Pulsed operation of Yb-doped planar waveguide lasers by employing nanocarbons
Pulsed operation of Yb-doped planar waveguide lasers by employing nanocarbons
- 주제(키워드) planar waveguide laser , solid-state laser , Q-switching , mode-locking , carbon nanotube , graphene
- 발행기관 아주대학교
- 지도교수 Fabian Rotermund, Dong-Il Yeom
- 발행년도 2017
- 학위수여년월 2017. 2
- 학위명 박사
- 학과 및 전공 일반대학원 에너지시스템학과
- 실제URI http://www.dcollection.net/handler/ajou/000000024978
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
As part of the requirements for a compact pulsed coherent source, solid-state waveguide lasers have been extensively investigated as a low-gain, low-lasing threshold, and a cost-effective solution with significant potential as a future on-chip integrated light source. The direct application of the evanescent field interaction scheme to the waveguide gain provides a much more simple, compact, robust, and integrated platform for the pulsed operation of solid-state waveguide laser. To use the evanescent field interaction scheme, a saturable absorber that can be simply deposited on the waveguide is needed due to the difficulty of the epitaxy of the semiconductor based saturable absorber on the top side of the monolithic waveguide gain. In this thesis, the pulsed operation of a solid-state Yb:KYW planar waveguide lasers is researched with nanocarbon materials. We first achieve a stable Q-switched operation of the Yb:KYW planar waveguide laser by evanescent field interaction with nanocarbons for the first time. Carbon nanotubes and graphene are deposited on a top side of the Yb:KYW planar waveguide, respectively, and facilitate the Q-switching of the Yb:KYW planar waveguide laser. A comparative analysis of direct and evanescent field interaction schemes is subsequently conducted at various positions of the carbon nanotube saturable absorber, such as an output coupler, an end mirror, and on a top side of the planar waveguide. Each case exhibits stable Q-switched operation, and it was confirmed that the maximum intensity at the saturable absorber of the evanescent field interaction scheme is 1,000 times lower than that of direct field interaction scheme of the end mirror. Moreover, a mode-locked operation for the solid-state Yb:KYW planar waveguide laser is proposed. To fulfill the cw mode-locking conditions, an extended cavity configuration is adopted and the carbon nanotube saturable absorber is deposited on the output coupler. The laser exhibited stable cw mode-locked operation.
more목차
1. Introduction and theoretical background 1
1.1 Introduction 1
1.2 Saturable absorber 5
1.3 Pulsed operation - Q-switching and mode-locking 7
1.4 Yb:KYW gain medium 14
1.5 Nanocarbon materials - carbon nanotube and graphene 16
1.6 Optical waveguide structure 22
1.7 Lens-insertion Fabry-Perot resonator configuration for the planar waveguide laser 27
2. Sample Preparation 32
2.1 Yb:KYW planar waveguide 32
2.2 Nanocarbon based saturable absorber 35
3. Q-switched Yb:KYW planar waveguide lasers by evanescent field interaction with nanocarbon materials 38
3.1 Motivation 38
3.2 Carbon nanotube Q-switched Yb:KYW planar waveguide laser 40
3.3 Graphene Q-switched Yb:KYW planar waveguide laser 48
3.4 Summary 61
4. Comparative analysis of carbon nanotube Q-switched Yb:KYW planar waveguide lasers 62
4.1 Motivation 62
4.2 Carbon nanotube Q-switched Yb:KYW planar waveguide lasers 64
4.3 Comparative analysis of carbon nanotube Q-switched Yb:KYW planar waveguide laser 70
4.4 Summary 77
5. Carbon nanotube mode-locked Yb:KYW solid-state planar waveguide laser 78
5.1 Motivation 78
5.2 Carbon nanotube mode-locked Yb:KYW solid-state planar waveguide laser 80
5.3 Analysis of cw mode-locking conditions of carbon nanotube mode-locked solid-state waveguide laser 86
5.4 Summary 88
6. Conclusion 89
Reference 92
Publication list 99
