Sample interview questions: What are some common techniques for achieving tunable laser output in the infrared range?
Sample answer:
- Cryogenically-Cooled Semiconductor Diodes:
- Utilize compound semiconductors, such as indium antimonide (InSb) and lead-tin selenide (PbSnSe), which exhibit tunability at cryogenic temperatures.
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Applicable for mid-infrared and far-infrared ranges.
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Quantum Cascade Lasers (QCLs):
- Employ intersubband transitions in semiconductor structures to achieve tunability.
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Capable of continuous-wave operation and high power output in the mid-infrared to terahertz range.
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Optical Parametric Oscillators (OPOs):
- Nonlinear optical devices that generate tunable laser output through parametric amplification of a pump beam.
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Broad tunability range, extending from the visible to the mid-infrared and beyond.
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Free-Electron Lasers (FELs):
- Utilize the interaction of a relativistic electron beam with a periodic magnetic field to generate tunable laser radiation.
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Capable of achieving very high power and tunability across a wide spectral range, including the infrared.
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Tunable Solid-State Lasers:
- Involve the use of solid-state gain media, such as doped crystals or semiconductors, with tunable optical properties.
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