Stark effects in optically pumped CH(3)OH far infrared laser

Area of Science:

• Quantum Electronics
• Molecular Spectroscopy
• Laser Physics

Background:

• Far-infrared (FIR) lasers, such as the 118.8-micrometer (µm) methanol (CH3OH) line, are crucial tools in spectroscopy.
• The P(36) 9.4-µm carbon dioxide (CO2) laser is a common pump source for generating FIR laser emissions.
• Understanding Stark tuning effects is essential for controlling and enhancing FIR laser properties.

Purpose of the Study:

• To investigate the Stark tuning properties of the 118.8-µm CH3OH FIR laser line.
• To analyze the impact of Stark fields on the absorption and emission characteristics of the CH3OH laser system.
• To develop a theoretical model for predicting Stark tuning effects in FIR lasers.

Main Methods:

• A rate equation approach was employed to derive a theoretical laser model.
• Experimental measurements were conducted to observe Stark tuning effects.
• Varying Stark electric fields were applied to the CH3OH medium.

Main Results:

• Observed Stark tuning effects include frequency shifting of the CH3OH absorption line and the FIR laser line, as well as amplitude modulation of the FIR output.
• Stark enhancement of the 118.8-µm FIR laser line by a factor of 3 was achieved with a Stark field of 180 V/cm due to frequency shifting of the CH3OH absorption line.
• A frequency shift of approximately 7 MHz in the 118.8-µm FIR laser line was measured with a Stark field of 362 V/cm.

Conclusions:

• Stark tuning provides an effective method for enhancing the output power of the 118.8-µm CH3OH FIR laser.
• The observed amplitude modulation characteristics are consistent with Stark absorption modulation.
• The study demonstrates the potential for precise control of FIR laser parameters through the application of Stark fields.