Absorption bands of O2 and OH in a new ultraviolet continuum and in the XeCl laser spectrum

1984 ◽  
Vol 62 (12) ◽  
pp. 1403-1413 ◽  
Author(s):  
M. Shimauchi ◽  
K. Oikawa
Keyword(s):  
Discharge Chamber ◽  
Xecl Laser ◽  
Ultraviolet Continuum ◽  
Absorption Bands ◽  
Third Order ◽  
Laser Spectrum ◽  
Light Pulses ◽  
Vibrational Levels ◽  
Quartz Spectrograph ◽  
The Continuum

Two excimer lasers of the automatic pre-ionization type have been constructed. To avoid impurities, the two series of condensers were placed outside the discharge chamber. Using one of these devices we have observed a new ultraviolet (UV) continuum from a discharge through a He–O2 mixture at 900 Torr. The continuous nature of this emission was assured by the observation of almost 80 absorption bands of the O2 Schumann-Runge system arising from highly excited vibrational levels and of some OH bands in the A–X system. The same type of discharge through pure He emits no continuum but some OH bands. The time dependence of the light pulses was studied to infer the origin of the continuum. Based on these observations, we show that the strong absorption in the B–X, 0–2 band of the XeCl laser is due to the P11, Q13, and Q13′ lines in the 0–0 band of the OH A–X system; the estimated intensity of this absorption amounting to 5–7% of the total intensity of the XeCl laser. The XeCl spectra were photographed on an E1 quartz spectrograph and in the third order of a 6.65 m grating.

scholarly journals Highly efficient THz four-wave mixing in doped silicon

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Nils Dessmann ◽  
Nguyen H. Le ◽  
Viktoria Eless ◽  
Steven Chick ◽  
Kamyar Saeedi ◽  
...  
Keyword(s):  
Four Wave Mixing ◽  
Wave Mixing ◽  
Optical Nonlinearities ◽  
Third Order ◽  
Picosecond Pulses ◽  
Light Pulses ◽  
A Value ◽  
Doped Silicon ◽  
Perturbative Regime ◽  
Silicon Doped

AbstractThird-order non-linearities are important because they allow control over light pulses in ubiquitous high-quality centro-symmetric materials like silicon and silica. Degenerate four-wave mixing provides a direct measure of the third-order non-linear sheet susceptibility χ(3)L (where L represents the material thickness) as well as technological possibilities such as optically gated detection and emission of photons. Using picosecond pulses from a free electron laser, we show that silicon doped with P or Bi has a value of χ(3)L in the THz domain that is higher than that reported for any other material in any wavelength band. The immediate implication of our results is the efficient generation of intense coherent THz light via upconversion (also a χ(3) process), and they open the door to exploitation of non-degenerate mixing and optical nonlinearities beyond the perturbative regime.

Vibration-rotation bands and rotational constants of dideuteroacetylene

1955 ◽  
Vol 232 (1190) ◽  
pp. 291-309 ◽  
Keyword(s):  
Resolving Power ◽  
Vibrational States ◽  
Absorption Bands ◽  
Rotational Constants ◽  
Vibrational Assignments ◽  
Vibrational Anharmonicity ◽  
A Value ◽  
Vibrational Levels ◽  
Vibration Rotation ◽  
Very High

Nine vibrational absorption bands of dideutero-acetylene have been examined with very high resolving power. The rotational constants have been determined for the vibrational levels concerned, and the coefficients α i have been determined with more convincing accuracy than previously. In some of the bands the Q branches have been resolved, so that the l -doubling coefficients q i could be derived, and details could be established about the doublet components in some II levels. The results emphasize the need of high resolution if the vibrational assignments are to be unambiguous, and if reliable values of the rotational constants are to be derived. A value of B e has been obtained, and the vibrational anharmonicity coefficients have been considered briefly. Estimates of the centrifugal stretching constants D i in different vibrational states have been made, and one anomalous case has been found.

scholarly journals Variability of the Ultraviolet Continuum and Emission Lines of NGC 3783

1994 ◽  
Vol 159 ◽  
pp. 403-403
Author(s):  
G.A. Reichert
Keyword(s):  
Seyfert Galaxy ◽  
Light Curves ◽  
Emission Lines ◽  
Power Density Spectrum ◽  
Ultraviolet Continuum ◽  
Density Spectrum ◽  
International Ultraviolet Explorer ◽  
Monitoring Effort ◽  
Ngc 5548 ◽  
The Continuum

