Liquid crystal wave plate operating close to 18 THz

Area of Science:

• Optics and Photonics
• Materials Science
• Condensed Matter Physics

Background:

• Controlling mid- and far-infrared (IR) radiation is crucial for novel applications.
• Limited optical elements exist for manipulating IR polarization states.

Purpose of the Study:

• To demonstrate a liquid crystal cell as a phase retarder for mid- and far-IR radiation.
• To explore new tools for IR optics and spectroscopy.

Main Methods:

• A 15-µm thick liquid crystal cell with 8CB (4-octyl-4'-cyanobiphenyl) in the smectic A phase was fabricated.
• The cell's performance was tested using short-pulsed (1 ps) IR radiation at 16.5 µm (18.15 THz) from a free electron laser.

Main Results:

• The liquid crystal cell successfully functioned as a phase retarder (wave plate) for 16.5 µm radiation.
• The experiment utilized a high-repetition-rate (13 MHz) free electron laser.

Conclusions:

• Liquid crystal cells offer a viable method for controlling mid- and far-IR polarization.
• This technology can advance IR metamaterials and multidimensional spectroscopy.