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Submillimeter-wave (SMMW) laser action with gaseous sulfur dioxide has previously been obtained on three transitions of the optically pumped cw laser [1], and on ten transitions of the electric discharge laser [2]. We report 15 additional transitions of the optically pumped laser.

The wavelengths in the near-millimeter wavelength region (NMMW — roughly 0.3 to 3 mm) are sufficiently small that the conventional microwave fundamental-mode waveguide techniques are difficult to implement and are often of limited effectiveness. Quasi-optical components are frequently employed to overcome these difficulties. Free-standing planar one-dimensional wire grids show promise, based on their strong polarizing properties, in the fabrication of many such components. In this paper we discuss a straight-forward method of fabrication of one-dimensional wire grids that has been employed on a normal machine shop lathe to produce grids of sufficient quality for many NMMW applications. Examination of their mechanical quality and NMMW performance is also presented.

Since urine culture and urinalysis are both of uncertain reliability in diagnosing symptomatic urinary tract infections in patients with chronic urinary catheters, we performed sequential quantitative cultures and urinalyses on 177 urine specimens from 14 patients with long-term urinary catheters during a 12-month period. We found high concentrations of greater than or equal to 2 species of aerobic bacteria or fungi in most specimens examined. Pyuria was common even during asymptomatic periods; hematuria was less common. During symptomatic urinary tract infections, neither urinalyses nor quantitative urine cultures exhibited changes specific for such infections. Thus neither urinalysis nor urine culture appears to be a reliable test for symptomatic urinary tract infections in patients with chronic urinary catheters.

The utility of unstable-resonator (UR) laser cavities has been amply demonstrated with visible and infrared lasers. Extensive analysis of their performance and characteristics has been conducted at these wavelengths. However, in the near-millimeter wave region (NMMW - roughly 0.3 to 3 mm) relatively little has been done [1, 2, 3]. Nevertheless their ability to provide compact dimensions, excellent energy conversion, and good mode control has been demonstrated. This paper presents additional results dealing primarily with C12H 3 F at 605 GHz and C13H 3 F at 246 GHz, but also with performance with other gaseous gain media.

Self-pumping has been observed in a cerium-doped Ba(2-x)Sr(x)K(1-y)Na(y)Nb(5)O(15) (BSKNN) crystal at four argonion laser wavelengths. Phase-conjugate reflectivities as high as 30% were measured with response times inversely proportional to the 0.5 power of the input intensity. The response time for beam fanning in the crystal was determined to be inversely proportional to the 0.82 power of the input intensity.

Self-pumped phase conjugation has been observed at selected laser wavelengths over the range 647–780 nm. Phase-conjugate reflectivities as great as 20% were measured for power levels ranging from 2 to 100 mW. In addition, phase-conjugate and beam-fanning response times were also measured. Our observations were carried out in crystals belonging to the tungsten-bronze family; these crystals were doped with cerium at the 9-fold coordinated lattice sites to give a red photorefractive response.