UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

Guest
2024-11-23 18:25
 HOME     CONFERENCES     SEARCH            LOGIN     NEW USER     IMAGES   


Conference: Bucharest University Faculty of Physics 2016 Meeting


Section: Optics, Spectroscopy, Plasma and Lasers


Title:
Setup for the characterization of quantum cascade lasers


Authors:
Laura MIHAI(1), P. BLEOTU(2), D. SPOREA(1)


Affiliation:
1)National Institute for Laser, Plasma and Radiation Physics

Magurele, Romania

2)“Politehnica”University, Bucharest, Romania



E-mail
laura.mihai@inflpr.ro


Keywords:
QCL, quantum cascade laser, standoff spectroscopy


Abstract:
It is almost twenty years that a new class of semiconductor lasers enters the scene through the development of lasers emitting in the mid and far IR spectral region. This achievement constitute a huge leap forward as it concerns the portability of spectroscopic instrumentation operating within the spectral band from 3 μm to 12 μm, as they started, through continuous innovative research, to operate at room temperature. Presently, quantum cascade lasers (QCL) are included in equipments for pollution control, environmental monitoring, advanced spectroscopy, and chemical imaging. They can be used in standoff measurements (6-12 m apart from the target) or as a replacement for Fourier transform IR (FTIR) spectrometers in “finger detection” applications. Within this context, we develop a laboratory setup able to evaluate QCLs characteristics for both fixed wavelength and tunable devices. In the case of fixed wavelength components their performances can be assessed for various operating currents and case temperature. The setup makes possible the measurement of laser power/ energy, wavelength, emitted spectrum, and beam profile, for the wavelength range from 2 μm to 12 μm. For the wavelength and spectral measurements we used an optical spectrum analyzer 721B from Bristol, having a spectral accuracy of ±1ppm. The quality of the beam was evaluated at different distances using a beam profile camera Pyrocam III from Spiricon, having an array of 124x124 pixels and a spatial resolution of 100 μm. Also we determined the dependence of QCL output optical power on wavelength variation. From QCL characterization we noticed that using the proper focusing optics we can obtain a single mode beam of more than 100 mW with a beam diameter of less than 300 µm that can be used for standoff applications such as explosives detection or pollution.


References:

1. J. Faist, F. Capasso, D. L. Sivco, C. Sirtori, A. L. Hutchinson, and A. Y. Cho, Quantum Cascade Laser, Science, 264 (5158), pp. 553–556, (1994), doi:10.1126/science.264.5158.553.

2. www.alpeslasers.ch.

3. www.cascade-technologies.com.

4. www.daylightsolutions.com.

5. www.pranalytica.com/index.php.

6. www.hamamatsu.com/jp/en/product/category/1001/1006/index.html.

7. M. E. Webber, M. B. Pushkarsky and C. K. N. Patel, Ultra-sensitive gas detection using diode lasers and resonant photoacoustic spectroscopy, in Diode Lasers and Applications in Atmospheric Sensing, A. Fried, Ed., Proceedings of SPIE, 4817, pp. 111—122 (2002).

8. P. Kotidis, QCLs enable applications in IR spectroscopy, Laser Focus World, January 2013.

9. R. F. Curl et al., Quantum cascade lasers in chemical physics, Chemical Physics Letters, 487, pp. 1–18 (2010).

Acknowledgement:
The authors acknowledge the financial support of the Romanian Space Agency, under grant 67/2013. The procurement of the tested QCLs and Bristol instrument was financially supported by UEFISCDI, grant 8PM/2010.