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Journal ArticleDOI

High-gain inner-shell photoionization laser in Cd vapor pumped by soft-x-ray radiation from a laser-produced plasma source.

01 Nov 1983-Optics Letters (Optical Society of America)-Vol. 8, Iss: 11, pp 551-553
TL;DR: A soft-x-ray-pumped inner-shell photoionization laser has been produced in Cd vapor at 4416 and 3250 A and a reasonably high-energy storage of 0.2 mJ/cm(3) in the upper laser states has been obtained.
Abstract: A soft-x-ray-pumped inner-shell photoionization laser has been produced in Cd vapor at 4416 and 3250 A. A gain of 5.6 cm−1 has been measured at 4416 A, and a reasonably high-energy storage of 0.2 mJ/cm3 in the upper laser states has been obtained.
Citations
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Journal ArticleDOI
26 Jan 2012-Nature
TL;DR: The implementation of an X-ray laser in the kiloelectronvolt energy regime, based on atomic population inversion and driven by rapid K-shell photo-ionization using pulses from anX-ray free-electron laser is described, which provides greatly increased wavelength stability, monochromaticity and improved temporal coherence by comparison with present-day X- Ray free-Electron lasers.
Abstract: Since the invention of the laser more than 50 years ago, scientists have striven to achieve amplification on atomic transitions of increasingly shorter wavelength. The introduction of X-ray free-electron lasers makes it possible to pump new atomic X-ray lasers with ultrashort pulse duration, extreme spectral brightness and full temporal coherence. Here we describe the implementation of an X-ray laser in the kiloelectronvolt energy regime, based on atomic population inversion and driven by rapid K-shell photo-ionization using pulses from an X-ray free-electron laser. We established a population inversion of the Kα transition in singly ionized neon at 1.46 nanometres (corresponding to a photon energy of 849 electronvolts) in an elongated plasma column created by irradiation of a gas medium. We observed strong amplified spontaneous emission from the end of the excited plasma. This resulted in femtosecond-duration, high-intensity X-ray pulses of much shorter wavelength and greater brilliance than achieved with previous atomic X-ray lasers. Moreover, this scheme provides greatly increased wavelength stability, monochromaticity and improved temporal coherence by comparison with present-day X-ray free-electron lasers. The atomic X-ray lasers realized here may be useful for high-resolution spectroscopy and nonlinear X-ray studies.

304 citations

Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the plasma-based x-ray lasers which have already demonstrated saturated amplification whose wavelengths are between 50 and 6?nm and proposed a future direction for X-ray laser researches.
Abstract: In this paper, the author reviews the plasma-based x-ray lasers which we have already demonstrated saturated amplification whose wavelengths are between 50 and 6?nm. Section?1 describes the motivation of this review paper which includes basic ideas, developments and their applications of x-ray lasers. In section?2, the author describes the early x-ray laser researches on the recombination and the electron collisional excitation schemes including the hydrogen-like and lithium-like ion recombination schemes and the electron collisional excitation scheme. Section?3 describes the first demonstration of significant lasing at Livermore for the electron collisional excitation scheme of neon-like selenium ions at a wavelength of 20.6 and 20.9?nm and Princeton for the recombination scheme of hydrogen-like carbon ions at a wavelength of 18.2?nm. In section?4, the author describes the electron collisional excitation type soft x-ray lasers which are at present the most successful x-ray lasers. The subjects with which the author deals are saturated amplification neon-like soft x-ray lasers, improvement of neon-like soft x-ray laser performance using multi-layer mirrors, atomic physics issues of the neon-like soft x-ray lasers, gain guiding of the x-ray laser beam propagation, discharge-pumped compact repetitive neon-like ion soft x-ray lasers, the collisional excitation nickel-like ion soft x-ray lasers, high gain and saturated amplification nickel-like soft x-ray lasers at wavelengths as short as 7?nm, the short wavelength nickel-like x-ray lasers whose wavelengths are close to the longest wavelength edge the water window of 4.4?nm, transient collisional excitation scheme which is currently the most popular soft x-ray lasers pumped by short-pulse compact lasers with a laser energy of a few J to a few tens of?J. In section?5, the author describes various plasma-based x-ray laser schemes other than the recombination and the collisional schemes, such as the optical field ionization schemes and inner-shell ionization schemes. Section?6 includes soft x-ray laser applications such as soft x-ray holography, soft x-ray interferometers, soft x-ray microscopy and other applications. In section?7, the author summarizes this review paper and he proposes a future direction for x-ray laser researches.

209 citations

Journal ArticleDOI
TL;DR: In this paper, the issues surrounding the origin and characteristics of laser-plasma continuum light sources are discussed, and progress to date on the application of these sources to the study of the X-UV photoabsorption spectra of atoms, ions and molecules.
Abstract: Exteme-ultraviolet (X-UV) absorption spectroscopy has gained impetus in recent years, spurred on by a growing interest in the physics of core excited atomic, molecular and solid species. Progress in this field has been helped in no small measure by developments in X-UV light sources. One such source is the laser-produced plasma which, by suitable choice of target material, can be used to produce a clean, line free continuum virtually throughout the X-UV and V-UV spectral regions from 40-2000 ?. We briefly address here the issues surrounding the origin and characteristics of laser-plasma continuum light sources. In addition we review progress to date on the application of these sources to the study of the X-UV photoabsorption spectra of atoms, ions and molecules.

