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Spectrally resolved far-fields of terahertz quantum cascade lasers
Optics Express
|November 10, 2016
Summary
We developed a fast method to measure terahertz quantum cascade laser far-fields using FTIR spectroscopy. This technique distinguishes laser modes and aids in developing future terahertz sensing applications.
Area of Science:
- Optics and Photonics
- Semiconductor Lasers
- Terahertz Technology
Background:
- Terahertz quantum cascade lasers (TQCLs) are crucial for emerging sensing applications.
- Understanding the emission properties of multimode TQCLs is essential for device optimization.
- Characterizing far-field emission patterns is key to analyzing laser modes.
Purpose of the Study:
- To present a convenient and rapid method for measuring spectrally resolved far-fields of multimode TQCLs.
- To distinguish between different lateral modes (e.g., TM0 and TM1) in Fabry-Pérot cavities.
- To analyze the mode contributions in multimode random laser cavities.
Main Methods:
- Combining a microbolometer focal plane array with Fourier-transform infrared (FTIR) spectroscopy.
- Utilizing 3D finite-element simulations for comparison with experimental results.
- Investigating multimode random laser cavities to understand individual mode contributions.
Main Results:
- Successfully distinguished the far-fields of fundamental TM0 and higher lateral order TM1 modes.
- Experimental results showed excellent agreement with 3D finite-element simulations.
- Analyzed the spectral contribution of individual laser modes within random laser cavities.
Conclusions:
- The developed FTIR-based method provides in-depth knowledge of multimode TQCL emission.
- This technique is valuable for characterizing complex laser cavities at terahertz frequencies.
- The findings support the advancement of TQCLs for future sensing applications.
