13CO 2 /12CO 2 ratio analysis in exhaled air by lead-salt tunable diode lasers for noninvasive diagnostics in gastroenterology

1999 ◽  
Author(s):  
Eugene V. Stepanov ◽  
Pavel V. Zyrianov ◽  
Valerii A. Miliaev ◽  
Yurii G. Selivanov ◽  
Eugene G. Chizhevskii ◽  
...  
Keyword(s):  
Diode Lasers ◽  
Lead Salt ◽  
Ratio Analysis ◽  
Noninvasive Diagnostics ◽  
Tunable Diode Lasers ◽  
Exhaled Air

Heterolayer lead-salt diode lasers

1987 ◽  
Vol 65 (8) ◽  
pp. 999-1002
Author(s):  
Yonfeng Yang ◽  
B. K. Garside ◽  
P. E. Jessop
Keyword(s):  
Diode Lasers ◽  
Threshold Current ◽  
Lead Salt ◽  
Tunable Diode Lasers ◽  
Low Threshold ◽  
Current Densities ◽  
Dopant Atoms ◽  
Doping Profiles ◽  
Lattice Matched ◽  
Probe Measurements

Hot-wall epitaxy (HWE) has been used to grow heterostructure lead-salt materials from which low-threshold tunable diode lasers have been made. A new HWE structure consisting of a Pb(Se, Te) layer sandwiched between two lattice-matched (Pb, Sn)Te layers has resulted in lasers of good electrical and material quality, and threshold current densities as low as 200 A∙cm−2 (at 40 K). This occurred even though this structure is expected to be nonconfining to both light and electrical carriers. This result is due to the very rapid interdiffusion of dopant atoms between the epilayers during the growth process. Dopant interdiffusion has been investigated using an etch-back technique combined with hot-point probe measurements to observe changes in the doping profiles of the structures. Very large values for the diffusion constants of dopants have been deduced from these measurements: 2.3 × 10−15 and 1.1 × 10−15 cm2∙s−1 for Bi and Tl, respectively.

Search for narrow-band-noise modulations of the infrared transmission of blue bronze

2002 ◽  
Vol 12 (9) ◽  
pp. 85-86
Author(s):  
R. C. Rai ◽  
V. A. Bondarenko ◽  
J. W. Brill
Keyword(s):  
Absorption Coefficient ◽  
Narrow Band ◽  
Diode Lasers ◽  
Infrared Transmission ◽  
Narrow Band Noise ◽  
Band Noise ◽  
Tunable Diode Lasers ◽  
Upper Limits ◽  
Blue Bronze

We have searched for narrow-band-noise (NBN) modulations of the infrared transmission in blue bronze, using tunable diode lasers. No modulations were observed, giving an upper limits for NBN changes in the absorption coefficient of $\Delta \alpha_{NBN} < 0.3 $ / cm ($\approx \alpha/2000$). The implication of these results on proposed CDW properties and NBN mechanisms are discussed.

Chemical Analysis of Gases with Tunable Diode Lasers

1994 ◽  
Author(s):  
Joseph Bechara ◽  
David R. Karecki ◽  
Gervase I. Mackay ◽  
Harold I. Schiff ◽  
Shachar (Don) Nadler
Keyword(s):  
Chemical Analysis ◽  
Diode Lasers ◽  
Tunable Diode Lasers
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