Crystalline microundulator

A theory of radiation in a crystalline microundulator is developed. It is shown that crystalline microundulators may be used as effective alternative radiation sources in the wavelength range λ=0.1–1.0 Å.     

Multicrystal X-ray diffraction of heteroepitaxial structures

An appraisal of high-resolution multi-crystal multi-reflection diffractometry (HRMCMRD) and topography is presented to illustrate its potential for structure analysis. Examples of methods for extracting lateral interface roughness, studying layered structures with imperfect epitaxy (including strained layer structures) are given to show the wealth of information available from X-ray techniques. The advantages of diffraction space mapping are discussed in addition to the use of topography to interpret the diffuse and Bragg scattering. The HRMCMRD has a dynamic range of 10⁶ and can record topographs with intensities less than 1 count/s.     

Multicrystal designs for efficient third-harmonic generation

Efficient frequency tripling of high-fluence, narrow-band laser pulses is routinely accomplished with a doubling crystal and a sum-frequency mixer. The addition of a second mixer can dramatically improve conversion efficiencies for the large bandwidths of interest for inertial confinement fusion. Designs that involve two doublers similarly offer a higher dynamic range of conversion efficiency versus intensity than the usual two-crystal design.     

Multicrystal, continuous-wave, single-pass second-harmonic generation with 56% efficiency

We report a simple and compact implementation for single-pass second-harmonic-generation (SP-SHG) of cw laser radiation, based on a cascaded multicrystal (MC) scheme, that can provide the highest conversion efficiency at any given fundamental power. By deploying a suitable number of identical 30-mm-long MgO:sPPLT crystals in a cascade and a 30W cw Yb-fiber laser at 1064nm as the fundamental source, we demonstrate SP-SHG into the green with a conversion efficiency as high as 56% in the low-power as well as the high-power regime, providing 5.6W of green output for 10W and 13W of green output for 25.1W of input pump power. The MC scheme permits substantial increase in cw SP-SHG efficiency compared to the conventional single-crystal scheme without compromising performance with regard to power stability and beam quality.