Semiconductor superlattices: a tool for terahertz acoustics.

Area of Science:

• Solid-state physics
• Materials science
• Acoustics

Background:

• Optical to acoustic transduction in semiconductor superlattices is studied for sub-terahertz frequencies.
• Acoustic modes are excited by femtosecond laser pulses, with frequencies linked to superlattice periodicity.

Purpose of the Study:

• To explore semiconductor superlattices as quasi-monochromatic acoustic wave generators.
• To investigate superlattices as sensitive and selective acoustic wave detectors.
• To present experimental results on the generation, propagation, and detection of high-frequency acoustic waves up to 1 THz.

Main Methods:

• Femtosecond laser pulses used to excite acoustic modes in semiconductor superlattices.
• Picosecond ultrasonics experiments in transmission geometry.
• Analysis of acoustic wave generation, propagation, and detection.

Main Results:

• Demonstrated excitation of acoustic modes with frequencies related to superlattice structure.
• Showcased extraction and propagation of acoustic waves into the substrate.
• Achieved generation and detection of acoustic waves up to 1 THz.

Conclusions:

• Semiconductor superlattices function as effective quasi-monochromatic acoustic generators.
• Superlattices exhibit high sensitivity and selectivity as acoustic detectors.
• The study validates the use of superlattices for high-frequency (up to 1 THz) acoustic wave applications.