Tunable multi-cycle THz generation in organic crystal HMQ-TMS

Area of Science:

• Nonlinear optics
• Terahertz (THz) science and technology
• Organic crystal applications

Background:

• Terahertz (THz) pulse generation is crucial for spectroscopy and imaging.
• Organic nonlinear crystals offer potential advantages over inorganic materials.
• Controlling THz pulse properties like frequency and energy is an ongoing challenge.

Purpose of the Study:

• To demonstrate tunable THz pulse generation using the organic crystal HMQ-TMS.
• To investigate the suppression of harmonic frequencies during THz generation.
• To compare the performance of HMQ-TMS with established inorganic THz generators.

Main Methods:

• Collinearly phase-matched optical rectification of temporally shaped 800 nm laser pulses.
• Utilizing the organic nonlinear crystal HMQ-TMS [2-(4-hydroxy-3-methoxystyryl)-1-methylquinolinium 2,-4,-6-trimethylbenzenesulfonate].
• Varying the crystal thickness to selectively suppress harmonic frequency components.

Main Results:

• Continuous tunability of THz pulses from 0.3 to 0.8 THz achieved.
• Up to 20 times higher THz pulse energies generated compared to Zinc Telluride (ZnTe).
• THz energy conversion efficiencies on the order of 10(-5) were measured.

Conclusions:

• HMQ-TMS is a highly efficient organic crystal for generating tunable THz pulses.
• The method allows for selective suppression of unwanted harmonic frequencies.
• This work presents a promising alternative for high-energy THz pulse generation.