The 70th JSAP Spring Meeting 2023

Presentation information

Oral presentation

3 Optics and Photonics » 3.5 Ultrashort-pulse and high-intensity lasers (formerly 3.6)

[18a-A501-1~6] 3.5 Ultrashort-pulse and high-intensity lasers (formerly 3.6)

Sat. Mar 18, 2023 9:00 AM - 10:45 AM A501 (Building No. 6)

Takeo Minamikawa(Tokushima Univ.)

10:30 AM - 10:45 AM

[18a-A501-6] Frequency-Modulation Mode-Locked Cr:ZnS Laser

〇(P)Zheyuan Zhang1, Daiki Okazaki1, Xiangbao Bu1, Ikki Morichika1, Satoshi Ashihara1 (1.Tokyo Univ. IIS)

Keywords:Active mode-locking, Mid-infrared laser

In this research, we for the first time demonstrate a mid-infrared (MIR), frequency-modulation (FM) mode-locked Cr:ZnS laser using an electro-optic phase modulator (EOPM). CW mode-locking with a repetition rate of 103 MHz and a narrow linewidth of ~0.1 nm centered at 2.2 µm is achieved.
Mode-locked MIR lasers are promising for applications in molecular spectroscopy, remote sensing, material processing, higher order harmonic generation, etc. Although passive mode-locking is commonly utilized for shorter pulse generation, active mode-locking provides alternative possibilities of much narrower linewidth and controllable repetition rate. The active mode-locking may be achieved by amplitude modulation (AM), but there are few high-speed intensity modulators in the MIR range longer than 2 µm. On the other hand, MIR phase modulators up to 20 GHz are commercially available, which fulfills the requirement for high-repetition-rate frequency modulation (FM) mode-locking.
The demonstrated FM mode-locked technique would be useful for the MIR pulse generation with high and/or tunable repetition rate and for applications where narrow spectral linewidth is important, such as high-precision vibrational spectroscopy.