Sample interview questions: What are some common techniques for achieving tunable laser output in the terahertz range?
Sample answer:
- Quantum Cascade Lasers (QCLs):
- Utilize multiple quantum wells to achieve tunable terahertz output through adjustments in the structure and composition of the wells.
- Provide continuous tuning over a wide range of frequencies, typically from 1 THz to several THz.
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Offer compact and efficient laser sources with high output power.
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Tunable Terahertz Metamaterials:
- Employ engineered structures composed of periodic or aperiodic elements to manipulate terahertz waves.
- Allow for dynamic control of the effective permittivity and permeability, leading to tunable terahertz properties.
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Can achieve tunable resonant frequencies, enabling narrowband terahertz emission.
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Optical Parametric Amplifiers (OPAs):
- Utilize nonlinear crystals to generate tunable terahertz radiation through parametric amplification of a pump laser.
- Offer broad tunability, extending from the mid-infrared to the terahertz range.
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Provide high spectral purity and low noise operation.
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Free-Electron Lasers (FELs):
- Utilize an electron beam interacting with a periodic magnetic field to generate coherent terahertz radiation.
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