A compact, continuous-wave terahertz source based on a quantum-cascade laser and a miniature cryocooler.

Area of Science:

• Physics
• Engineering
• Spectroscopy

Background:

• Terahertz (THz) radiation sources are crucial for various scientific and technological applications.
• Compact and user-friendly THz systems are needed to enhance accessibility and portability.
• Existing THz sources often face limitations in terms of size, power consumption, or ease of use.

Purpose of the Study:

• To develop a compact and user-friendly terahertz radiation source.
• To integrate a quantum-cascade laser (QCL) with a low-input-power Stirling cooler.
• To demonstrate the system's applicability in imaging and molecular spectroscopy.

Main Methods:

• Development of a two-miniband quantum-cascade laser (QCL) optimized for high output and low electrical power.
• Integration of the QCL with a compact Stirling cooler (7 W cooling capacity at 65 K).
• Ensuring efficient thermal coupling between the QCL and the cooler's cold finger.

Main Results:

• A complete terahertz radiation system weighing less than 15 kg was realized.
• The system operates at 3.1 THz with a maximum output power of 8 mW.
• The terahertz emission profile was shaped to be a fundamental Gaussian beam.
• Successful demonstration in terahertz imaging and molecular spectroscopy experiments.

Conclusions:

• The developed system represents a significant advancement in compact and accessible terahertz radiation sources.
• The combination of a high-performance QCL and an efficient Stirling cooler offers a practical solution for various THz applications.
• The system's performance and demonstrated applicability pave the way for broader adoption in scientific research and industrial use.