Holmium Oxide Film as a Saturable Absorber for 2 μm Q-Switched Fiber Laser

• 来源期刊: 中国物理快报（英文版）
• 关键词: @@
• 年，卷（期）: 2017,（5）
• 页码范围: 48-51
• 页数: 4页
• 语种: 英文
• DOI: 10.1088/0256-307X/34/5/054201

摘要

This work reports on the use of the holmium oxide (Ho2O3) polymer film as a saturable absorber (SA) for generating stable Q-switching pulses operating in a 2-μm region in a thulium-doped fiber laser cavity.The SA is prepared by diluting a commercial Ho3O2 powder and then mixing it with polyvinyl alcohol (PVA) solution to form a Ho2O3-PVA film.A tiny part of the film about 1 mm× 1 mm in size is sandwiched between two fiber ferrules with the help of index matching gel.When incorporated in a laser cavity driven by a 1552-nm pump,stable Q-switching pulses are observed at 1955 nm within the pump power range of 363-491 mW.As the pump power increases within this range,the repetition rate rises from 26 kHz to 39 kHz,as the pulse width drops from 4.22 μs to 2.57μs.The laser operates with a signal-to-noise ratio of 47 dB,and the maximum output power and the pulse energy obtained are 2.67mW and 69n J,respectively.Our results successfully demonstrate that the Ho2O3 film can be used as a passive SA to generate a 2-μm pulse laser.