The output energy (90 μJ), focal spot diameter (235 μm), and pointing accuracy (±75 μrad) for a 3.7-cm-long Se soft x-ray laser operating at 20.6 and 20.9 nm are reported. Now that this intense soft x-ray source has been well characterized it may find use in such diverse applications as lithography, contact microscopy, holography, and photoionization pumping.

The efficiency, duration, and spectral content of the emission from laser-produced Ta plasmas in the 10–71 nm spectral region have been measured for laser pulse durations ranging from 100 fs to 70 ps. Efficiencies from 0.3% for 100 fs pulses to 2.65% for 70 ps pulses, x-ray pulse durations from less than 10 ps for 100 fs excitation pulses to 105 ps for 70 ps excitation pulses, and spectral content peaking in the 17–35 nm region were measured for 1 mJ pulses at intensities from 1011 to 5×1014 W/cm2.

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text O. R. WOOD, W. T. SILFVAST, H. W. K. TOM, W. H. KNOX, R. L. FORK, C. H. BRITO-CRUZ, P. J. MALONEY, and C. V. SHANK, "Soft x rays produced by subpicosecond target irradiance," in International Quantum Electronics Conference, T. Hansch, D. Grischkowsky, D. Pritchard, and C. Shank, eds., Vol. 21 of OSA Technical Digest (Optica Publishing Group, 1987), paper MAA2. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

A 140-mJ 100-ps duration 1.06-µm laser, focused with a cylindrical lens to a 1-cm line on a Ta target at an intensity of 6 × 1010 W/cm2, produced sufficient XUV and soft-x-ray flux to obtain large inversions via inner-shell photoionization of Cd (Ref. 1) and Xe.2 The short-wavelength emission from the Ta plasma is believed to result from a large number of transitions Ta VI predominantly in the 15–19-nm region. This is based primarily on spectral data in the 10–40-nm region produced by long-pulse (25-ns) irradiation of Ta (Ref. 3) and is confirmed by observation of strong Ta V recombination line emission in the 80–90-nm region in the current work. The Ta flux in the 15–19-nm spectral range is estimated to be of the order of 1026 photons/s, which is sufficient to produce the large inversions observed in Cd and Xe.

The soft-x-ray and XUV emission from laser-produced plasmas produced by 300-mJ pulses from 1.06- and 10.6-μm lasers was compared both by measuring the absorption due to inner-shell photoionization in Cd vapor in the 10–71-nm region and by directly observing the plasma emission in the 35–75-nm region. The results indicate that a 10.6-μm laser can be a more efficient pumping source for a photoionization laser than a 1.06-μm laser in the nanosecond pulse regime at low laser intensities.

We report the first known demonstration of a novel bistable optical device that switches an interface between reflecting and transmitting states. Our results are in agreement with a simple graphical analysis.

We present the derivation of scaling relationships that describe the behavior of liquid suspensions of dielectric spheres as nonlinear optical media and report results of four-wave mixing experiments that are in good agreement with these predictions.

We describe a degenerate four-wave mixing technique for measuring optical Kerr coefficients. This technique permits discrimination between fast and slow (thermal) nonlinearities. We report results for a number of long-chain organic materials.

We describe the results of a detailed experimental study of the reflectivity of a nonlinear interface under the influence of intense ruby laser pulses incident in a Gaussian beam at grazing angles. The nonlinear interface was the interface between a linear optical material (glass) and a nonlinear material with a positive optical Kerr coefficient (CS2). Optical hysteresis was observed as a function...

This paper summarizes the work done on transversely excited (TE) waveguide lasers since the first proposal in 1973 and reports on the current state of the art. We describe the development of waveguide designs and of techniques for discharge control which permit high-pressure operation and high output power densities to be obtained.

We describe the development of a powerful and efficient TE CO2 waveguide laser. With a 20 cm long waveguide, the device provides 175 W, 20 μs duration output pulses at 3.7 percent efficiency or 20 W of average power at 3.1 percent efficiency. This output power is nearly five times greater than that previously obtained from a TE CO2 waveguide laser. These improvements were obtained by careful control of the electric field to pressure ratio through preionization.

Under suitable conditions, the boundary between a linear and a nonlinear (Kerr effect) medium should have a reflection coefficient which exhibits hysteresis as a function of optical intensity. We present the first experimental evidence of this effect. Experiments were performed using ∼1-ns ruby laser pulses incident on a glass-CS2 boundary.

We have developed a particularly rugged waveguide TE CO2 laser structure that can be usefully operated in several distinctly different discharge modes. A short-pulse mode provides 0.4-μsec-duration gain-switched pulses, a quasicontinuous mode provides 20-μsec output pulses of over 200 W/cm3 of discharge volume, and the high-average power mode provides average power outputs of over 17 W/cm3.