Si-prism-array coupled terahertz-wave parametric oscillator with pump light totally reflected at the terahertz-wave...

Area of Science:

• Optics and Photonics
• Terahertz (THz) Spectroscopy
• Nonlinear Optics

Background:

• Terahertz (THz)-wave parametric oscillators (TPOs) are crucial for generating tunable THz radiation.
• Optimizing pump-wave coupling and minimizing losses are key challenges in TPO design.
• Existing Si-prism-coupled TPOs (Si-TPOs) face limitations in output energy and frequency tuning range.

Purpose of the Study:

• To demonstrate a novel Si-prism-array coupled THz-wave parametric oscillator with total pump reflection (PR-Si-TPO).
• To investigate the impact of an air gap on pump reflection and THz-wave coupling efficiency.
• To compare the performance of the PR-Si-TPO with a conventional Si-TPO.

Main Methods:

• Fabrication of a PR-Si-TPO incorporating an 800 nm air gap between the crystal and Si-prism array.
• Utilizing total internal reflection of the pump wave at the THz-wave exit surface.
• Characterizing THz-wave output energy, oscillating threshold, and frequency tuning range.

Main Results:

• The air gap effectively eliminates pump reflection losses and ensures efficient THz-wave coupling.
• Compared to Si-TPO, the PR-Si-TPO exhibits a 20-50 times enhancement in THz-wave output energy for frequencies between 1.8-2.3 THz.
• The oscillating threshold for the PR-Si-TPO is reduced by 10%-35%.
• The PR-Si-TPO's frequency tuning range is extended to 3.66 THz, significantly higher than the 2.5 THz of the Si-TPO.

Conclusions:

• The PR-Si-TPO design significantly improves THz-wave generation efficiency and tunability.
• The strategic use of an air gap is critical for optimizing pump coupling and overall device performance.
• This advancement offers a more powerful and versatile source for THz applications.