- Email: [email protected]
Passively Q-switched c-cut Nd:YVO4 laser using graphene-oxide as a saturable absorber
G Model
ARTICLE IN PRESS
IJLEO 57310 1–2
Optik xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Optik journal homepage: www.elsevier.de/ijleo
Passively Q-switched c-cut Nd:YVO4 laser using graphene-oxide as a saturable absorber
1
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Hong-Yi Lin a,∗ , Xiao-Hua Huang a , Xiao Liu b , Dong Sun a , Wen-Zhang Zhu a , Ying-Chao Xu a
4 a
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b
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School of Optoelectronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China School of Cultural Industries, Xiamen University of Technology, Xiamen 361024, China
7
a r t i c l e
8 20
i n f o
a b s t r a c t
9
Article history: Received 28 October 2015 Accepted 5 January 2016 Available online xxx
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We demonstrate a passively Q-switched c-cut Nd:YVO4 laser based on graphene-oxide (GO) as a saturable absorber (SA). The Q-switched laser has a low pump threshold of 1.5 W. The pulse repetition rate can be widely changed from 62 kHz to 386 kHz by increasing the pump power from 1.5 W to 3 W. The minimum pulse width is 246 ns and the maximum average output power is 514 mW. © 2016 Published by Elsevier GmbH.
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Keywords: Nd:YVO4 laser Graphene-oxide Passively Q-switched Saturable absorber
21
1. Introduction
2. Experiment setup
Compact all-solid-state Q-switched lasers are desirable for numerous applications such as laser ranging, environment sensing, material processing, and nonlinear optics [1]. Passively Q-switched techniques that use saturable absorbers have the advantages of potentially simplicity and lower cost in fabrication and operation since they require no radio-frequency drivers or high-voltage [2,3]. In recent years, graphene and graphene-oxide have been successfully used as passive Q-switchers for a variety of gain media such as Nd:YAG [4], Nd:YVO4 [5], Nd:La0.11 Y0.89 VO4 [6], Nd:GdVO4 [7], Nd:YLF [8] and Nd:GYSGG crystals [9]. In a Nd:YVO4 crystal, the stimulated emission cross-section orthogonal to the c axis, i.e. c-cut, is four times smaller than that parallel to the c axis, i.e. a-cut, for the emission wavelength at 1064 nm [10]. Therefore, the c-cut Nd:YVO4 crystal may be more appropriate than the a-cut Nd:YVO4 crystal with GO as SA. In this work, We demonstrate a GO passively Q-switched c-cut Nd:YVO4 laser. The minimum pulse width is only 246 ns, and the maximum average output power is 514 mW.
A compact concave-plane cavity is used in this experiment as shown in Fig. 1. The pump source is a fiber-coupled laser diode with a numerical aperture of 0.22. The 808 nm pump beam is coupled into a laser crystal by focusing optics. The input mirror M1 is a concave mirror with a curvature radius of 100 mm. It is coated with high-transmission at 808 nm on the plane surface, high-transmission at 808 nm and high-reflection at 1066 nm on the concave surface. The output mirror M2 is a plane mirror with a transmission of 15% at 1066 nm. The laser crystal is a c-cut 0.5 at.% Nd3+ -doped Nd:YVO4 crystal with a length of 8 mm and an aperture of 3 × 3 mm2 . Both faces of the Nd:YVO4 crystal are coated anti-reflection at 808 nm and 1066 nm. During the experiment, a simple GO SA is fabricated via the vertical evaporation technique [9]. The initial transmission of the GO SA is about 87% at 1066 nm.
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Q2
∗ Corresponding author. Tel.: +086 05926291258. E-mail address: [email protected] (H.-Y. Lin).
3. Experiment results and discussion Firstly, the continuous wave (CW) operation at 1066 nm is tested. The CW output power as a function of the incident pump power is shown in Fig. 2. The laser reaches the threshold at an incident pump power of about 0.45 W. An output power of 1148 mW is achieved at 1066 nm when the incident pump power is 3 W. The corresponding optical-to-optical conversion efficiency is 38.3%. The Q-switched pulses are appeared after the GO SA is inserted into the laser cavity. In order to compare with CW operation, the
http://dx.doi.org/10.1016/j.ijleo.2016.01.200 0030-4026/© 2016 Published by Elsevier GmbH.
Please cite this article in press as: H.-Y. Lin, et al., Passively Q-switched c-cut Nd:YVO4 laser using graphene-oxide as a saturable absorber, Optik - Int. J. Light Electron Opt. (2015), http://dx.doi.org/10.1016/j.ijleo.2016.01.200
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56 57 58 59 60 61 62 63
G Model
ARTICLE IN PRESS
IJLEO 57310 1–2
H.-Y. Lin et al. / Optik xxx (2015) xxx–xxx
2
Fig. 1. Experiment setup of the GO passively Q-switched c-cut Nd:YVO4 laser. 1200
CW output power Q-swtiched output power
Output power, mW
1000
800
Fig. 4. Pulse sequence of the passively Q-switched c-cut Nd:YVO4 laser at a pump power of 3 W.
