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A type of single sideband electrooptic modulator with the active electrooptic crystal surrounded by a ferrite tuning element and placed inside a square waveguide is described. Frequency tunability as a function of waveguide dimension and the choice of modulation frequency and optical wavelength are presented. >

Earlier measurements of absolute frequencies of 12C16O laser lines by heterodyning with second harmonics of a 12C16O2 laser have been extended to 15 more lines by use of the rare isotopes 12C18O2 and 13C16O2. Interband difference frequencies for 20 pairs of 12C16O lines have also been measured by beat frequency techniques. These data together with 1438 other previously reported frequency measurements in the microwave and infrared regions have been analyzed to determine coefficients of a Dunham series E vJ = Σ m,n Y mn (v + 1 2 ) m [J(J + 1)] n for the CO electronic ground state. Transition frequencies predicted from the derived coefficients are substantially more accurate than earlier tabulations, having estimated uncertainties of the order of 2 MHz in the strongest laser bands. The coefficient Y31 has been determined for the first time.

The absorption line parameters including self- and nitrogen-broadening coefficients of 17 H 2 O lines in the 10- to 15-μm spectral region have been measured using tunable diode laser techniques. Many of the H 2 O lines are pure rotational lines, and their line-widths exhibit the expected general narrowing trend as the rotational quantum number increases.

Difference frequencies between rare isotope CO lasers and a 12 C 16 O laser have been measured by optical heterodyne techniques. These data for 12 C 18 O, 13 C 16 O, and 13 C 18 O have been used together with the 15 previously reported Dunham coefficients Y kl for 12 C 16 O to determine a set of mass independent parameters Δ kl and U kl defined by Y kl = μ -( k /2+ l )[1+ m e (Δ C kl / M C + Δ O kl / M O )] U kl . The 01, 1 0, and 20 correction terms were found to be statistically significant. Line frequencies calculated from the resulting 15 Dunham coefficients for the rare isotopes are accurate to a few MHz in the measured laser bands.

The self-broadened and nitrogen-broadened absorption profiles of the Q -branch head of the 10 0 0 ← 01 1 0 band of CO 2 near 618 cm −1 were studied under high resolution (∼10 −4 cm −1 ) using tunable diode laser techniques. The intensity and linewidth of several lines in this Q branch, the ν 2 band, 10.4-μm and 9.4-μm laser bands have been measured accurately. The lineshape of a CO 2 line has also been measured to be Lorentzian within experimental accuracy to about 15 half-widths. Preliminary calculated Q -branch head absorption profiles agree reasonably well with the observed profiles.

The hyperfine spectra of the (17-7) P (57) line of 79 Br 2 and the (12-4) P (129) line of 81 Br 2 , both of the B 3 Π 0 + u ← X 1 Σ g + electronic transition near 633 nm have been measured by the saturated absorption method. An analysis based on nuclear quadrupole and spin-rotation interactions is presented.

Tunable diode laser measurements of water vapour lines in the 5 μm region have been extended to include oxygen as well as nitrogen broadening. Positive pressure shifts of line positions have been observed for the first time in the v 2 band. Absolute calibration of a line position using the CO laser as a reference has also been carried out.

Water vapor line and continuum absorption in the 900 to 1050 cm −1 region were measured with a diode laser spectrometer and a heatable 100 m White cell. High resolution scans show that the continuum absorption coefficient is proportional to the pressure squared and exponentially to the negative of the absolute temperature. In the vicinity of strong water vapor lines, the observed profile shows a Lorentzian shape and a smooth continuum.

Deflection-modulation displays reveal two mechanisms which contribute to the uniqueness of the CRT display: scan line intensification and line number density. These mechanisms provide significant display characteristics for abrupt feature changes which are orthogonal to scan direction. Equation (1) describes line density variations as a function of line number and horizontal position.