Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
The conceptual design of a multifaceted-mirror ring resonator for the Duke storage ring VUV FEL i... more The conceptual design of a multifaceted-mirror ring resonator for the Duke storage ring VUV FEL is presented. The expected performance of the OK-4 FEL with the ring resonator is described.
Reflectance vs incidence angle measurements have been performed from 24 A to 1216 A on electron-b... more Reflectance vs incidence angle measurements have been performed from 24 A to 1216 A on electron-beam evaporated samples of Ti, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Ir, Os, Pt, and Au, and using a nonlinear least-squares curve-fitting technique, the optical constants have been determined. Independently measured values of the incident beam polarization, film thicknesses, and
Soft apertures have been constructed for tailoring the spatial profile of a light beam to minimiz... more Soft apertures have been constructed for tailoring the spatial profile of a light beam to minimize harmful diffraction effects that lead to self-focusing and consequent damage while still enabling substantial energy extraction from amplifiers.
Free-Electron Generators of Coherent Radiation, 1984
ABSTRACT Optical gain has been detected at 10.6 microns during the recent tapered-wiggler free-el... more ABSTRACT Optical gain has been detected at 10.6 microns during the recent tapered-wiggler free-electron laser amplifier experiment at Los Alamos. In addition, it was possible to measure separately the coherent spontaneous emission at the fundamental and at the second- and third-harmonic wavelengths. Separation of the stimulated gain and coherent spontaneous emission from each other and from the high-power (gigawatt) CO2 laser radiation was possible by use of polarization analysis and passive frequency filtering in hot CO2 gas. The magnitude of the optical gain signals near resonance was consistent with the theoretically predicted gain of about 1 percent. Optical measurements as a function of several parameters of the electron beam (energy and current) and the CO2 laser (power) provided further supporting evidence for the present identifications.
In recent experiments at Los Alamos, free electron laser (FEL) fundamental wavelengths were direc... more In recent experiments at Los Alamos, free electron laser (FEL) fundamental wavelengths were directly observed for the first time from 20 to 45 micron. The 1988 facility's demonstrated wavelength span now extends from 9 to 45 micron. Upgrades are in progress to increase this span. This wavelength region uniquely complements existing FEL applications facilities.
An FEL simulation code, FELEX, for the design of a linac-driven XUV FEL is proposed which is full... more An FEL simulation code, FELEX, for the design of a linac-driven XUV FEL is proposed which is fully three-dimensional in its treatment of the undulator magnetic field, the optical radiation field, and the motion of electrons in the finite-emittance beam. The motion of the electrons and the amplification, diffraction, and the refraction of the light within the undulator magnet are computed self consistently, and the incorporation of propagation of the optical beam and reflection at the mirrors in the model allows a complete laser oscillation solution to be generated. Results of single-pass gain calculations are compared with previous one-dimensional results, and the computed performance parameters of a specific XUV FEL oscillator design are compared with the output of synchrotron radiation sources. It is suggested that multiple-pass calculations may modify single-pass three-dimensional results.
Seven rhesus monkeys (14 eyes) were exposed to 1064-nanometer radiation in single pulses of 25 to... more Seven rhesus monkeys (14 eyes) were exposed to 1064-nanometer radiation in single pulses of 25 to 35 picoseconds fromn a mode-locked Nd: YA G laser. Threshold injury resulted from single pulses with a mnean energy of 13 +/- 3 mnicrojoules. Electron microscopy of the retina revealed that damnage was highly localized in the photoreceptor and pigmented epithelial cells at the oluter retina. Membrane disruption, distorted outer segmtzents, and abnormnal melanin granules resembling fetal premelanosomnies were observed.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1990
A study by numerical simulation of the performance of a multifacet metal mirror ring-resonator FE... more A study by numerical simulation of the performance of a multifacet metal mirror ring-resonator FEL is presented for several XUV wavelengths. Laser performance in the presence of mirror aberrations and thermal distortion is calculated for two different output coupling methods, a scraper mirror and a hole.
A free-electron laser user facility for scientific experimentation in the extreme ultraviolet is ... more A free-electron laser user facility for scientific experimentation in the extreme ultraviolet is being developed at Los Alamos. A series of laser oscillators and amplifiers, driven by a single, RF linear accelerator, will generate broadly tunable, picosecond-pulse, coherent radiation from 1 nm to 400 nm. The design and output parameters of this facility are described, comparison with synchrotron radiation sources is made, and recent progress in developing the three primary components (electron beam, undulator, and resonator mirrors) is reviewed, and various categories of scientific applications are indicated.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
The conceptual design of a multifaceted-mirror ring resonator for the Duke storage ring VUV FEL i... more The conceptual design of a multifaceted-mirror ring resonator for the Duke storage ring VUV FEL is presented. The expected performance of the OK-4 FEL with the ring resonator is described.
