A set of optical elements for optical extraction composed of packed expanding optical cross sections to efficiently extract from a large gain region. The elements are rectangular shaped concave small expansion lenses matched to rectangular convex collimating lenses. Absorbing sheets divide an overall large volume up into smaller volumes to minimize losses due to amplified spontaneous emission. This arrangement has various applications, particularly in inertial confinement technology, where it may be used to extract energy from KrF laser media energized by electron beams. For certain applications, this regime of the gain medium may have zones at the absorbing sheets where this is no gain.

Employing undulator devices as x-ray radiation sources requires expensive and bulky support systems for operation, which are not robust and lead to limited ranges of generated radiation energies. A force-compensated undulator device is described. The device includes an undulator having first and second magnet arrays disposed along a central axis. The first magnet array is translatable along the central axis. The device further includes a compensator unit disposed adjacent to the first magnet array with the compensator unit having a first row of magnets disposed along a compensator axis with the compensator axis being parallel to the central axis, and a second row of magnets disposed along the compensator axis. The first row of magnets is translatable along the compensator axis. The compensator provides magnetic forces that neutralize the system dynamic magnetic forces generated by the undulator.

Employing undulator devices as x-ray radiation sources requires expensive and bulky support systems for operation, which are not robust and lead to limited ranges of generated radiation energies. A force-compensated undulator device is described. The device includes an undulator having first and second magnet arrays disposed along a central axis. The first magnet array is translatable along the central axis. The device further includes a compensator unit disposed adjacent to the first magnet array with the compensator unit having a first row of magnets disposed along a compensator axis with the compensator axis being parallel to the central axis, and a second row of magnets disposed along the compensator axis. The first row of magnets is translatable along the compensator axis. The compensator provides magnetic forces that neutralize the system dynamic magnetic forces generated by the undulator.

A method for varying the wavelength of a free electron laser (FEL) by applying an energy dither to the charged particles supplying the FEL. Bunches of charged particle beams are accelerated by cavities that are operated at a harmonic of the bunch repetition rate. The method involves adding one or more secondary radiofrequency accelerator cavities after the primary beam transport and near the wiggler to apply a fluctuation between individual bunches with a pseudo-random distribution. The secondary radiofrequency accelerator cavities provide fine variations of the beam energy about a nominal operating point. Operating a free electron laser (FEL) with a 1% change in the electron beam energy via the added secondary cavities will result in a 2% wavelength variation of the FEL output.

A method for varying the wavelength of a free electron laser (FEL) by applying an energy dither to the charged particles supplying the FEL. Bunches of charged particle beams are accelerated by cavities that are operated at a harmonic of the bunch repetition rate. The method involves adding one or more secondary radiofrequency accelerator cavities after the primary beam transport and near the wiggler to apply a fluctuation between individual bunches with a pseudo-random distribution. The secondary radiofrequency accelerator cavities provide fine variations of the beam energy about a nominal operating point. Operating a free electron laser (FEL) with a 1% change in the electron beam energy via the added secondary cavities will result in a 2% wavelength variation of the FEL output.

A method for applying an energy dither to a charged particle beam in order to vary the wavelength of the charged particle beam. Bunches of charged particle beams are accelerated by cavities that are operated at a harmonic of the bunch repetition rate. One or more secondary radiofrequency accelerator cavities are added near the wiggler after the primary beam transport to apply a fluctuation between individual bunches with a pseudo-random distribution. The secondary radiofrequency accelerator cavities provide fine variations of the beam energy about a nominal operating point. Operating a free electron laser (FEL) with a 1% change in the electron beam energy via the secondary cavity will result in a 2% wavelength variation of the FEL output.

A method for applying an energy dither to a charged particle beam in order to vary the wavelength of the charged particle beam. Bunches of charged particle beams are accelerated by cavities that are operated at a harmonic of the bunch repetition rate. One or more secondary radiofrequency accelerator cavities are added near the wiggler after the primary beam transport to apply a fluctuation between individual bunches with a pseudo-random distribution. The secondary radiofrequency accelerator cavities provide fine variations of the beam energy about a nominal operating point. Operating a free electron laser (FEL) with a 1% change in the electron beam energy via the secondary cavity will result in a 2% wavelength variation of the FEL output.

A method for varying the wavelength of a free electron laser (FEL) by applying an energy dither to the charged particles supplying the FEL. Bunches of charged particle beams are accelerated by cavities that are operated at a harmonic of the bunch repetition rate. The method involves adding one or more secondary radiofrequency accelerator cavities after the primary beam transport and near the wiggler to apply a fluctuation between individual bunches with a pseudo-random distribution. The secondary radiofrequency accelerator cavities provide fine variations of the beam energy about a nominal operating point. Operating a free electron laser (FEL) with a 1% change in the electron beam energy via the added secondary cavities will result in a 2% wavelength variation of the FEL output.

A method for varying the wavelength of a free electron laser (FEL) by applying an energy dither to the charged particles supplying the FEL. Bunches of charged particle beams are accelerated by cavities that are operated at a harmonic of the bunch repetition rate. The method involves adding one or more secondary radiofrequency accelerator cavities after the primary beam transport and near the wiggler to apply a fluctuation between individual bunches with a pseudo-random distribution. The secondary radiofrequency accelerator cavities provide fine variations of the beam energy about a nominal operating point. Operating a free electron laser (FEL) with a 1% change in the electron beam energy via the added secondary cavities will result in a 2% wavelength variation of the FEL output.

An edge emitting structure includes an active region configured to generate radiation in response to excitation by a pumping beam incident on the structure. A front facet of the edge emitting structure is configured to emit the radiation generated by the active region. A metallic reflective coating disposed on at least one of the front and rear facets of the edge emitting structure. The metallic reflective coating is configured to reflect the radiation generated by the active region.