96 citations

Journal ArticleDOI
TL;DR: The creation of a population inversion on the K-alpha transition of neon at 1.5 nm is examined by using the photoionization scheme first suggested by Duguay and Rentzepis in 1967 to verify the potential feasibility of this scheme.
Abstract: Recent advances in the production of ultrashort x-ray pulses by using femtosecond laser-produced plasmas coupled with the development of terawatt ultrashort-pulse lasers may make possible ultrashortpulse photoexcited x-ray lasers. I examine the creation of a population inversion on the K-alpha transition of neon at 1.5 nm by using the photoionization scheme first suggested by Duguay and Rentzepis in 1967. It is shown that this laser can be produced by using a pump laser of ~ 10 J in 50 fs, provided that a sufficiently bright laser-produced plasma x-ray source can be created. Recent experimental and theoretical results are discussed that verify the potential feasibility of this scheme.

65 citations

Book ChapterDOI
01 Jan 1992
TL;DR: In this paper, the application of stimulated Raman scattering as a practical method for the generation of tunable, coherent radiation is described, with particular emphasis on molecular hydrogen and various atomic systems.
Abstract: This chapter describes the application of stimulated Raman scattering as a practical method for the generation of tunable, coherent radiation A brief theoretical discussion of the stimulated Raman effect in the steady state and transient-scattering regimes is presented Generation techniques are described in detail, with particular emphasis on molecular hydrogen and various atomic systems, as Stokes and anti-Stokes Raman scattering media Finally, several effects that limit Raman conversion efficiencies are discussed

56 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the ejection of electrons from inner shells of atoms through photoionization is suggested as a straightforward means of creating population inversions at vacuum uv and x-ray wavelengths.
Abstract: The ejection of electrons from inner shells of atoms through photoionization is suggested as a straightforward means of creating population inversions at vacuum uv and x‐ray wavelengths. This can be accomplished by photon sources covering broad bands. Sodium vapor and solid copper are examined as possible candidates for laser action at 372 A and 1.54 A, respectively. A first‐rise traveling wave pump must be used; pumping powers required for superradiant operation run into several gigawatts, with rise times ranging from 10−9 sec in the near‐vacuum uv to 10−15 sec in the x‐ray region.

179 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used the yttrium aluminum garnet laser beam (1.06 μm) to photoionize neutral Li vapor to produce Li+ metastables.
Abstract: Soft x rays from a plasma generated by a neodymium: yttrium aluminum garnet laser beam (1.06 μm) are used to photoionize neutral Li vapor to produce Li+ metastables. Maximum metastable densities of Li+ (1s2s) 1S=6×1014 ions/cm3 and Li+ (1s2s) 3S=3×1015 ions/cm3 are obtained. The effective lifetimes of these levels are measured to be approximately 5 ns. At 50 mJ of incident laser energy the inferred conversion efficiency from 1.06‐μm radiation to soft x rays is ∼14%.

33 citations

Journal ArticleDOI
TL;DR: In this article, the energy dependences of photoionization cross sections to produce Cd+, Cd2+, and Zn2+ have been measured with modulated atomic beams and pulsed, dispersed vacuum-ultraviolet radiation.
Abstract: The energy dependences of the photoionization cross sections to produce Cd+, Cd2+, and Zn2+ have been measured with modulated atomic beams and pulsed, dispersed vacuum‐ultraviolet radiation. Results are presented for cadmium ions at energies between 8.99 and 83 eV and for zinc ions at energies between 27.35 and 65 eV.

32 citations

Journal ArticleDOI
TL;DR: In this article, a two-stage optical-pumping scheme was proposed for achieving laser action on the 199-A lithium ion resonance line, where a dye laser was used as a traveling-wave excitation source, providing a collinea...
Abstract: A two‐stage optical‐pumping scheme is considered for achieving laser action on the 199‐A lithium‐ion resonance line. Incoherent radiation from a CO2 laser‐produced plasma preferentially photoionizes the K shell of neutral lithium, producing highly energetic ions in the metastable 1s2s state. A detailed model of the system indicates that with an initial lithium vapor density ∼1014 cm−3, an effective metastability of several nsec can be obtained, allowing a drastic reduction in pumping requirements compared to schemes involving direct pumping of the upper laser level. After a sufficient buildup of metastable ions, a dye laser, tuned to the 9584‐A 1s2s 1S→1s2p 1P transition, is switched on, and lasing at 199 A occurs due to the stimulated‐resonant‐Raman anti‐Stokes process. At 1014 cm−3 initial vapor density, the resonant‐Raman gain is ∼10 cm−1, so that a gain length ∼3 cm should be adequate to demonstrate lasing in a single pass. The dye laser acts as a traveling‐wave excitation source, providing a collinea...

27 citations

Journal ArticleDOI
TL;DR: In this paper, mode locking of the He-Cd laser was achieved at 4416 and 3250 A using an intracavity acoustic loss modulator, with a peak power greater than 1.6 W.
Abstract: Mode locking of the He–Cd laser has been achieved at 4416 and 3250 A using an intracavity acoustic loss modulator. Pulses narrower than 150 psec with a peak power greater than 1.6 W were obtained at 4416 A when a special Cd isotope mixture was used. Pulses of the order of 400 psec with a peak power of 0.1 W were obtained at 3250 A using naturally occurring Cd.

18 citations