Design of a ZnMnSe∕ZnMgSe spin-polarized terahertz quantum cascade laser tunable by magnetic field

2006 ◽  
Vol 89 (1) ◽  
pp. 011109 ◽  
Author(s):  
Ivana Savić ◽  
Zoran Ikonić ◽  
Nenad Vukmirović ◽  
Dragan Indjin ◽  
Paul Harrison ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Cascade Laser ◽  
Quantum Cascade ◽  
Spin Polarized

scholarly journals Quantum cascade laser: Applications in chemical detection and environmental monitoring

2009 ◽  
Vol 24 (2) ◽  
pp. 75-81 ◽  
Author(s):  
Jelena Radovanovic ◽  
Vitomir Milanovic
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Quantum Cascade Laser ◽  
Optical Gain ◽  
Ambient Air ◽  
Landau Levels ◽  
Fine Tuning ◽  
Structural Parameter ◽  
Laser Applications ◽  
Quantum Cascade

In this paper we consider the structural parameter optimization of the active region of a GaAs-based quantum cascade laser in order to maximize the optical gain of the laser at the characteristic wavelengths, which are best suited for detection of pollutant gasses, such as SO2, HNO3, CH4, and NH3, in the ambient air by means of direct absorption. The procedure relies on applying elaborate tools for global optimization, such as the genetic algorithm. One of the important goals is to extend the applicability of a single active region design to the detection of several compounds absorbing at close wave-lengths, and this is achieved by introducing a strong external magnetic field perpendicularly to the epitaxial layers. The field causes two-dimensional continuous energy subbands to split into the series of discrete Landau levels. Since the arrangement of Landau levels depends strongly on the magnitude of the magnetic field, this enables one to control the population inversion in the active region, and hence the optical gain. Furthermore, strong effects of band non-parabolicity result in subtle changes of the lasing wavelength at magnetic fields which maximize the gain, thus providing a path for fine-tuning of the output radiation properties and changing the target compound for detection. The numerical results are presented for quantum cascade laser structures designed to emit at specified wavelengths in the mid-infrared part of the spectrum.

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