Flat Top Optical Frequency Combs Based on a Single-Core Quantum Cascade Laser at Wavelength of ～ 8.7 μm

作者：Ma, Yu; Li, Wei-Jiang; Xu, Yun-Fei; Liu, Jun-Qi^*; Zhuo, Ning^*; Yang, Ke; Zhang, Jin-Chuan; Zhai, Shen-Qiang; Liu, Shu-Man; Wang, Li-Jun; Liu, Feng-Qi

来源：Chinese Physics Letters, 2023, 40(1): 014201.

DOI：10.1088/0256-307X/40/1/014201

• Comb modes
• Flat-top
• Flat-top spectrum
• Gain medium
• Homogeneous gain
• Optical frequency combs
• Optical power
• Optical-frequency combs
• Output power
• Spectral emission

We present optical frequency combs with a spectral emission of 48 cm(-1) and an output power of 420 mW based on a single-core quantum cascade laser at lambda similar to 8.7 mu m. A flat top spectrum sustains up to 130 comb modes delivering similar to 3.2 mW of optical power per mode, making it a valuable tool for dual comb spectroscopy. The homogeneous gain medium, relying on a slightly diagonal bound-to-continuum structure, promises to provide a broad and stable gain for comb operating. Remarkably, the dispersion of this device is measured within 300 fs(2)/mm to ensure stable comb operation over 90% of the total current range. The comb is observed with a narrow beatnote linewidth around 2 kHz and has weak dependence on the applied current for stable comb operation.

• 单位
  中国科学院; 中国科学院大学