On behalf of the International AGN Watch, I report on the results of intensive ultraviolet spectral monitoring of the Seyfert 1 galaxy NGC 3783. The nucleus of NGC 3783 was observed with the International Ultraviolet Explorer satellite on a regular basis for a total of seven months, once every 4 days for the first 172 days and once every other day for the final 50 days. Significant variability was observed in both continuum and emission-line fluxes. The light curves for the continuum fluxes exhibited two well-defined local minima or “dips,” the first lasting ≲ 20 days and the second ≲ 4 days, with additional episodes of relatively rapid flickering of approximately the same amplitude. As in the case of NGC 5548 (the only other Seyfert galaxy that has been the subject of such an intensive, sustained monitoring effort), the largest continuum variations were seen at the shortest wavelengths, so that the continuum became “harder” when brighter. The variations in the continuum occurred simultaneously at all wavelengths (Δt < 2 days). Generally, the amplitude of variability of the emission lines was lower than (or comparable to) that of the continuum. Apart from Mg II (which varied little) and N V (which is relatively weak and badly blended with Lyα) the light curves of the emission lines are very similar to the continuum light curves, in each case with a small systematic delay or “lag.” As for NGC 5548, the highest ionization lines seem to respond with shorter lags than the lower ionization lines. The lags found for NGC 3783 are considerably shorter than those obtained for NGC 5548, with values of (formally) ∼ 0 days for He II+O III], and ∼ 4 days for Lyα, and C IV. The data further suggest lags of ∼ 4 days for Si IV+O IV], and 8–30 days for Si III]+C III]. Uncertainties in these quantities are likely to be of order 2–3 days for the stronger features (Lyα, C IV), and 3–4 days for the weaker ones (He II+O III], Si IV+O IV], Si III]+C III]). Mg II lagged the 1460 Å continuum by ∼ 9 days, although this result depends on the method of measuring the line flux, and may in fact be due to variability of the underlying Fe II lines. Correlation analysis further shows that the power density spectrum contains substantial unresolved power over time scales of ≲ 2 days, and that the character of the continuum variability may change with time.

scholarly journals Spatially separated continuum sources revealed by microlensing in the gravitationally lensed broad absorption line quasar SDSS J081830.46+060138.0

2020 ◽  
Vol 633 ◽  
pp. A101
Author(s):  
D. Hutsemékers ◽  
D. Sluse ◽  
P. Kumar
Keyword(s):  
Absorption Line ◽  
Rest Frame ◽  
Continuum Emission ◽  
Absorption System ◽  
Ultraviolet Continuum ◽  
Broad Absorption ◽  
Extended Source ◽  
Broad Absorption Line ◽  
Onset Velocity ◽  
The Continuum

Gravitational microlensing is a powerful tool for probing the inner structure of distant quasars. In this context, we have obtained spectropolarimetric observations of the two images of the broad absorption line (BAL) quasar SDSS J081830.46+060138.0 (J0818+0601) at redshift z ≃ 2.35. We first show that J0818+0601 is actually gravitationally lensed, and not a binary quasar. A strong absorption system detected at z = 1.0065 ± 0.0002 is possibly due to the lensing galaxy. Microlensing is observed in one image and it magnifies the emission lines, the continuum, and the BALs differently. By disentangling the part of the spectrum that is microlensed from the part that is not microlensed, we unveil two sources of continuum that must be spatially separated: a compact one, which is microlensed, and an extended one, which is not microlensed and contributes to two thirds of the total continuum emission. J0818+0601 is the second BAL quasar in which an extended source of rest-frame ultraviolet continuum is found. We also find that the images are differently polarized, suggesting that the two continua might be differently polarized. Our analysis provides constraints on the BAL flow. In particular, we find that the outflow is seen with a nonzero onset velocity, and stratified according to ionization.

Grating coupling of light pulses into third-order nonlinear waveguides

1991 ◽  
Vol 8 (3) ◽  
pp. 553 ◽  
Author(s):  
Gaetano Assanto ◽  
Manuel B. Marques ◽  
George I. Stegeman
Keyword(s):  
Third Order ◽  
Nonlinear Waveguides ◽  
Light Pulses ◽  
Grating Coupling

scholarly journals SINGLE-DELAY MEASUREMENT OF ULTRASHORT LIGHT PULSES BY THIRD ORDER INTENSITY CORRELATION

1982 ◽  
Vol 31 (2) ◽  
pp. 213
Author(s):  
ZHANG ZHAO-YUAN ◽  
QU LIN-JIE ◽  
LIU CHENG-HUI ◽  
HUO CHONG-RU
Keyword(s):  
Third Order ◽  
Intensity Correlation ◽  
Light Pulses ◽  
Delay Measurement ◽  
Ultrashort Light Pulses
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