Noninvasive measurement of cerebral venous oxygenation in neonates with a multi-wavelength, fiber-coupled laser diode optoacoustic system

2018 ◽  
Author(s):  
Rinat O. Esenaliev ◽  
Stephen Herrmann ◽  
Irene Y. Petrov ◽  
Yuriy Petrov ◽  
Rafael Fonseca ◽  
...  
Keyword(s):  
Laser Diode ◽  
Noninvasive Measurement ◽  
Multi Wavelength

scholarly journals Two-wavelength thermal–optical determination of light-absorbing carbon in atmospheric aerosols

2019 ◽  
Vol 12 (6) ◽  
pp. 3173-3182 ◽  
Author(s):  
Dario Massabò ◽  
Alessandro Altomari ◽  
Virginia Vernocchi ◽  
Paolo Prati
Keyword(s):  
Laser Diode ◽  
Atmospheric Aerosols ◽  
Direct Determination ◽  
Optical Transmittance ◽  
Carbonaceous Aerosol ◽  
Electromagnetic Spectrum ◽  
Multi Wavelength ◽  
Physics Department ◽  
The University

Abstract. Thermal–optical analysis is widely adopted for the quantitative determination of total (TC), organic (OC), and elemental (EC) carbon in atmospheric aerosol sampled by suitable filters. Nevertheless, the methodology suffers from several uncertainties and artifacts such as the well-known issue of charring affecting the OC–EC separation. In the standard approach, the effect of the possible presence of brown carbon, BrC, in the sample is neglected. BrC is a fraction of OC, usually produced by biomass burning with a thermic behavior intermediate between OC and EC. BrC is optically active: it shows an increasing absorbance when the wavelength moves to the blue–UV region of the electromagnetic spectrum. Definitively, the thermal–optical characterization of carbonaceous aerosol should be reconsidered to address the possible BrC content in the sample under analysis. We introduce here a modified Sunset Lab Inc. EC–OC analyzer. Starting from a standard commercial instrument, the unit has been modified at the physics department of the University of Genoa (Italy), making possible the alternative use of the standard laser diode at λ=635 nm and of a new laser diode at λ=405 nm. In this way, the optical transmittance through the sample can be monitored at both wavelengths. Since at shorter wavelengths the BrC absorbance is higher, a better sensitivity to this species is gained. The modified instrument also gives the possibility to quantify the BrC concentration in the sample at both wavelengths. The new unit has been thoroughly tested, with both artificial and real-world aerosol samples: the first experiment, in conjunction with the multi-wavelength absorbance analyzer (MWAA; Massabò et al., 2013, 2015), resulted in the first direct determination of the BrC mass absorption coefficient (MAC) at λ=405 nm: MAC =23±1 m2 g−1.

A Single to Multi-Wavelength Converter Using Fabry–Perot Laser Diode with Linear Optical Amplifier

2004 ◽  
Vol 43 (9A) ◽  
pp. 6125-6128
Author(s):  
Jeung-Mo Kang ◽  
Yong Ook Kim ◽  
Sang-Kook Han ◽  
Seok Lee
Keyword(s):  
Laser Diode ◽  
Optical Amplifier ◽  
Wavelength Converter ◽  
Fabry Perot ◽  
Multi Wavelength ◽  
Linear Optical

scholarly journals Research on spectral peaks thermal-drifting in multi-wavelength infrared laser diode

2014 ◽  
Vol 63 (15) ◽  
pp. 154206
Author(s):  
Xue Ming-Xi ◽  
Chen Zhi-Bin ◽  
Wang Wei-Ming ◽  
Ouyang Hui-Quan ◽  
Liu Xian-Hong ◽  
...  
Keyword(s):  
Laser Diode ◽  
Infrared Laser ◽  
Spectral Peaks ◽  
Multi Wavelength

Generation of tunable multi-wavelength optical short pulses using self-seeded Fabry-Perot laser diode and tilted multimode fiber Bragg grating

2011 ◽  
Vol 9 (4) ◽  
pp. 041403-41406
Author(s):  
蔡同健 Tongjian Cai ◽  
刘云启 Yunqi Liu ◽  
张小贝 Xiaobei Zhang ◽  
王廷云 Tingyun Wang
Keyword(s):  
Fiber Bragg Grating ◽  
Laser Diode ◽  
Bragg Grating ◽  
Multimode Fiber ◽  
Short Pulses ◽  
Fabry Perot ◽  
Multi Wavelength
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