High repetition rate operation of saturated tabletop soft x-ray lasers in transitions of neon-like ions near 30 nm

Abstract

Abstract:We report average powers exceeding 1 microwatt in laser transitions of Ne-like ions at wavelengths near 30 nm. Gain-saturated operation was obtained at a repetition rate of 5 Hz exciting solid targets with pump pulses of ~1 J energy and 8 ps duration impinging at grazing incidence of 20 degrees. Gain-length products of about 20 were obtained in the 30.4 nm and 32.6 nm transitions of Ne-like V and Ne-like Ti respectively. Strong lasing was also observed in Ne-like Cr at 28.6 nm and in the 30.1 nm line of Ne-like Ti.

Continuous high-repetition-rate operation of collisional soft-x-ray lasers with solid targets

“…7,8 Recently, the laser pump energy required for obtaining gainsaturated operation of soft-x-ray lasers was significantly reduced by directing the picosecond pump pulse at a grazing angle of incidence into the precreated plasma. [9][10][11][12][13][14] The use of picosecond-duration pump laser pulses with energies up to 1 J impinging at grazing incidence angles from 14°to 23°resulted in the demonstration of gain-saturated lasers in transitions of Ni-like ions [9][10][11][12] and Ne-like ions 13 at wave- Herein we report the quasi-continuous operation of a saturated 13.9 nm Ni-like Ag soft-x-ray laser at a 5 Hz repetition rate, using a scheme that will allow uninterrupted soft-x-ray laser output at a repetition rate of 10 Hz for a period of hours. An average power of 2 W and a high average spectral brightness of 1.3ϫ 10 13 photons mm −2 mrad −2 s −1 ͑0.1% bandwidth͒ −1 at 13.9 nm was demonstrated.…”

Gain-saturated 109 nm tabletop laser operating at 1 Hz repetition rate

“…Of particular interest is the development of gainsaturated lasers that can be fired repetitively, producing the average power required for many applications. Both capillary discharges and laser-created plasmas have been successfully used to demonstrate gain-saturated collisionally excited tabletop lasers that operate at wavelengths between 46.9 and 13.2 nm at repetition rates of several hertz [1][2][3][4][5][6][7][8][9][10]. However, the steep wavelength scaling of the energy necessary to pump such lasers imposes a challenge to the demonstration of gain-saturated high-repetitionrate lasers at shorter wavelengths.…”

“…The plasma is assumed to be created by a sequence of two 210 ps duration prepulses with intensities of 4.8ϫ 10 10 W cm −2 and 1.8ϫ 10 12 W cm −2 separated by 5.6 ns, and to be subsequently transiently heated with a 5 ps FWHM duration pulse with an intensity of 9.8ϫ 10 13 W cm −2 impinging at 30 deg grazing incidence. This pumping geometry, which is inherently a traveling wave, takes advantage of the refraction of the pump beam in the electron density gradient of the precreated plasma to efficiently deposit energy into a plasma density region with optimum conditions for amplification [3][4][5][6][8][9][10]13]. The first laser pulse is responsible for creating the ion density profile, and the second laser pulse heats the plasma, ionizing 40% of the ions into the nickel-like state over a relatively broad region [ Fig.…”

High Repetition Rate Collisional Soft X-Ray Lasers Based on Grazing Incidence Pumping

“…This geometry preferentially heats a selected region of the precreated plasma with optimum density for soft X-ray amplification [16]- [22]. This pumping configuration, that is inherently traveling wave, takes advantage of the refraction of the pump beam to increase the interaction length of the rays in the gain region of the plasma [ Fig.…”

“…1], thereby increasing the fraction of the pump energy absorbed in that region. Pumping of the 18.9-nm line of Ni-like Mo at 14 grazing incidence with 150 mJ of total pumping energy from a 10-Hz laser was reported to generate a gain-length product of 14 [18], and the use of 1-J heating pulses at angles of incidence between 14 and 23 resulted in the demonstration of gain-saturated 5-Hz repetition rate lasers in transitions of Ni-like ions [19]- [21] and Ne-like ions [22] at wavelengths as short as 13.9 nm for Ni-like Ag [21]. (a) Schematic representation of the grazing incidence pump geometry configuration.…”