Reflectance vs incidence angle measurements have been performed from 24 A to 1216 A on electron-b... more Reflectance vs incidence angle measurements have been performed from 24 A to 1216 A on electron-beam evaporated samples of Ti, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Ir, Os, Pt, and Au, and using a nonlinear least-squares curve-fitting technique, the optical constants have been determined. Independently measured values of the incident beam polarization, film thicknesses, and
Soft apertures have been constructed for tailoring the spatial profile of a light beam to minimiz... more Soft apertures have been constructed for tailoring the spatial profile of a light beam to minimize harmful diffraction effects that lead to self-focusing and consequent damage while still enabling substantial energy extraction from amplifiers.
Free-Electron Generators of Coherent Radiation, 1984
ABSTRACT Optical gain has been detected at 10.6 microns during the recent tapered-wiggler free-el... more ABSTRACT Optical gain has been detected at 10.6 microns during the recent tapered-wiggler free-electron laser amplifier experiment at Los Alamos. In addition, it was possible to measure separately the coherent spontaneous emission at the fundamental and at the second- and third-harmonic wavelengths. Separation of the stimulated gain and coherent spontaneous emission from each other and from the high-power (gigawatt) CO2 laser radiation was possible by use of polarization analysis and passive frequency filtering in hot CO2 gas. The magnitude of the optical gain signals near resonance was consistent with the theoretically predicted gain of about 1 percent. Optical measurements as a function of several parameters of the electron beam (energy and current) and the CO2 laser (power) provided further supporting evidence for the present identifications.
In recent experiments at Los Alamos, free electron laser (FEL) fundamental wavelengths were direc... more In recent experiments at Los Alamos, free electron laser (FEL) fundamental wavelengths were directly observed for the first time from 20 to 45 micron. The 1988 facility's demonstrated wavelength span now extends from 9 to 45 micron. Upgrades are in progress to increase this span. This wavelength region uniquely complements existing FEL applications facilities.
An FEL simulation code, FELEX, for the design of a linac-driven XUV FEL is proposed which is full... more An FEL simulation code, FELEX, for the design of a linac-driven XUV FEL is proposed which is fully three-dimensional in its treatment of the undulator magnetic field, the optical radiation field, and the motion of electrons in the finite-emittance beam. The motion of the electrons and the amplification, diffraction, and the refraction of the light within the undulator magnet are computed self consistently, and the incorporation of propagation of the optical beam and reflection at the mirrors in the model allows a complete laser oscillation solution to be generated. Results of single-pass gain calculations are compared with previous one-dimensional results, and the computed performance parameters of a specific XUV FEL oscillator design are compared with the output of synchrotron radiation sources. It is suggested that multiple-pass calculations may modify single-pass three-dimensional results.
Seven rhesus monkeys (14 eyes) were exposed to 1064-nanometer radiation in single pulses of 25 to... more Seven rhesus monkeys (14 eyes) were exposed to 1064-nanometer radiation in single pulses of 25 to 35 picoseconds fromn a mode-locked Nd: YA G laser. Threshold injury resulted from single pulses with a mnean energy of 13 +/- 3 mnicrojoules. Electron microscopy of the retina revealed that damnage was highly localized in the photoreceptor and pigmented epithelial cells at the oluter retina. Membrane disruption, distorted outer segmtzents, and abnormnal melanin granules resembling fetal premelanosomnies were observed.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1990
A study by numerical simulation of the performance of a multifacet metal mirror ring-resonator FE... more A study by numerical simulation of the performance of a multifacet metal mirror ring-resonator FEL is presented for several XUV wavelengths. Laser performance in the presence of mirror aberrations and thermal distortion is calculated for two different output coupling methods, a scraper mirror and a hole.
A free-electron laser user facility for scientific experimentation in the extreme ultraviolet is ... more A free-electron laser user facility for scientific experimentation in the extreme ultraviolet is being developed at Los Alamos. A series of laser oscillators and amplifiers, driven by a single, RF linear accelerator, will generate broadly tunable, picosecond-pulse, coherent radiation from 1 nm to 400 nm. The design and output parameters of this facility are described, comparison with synchrotron radiation sources is made, and recent progress in developing the three primary components (electron beam, undulator, and resonator mirrors) is reviewed, and various categories of scientific applications are indicated.
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