Measurement of the Pure Rotational Quasibound Spectrum ofHeH+in a Laboratory Plasma by Direct Laser Absorption

1997 ◽  
Vol 79 (15) ◽  
pp. 2779-2782 ◽  
Author(s):  
Zhuan Liu ◽  
Paul B. Davies
Keyword(s):  
Laboratory Plasma ◽  
Laser Absorption ◽  
Direct Laser

scholarly journals Integrated IR Modulator with a Quantum Cascade Laser

2021 ◽  
Vol 11 (14) ◽  
pp. 6457
Author(s):  
Janusz Mikołajczyk ◽  
Dariusz Szabra
Keyword(s):  
Quantum Cascade Laser ◽  
Quantum Cascade Lasers ◽  
Model Simulation ◽  
Numerical Models ◽  
Spectral Characteristics ◽  
Electrical Performance ◽  
Laboratory Model ◽  
Quantum Cascade ◽  
Laser Absorption ◽  
Direct Laser

This paper presents an infrared pulsed modulator into which quantum cascade lasers and a current driver are integrated. The main goal of this study was to determine the capabilities of a new modulator design based on the results of its electrical model simulation and laboratory experiments. A simulation model is a unique tool because it includes the electrical performance of the lasing structure, signal wiring, and driving unit. In the laboratory model, a lasing structure was mounted on the interfacing poles as close to the switching electronics as possible with direct wire bonding. The radiation pulses and laser biasing voltage were registered to analyze the influence of laser module impedance. Both simulation and experimental results demonstrated that the quantum cascade laser (QC laser) design strongly influenced the shape of light, driving current, and biasing voltage pulses. It is a complex phenomenon depending on the laser construction and many other factors, e.g., the amplitude and time parameters of the supplying current pulses. However, this work presents important data to develop or modify numerical models describing QC laser operation. The integrated modulator provided pulses with a 20–100 ns duration and a frequency of 1 MHz without any active cooling. The designed modulator ensured the construction of a sensor based on direct laser absorption spectroscopy, applying the QC laser with spectral characteristics matched to absorption lines of the detected substances. It can also be used in optical ranging and recognition systems.

Cu-Direct Via-Hole Drilling of Aramid Fiber Reinforced Build-Up Layer by CO2 Laser Beam

2005 ◽  
Author(s):  
Eiichi Aoyama ◽  
Toshiki Hirogaki ◽  
Keiji Ogawa ◽  
Nobuyuki Doi ◽  
Ryu Minagi
Keyword(s):  
Co2 Laser ◽  
Copper Foil ◽  
Effective Means ◽  
Hole Diameter ◽  
Hole Drilling ◽  
Printed Wiring Boards ◽  
Laser Absorption ◽  
Direct Laser ◽  
Via Hole ◽  
The Difference

This report describes the features of Cu-direct laser drilled hole quality on multi-layer Printed Wiring Boards (PWBs). Cu-direct laser drilling drills the outer copper foil and build-up layer at the same time, which makes it difficult to form a blind via hole (BVH) with high quality because the copper foil has high reflection coefficient for a CO2 laser with wavelength 10.6 μm. Therefore, this study focused on improving drilled hole qualities such as diameter and overhang. First, the influence of laser irradiation conditions on forming BVH and the drilled hole diameter were investigated in detail. Second, a new method employing thermography was proposed in order to evaluate the absorption of copper foil after surface treatment. Third, the effect of mixing fillers into the build-up layer in order to reduce the amount of overhang was shown to be effective both experimentally and theoretically. As a result, it is clear that decreasing the difference in the laser absorption rate of the outer copper foil is an effective means to control the hole diameter and reducing the heat characteristic difference between the outer copper foil and the build-up layer can effectively decrease overhang.

Infrared diode laser spectroscopy

2010 ◽  
Vol 18 (4) ◽  
Author(s):  
S. Civiš ◽  
J. Cihelka ◽  
I. Matulková
Keyword(s):  
Fourier Transform ◽  
Detection Limit ◽  
Diode Laser ◽  
Molecular Ions ◽  
Emission Region ◽  
Cavity Surface ◽  
Interstellar Space ◽  
Photoacoustic Detection ◽  
Laser Absorption ◽  
Direct Laser

AbstractThree types of lasers (double-heterostructure 66 K InAsSb/InAsSbP laser diode, room temperature, multi quantum wells with distributed feedback (MQW with DFB) (GaInAsSb/AlGaAsSb based) diode laser and vertical cavity surface emitting lasers (VCSELs) (GaSb based) have been characterized using Fourier transform emission spectroscopy and compared. The photoacoustic technique was employed to determine the detection limit of formaldehyde (less than 1 ppmV) for the strongest absorption line of the v3 + v5 band in the emission region of the GaInAsSb/AlGaAsSb diode laser. The detection limit (less than 10 ppbV) of formaldehyde was achieved in the 2820 cm−1 spectral range in case of InAsSb/InAsSbP laser (fundamental bands of v1, v5). Laser sensitive detection (laser absorption together with high resolution Fourier transform infrared technique including direct laser linewidth measurement, infrared photoacoustic detection of neutral molecules (methane, form-aldehyde) is discussed.Additionally, very sensitive laser absorption techniques of such velocity modulation are discussed for case of laser application in laboratory research of molecular ions. Such sensitive techniques (originally developed for lasers) contributed very much in identifying laboratory microwave spectra of a series of anions (C6H−, C4H−, C2H−, CN−) and their discovery in the interstellar space (C6H−, C4H−).

INTRACAVITY LASER ABSORPTION SPECTROSCOPY OF NO2 AND CH4 COOLED IN A SLIT JET SUPERSONIC EXPANSION

1991 ◽  
Vol 01 (C7) ◽  
pp. C7-471-C7-476
Author(s):  
A. CAMPARGUE ◽  
M. CHENEVIER ◽  
A. DELON ◽  
R. JOST ◽  
F. STOECKEL
Keyword(s):  
Absorption Spectroscopy ◽  
Laser Absorption Spectroscopy ◽  
Supersonic Expansion ◽  
Laser Absorption ◽  
Intracavity Laser
Sign in / Sign up

Export Citation Format

Share Document