A multimode (MM) fiber oscillator is configured with MM active fiber doped with light emitters, a pair of MM passive fibers spliced to respective opposite ends of the MM active fiber, and a plurality of MM fiber Bragg gratings (FBG) written in respective cores of the MM passive fibers to provide a resonant cavity. The passive and active fibers are configured with respective cores which are dimensioned with respective diameters matching one another and substantially identical numerical apertures.

A multimode (MM) fiber oscillator is configured with MM active fiber doped with light emitters, a pair of MM passive fibers spliced to respective opposite ends of the MM active fiber, and a plurality of MM fiber Bragg gratings (FBG) written in respective cores of the MM passive fibers to provide a resonant cavity. The passive and active fibers are configured with respective cores which are dimensioned with respective diameters matching one another and substantially identical numerical apertures.

A method for extending and enhancing bright coherent high-order harmonic generation into the VUV-EUV-X-ray regions of the spectrum involves a way of accomplishing phase matching or effective phase matching of extreme upconversion of laser light at high conversion efficiency, approaching 10.sup.3 in some spectral regions, and at significantly higher photon energies in a waveguide geometry, in a self-guiding geometry, a gas cell, or a loosely focusing geometry, containing nonlinear medium. The extension and enhancement of the coherent VUV, EUV, X-ray emission to high photon energies relies on using VUV-UV-VIS lasers of shorter wavelength. This leads to enhancement of macroscopic phase matching parameters due to stronger contribution of linear and nonlinear dispersion of both atoms and ions, combined with a strong microscopic single-atom yield.

A method for extending and enhancing bright coherent high-order harmonic generation into the VUV-EUV-X-ray regions of the spectrum involves a way of accomplishing phase matching or effective phase matching of extreme upconversion of laser light at high conversion efficiency, approaching 10.sup.3 in some spectral regions, and at significantly higher photon energies in a waveguide geometry, in a self-guiding geometry, a gas cell, or a loosely focusing geometry, containing nonlinear medium. The extension and enhancement of the coherent VUV, EUV, X-ray emission to high photon energies relies on using VUV-UV-VIS lasers of shorter wavelength. This leads to enhancement of macroscopic phase matching parameters due to stronger contribution of linear and nonlinear dispersion of both atoms and ions, combined with a strong microscopic single-atom yield.

Systems and methods for that utilize a compressed coherent high intensity X-ray pulse to drive acceleration of particles in a solid medium laser wakefield accelerator (LWFA).

A method and mechanical design for a thin-film diamond crystal mounting apparatus for coherence preservation x-ray optics with optimized thermal contact and minimized crystal strain are provided. The novel thin-film diamond crystal mounting apparatus mounts a thin-film diamond crystal supported by a thick chemical vapor deposition (CVD) diamond film spacer with a thickness slightly thicker than the thin-film diamond crystal, and two groups of thin film thermal conductors, such as thin CVD diamond film thermal conductor groups separated by the thick CVD diamond spacer. The two groups of thin CVD film thermal conductors provide thermal conducting interface media with the thin-film diamond crystal. A piezoelectric actuator is integrated into a flexural clamping mechanism generating clamping force from zero to an optimal level.

Masers and microwave amplifiers that can function in the continuous-wave mode at room temperature are provided. The maser system can include a diamond gain medium having nitrogen-vacancy centers, and a resonator can be disposed around the gain medium. The resonator can be disposed in a cavity box, and radiation (e.g., visible light) can be provided to the gain medium to cause emission of microwave radiation.

An improved solid-state laser for generating sub-200 nm light is described. This laser uses a fundamental wavelength between about 1030 nm and 1065 nm to generate the sub-200 nm light. The final frequency conversion stage of the laser creates the sub-200 nm light by mixing a wavelength of approximately 1109 nm with a wavelength of approximately 234 nm. By proper selection of non-linear media, such mixing can be achieved by nearly non-critical phase matching. This mixing results in high conversion efficiency, good stability, and high reliability.

Embodiments related to pressure sensitive structures are described and depicted.

An injectable wire structure electrode can assimilate with surrounding tissues after injection, inducing in-growth of blood vessels, collagen and other tissue. Assimilation secures the electrode to the tissue without sutures and prevents relative motion which can lead to inflammation and scarring. Associated methods of manufacturing and injection are disclosed, as well as systems including a dermal multiplexer for power delivery.