-doped DNA films by the interference of two Ar laser beams at 514.5 nm wavelength is monitored using a He-Ne probe beam (...

We demonstrate tunable, fluidic, two-dimensional diffraction gratings based on a microfluidic platform comprising a flow-focusing bubble generator and flowing, regular lattices of bubbles formed by dynamic self-assembly. The structure of these lattices can be tuned with switching times of less than ten seconds by changing the pressures and rates of flow applied to the device. These diffraction ...