Balancing the Number of Quantum Wells in HgCdTe/CdHgTe Heterostructures for Mid-Infrared Lasing

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• HgCdTe-based heterostructures with quantum wells (QWs) are key for semiconductor lasers operating in the 3-5 μm atmospheric transparency window.
• The no-parabolic law of carrier dispersion in these structures offers a method to suppress Auger recombination, a critical factor in laser efficiency.

Purpose of the Study:

• To analyze the stimulated emission (SE) thresholds in HgCdTe heterostructures with varying numbers of QWs under optical pumping.
• To determine the impact of QW count on modal gain, threshold pumping intensity, and the operating temperature of SE.

Main Methods:

• Optical pumping of HgCdTe heterostructures with different numbers of QWs in the active region.
• Analysis of stimulated emission (SE) thresholds to deduce total losses within the structures.
• Comparison of threshold pumping intensities across structures with varying QW counts.

Main Results:

• A higher number of QWs leads to increased modal gain, resulting in a lower threshold pumping intensity required for SE.
• Increased modal gain directly correlates with a higher operating temperature for SE.
• Beyond a certain QW count, the threshold intensity becomes independent of the number of QWs, determined solely by the transparency concentration of a single QW.

Conclusions:

• Enhancing modal gain through a higher QW count offers a viable strategy to moderately increase the SE temperature in mid-infrared HgCdTe-based heterostructures.
• The study provides critical insights into optimizing HgCdTe heterostructures for efficient mid-infrared laser applications.