600
4. Conclusion
400
200
0 0.5
1.0
1.5
2.0
2.5
3.0
Pump power, W Fig. 2. The CW and Q-switched output powers of the elaborated Nd:YVO4 laser.
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Acknowledgements
300
800
250 200
600
150
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
Fig. 3. Repetition rate and pulse width versus the incident pump power.
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This paper is supported by the Scientific Research Fund of Fujian Q3 Provincial Education Department of China (JA13231, JA15387) and the National Natural Science Foundation of China (11304259). The authors would thank Qi Song for his helpful discussions. References
Pump power, W
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82 83 84 85 86
87
88 89 90 91
92
200 1.4
67
81
400
50
66
80
1000
Pulse width, ns
Repetition rate, kHz
Repetition rate Pulse width
100
65
79
1200
350
64
In this paper, we report a passively Q-switched 1066 nm c-cut Nd:YVO4 laser by using a GO wafer as the saturable absorber. At the pump power of 3 W, the maximum average output power is 514 mW. The maximum repetition rate of 386 kHz with pulse width of 246 ns and per pulse energy of 1.33 J is also obtained at the same pump power. With further optimization of the parameters of the GO SA, higher average output power with better performance would be achieved in the future.
78
dependence of the average output power on the pump power is also shown in Fig. 2. For passively Q-switched operation, the threshold pump power increases to 1.5 W, and the average output power is lower than the CW regime under the same pump power. This is because of the incident loss of the GO SA. The maximum average output power is 514 mW at the pump power of 3 W, corresponding to optical-to-optical conversion efficiency of 17.1%. The pulse width and repetition rate of the passively Q-switched laser as a function of the pump power are also presented in Fig. 3. The pulse width is 1175 ns near the threshold and decreases to 246 ns at the pump power of 3 W, while the repetition rate increases with the pump power. The maximum repetition rate is 386 kHz, corresponding to the pulse energy of 1.33 J and the peak power of 5.41 W. The oscilloscope trace of the pulse at the pump power of 3 W is shown in Fig. 4.
[1] H.-Y. Lin, J. Guo, D.-Y. Ning, et al., LD end-pumped intracavity frequency doubled Yb:YAG laser, Opt. Commun. 281 (24) (2008) 6065–6067. [2] H. Lin, X. Meng, Y. Xu, et al., Parasitic oscillation in mid-infrared optical parametric generator based on PPMgLN, Optik 124 (16) (2013) 2511–2513. [3] Z. Yu, Y. Song, X. Dong, et al., Watt-level passively Q-switched double-cladding fiber laser based on graphene oxide saturable absorber, Appl. Opt. 52 (29) (2013) 7127–7131. [4] H. Lin, X. Huang, X. Liu, et al., Passively Q-switched Nd:YAG laser with multilayer graphene as a saturable absorber, J. Russ. Laser Res. 36 (3) (2015) 281–284. [5] T. Feng, S. Zhao, K. Yang, et al., Passively Q-switched lasers at 1.06 m with graphene oxide and carbon nanotubes D2 O dispersion, Opt. Mater. 36 (7) (2014) 1270–1273. [6] S. Han, X. Li, H. Xu, et al., Graphene Q-switched 0.9-m Nd:La0.11 Y0.89 VO4 laser, Chin. Opt. Lett. 12 (1) (2014) 011401. [7] Y.G. Wang, H.R. Chen, X.M. Wen, et al., A highly efficient graphene oxide absorber for Q-switched Nd:GdVO4 lasers, Nanotechnology 22 (45) (2011) 455203. [8] P. Matía-Hernando, J.M. Guerra, R. Weigand, An Nd:YLF laser Q-switched by a monolayer-graphene saturable-absorber mirror, Laser Phys. 23 (2) (2013) 025003. [9] Q. Song, G. Wang, B. Zhang, et al., Diode-pumped passively dual-wavelength Q-switched Nd:GYSGG laser using graphene oxide as the saturable absorber, Appl. Opt. 54 (10) (2015) 2688–2692. [10] Y.-F. Chen, Y.P. Lan, Comparison between c-cut and a-cut Nd:YVO4 lasers passively Q-switched with a Cr4+ :YAG saturable absorber, Appl. Phys. B 74 (4) (2002) 415–418.
Please cite this article in press as: H.-Y. Lin, et al., Passively Q-switched c-cut Nd:YVO4 laser using graphene-oxide as a saturable absorber, Optik - Int. J. Light Electron Opt. (2015), http://dx.doi.org/10.1016/j.ijleo.2016.01.200
93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118
ARTICLE IN PRESS
IJLEO 57310 1–2
Optik xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Optik journal homepage: www.elsevier.de/ijleo
Passively Q-switched c-cut Nd:YVO4 laser using graphene-oxide as a saturable absorber
1
2
3
Q1
Hong-Yi Lin a,∗ , Xiao-Hua Huang a , Xiao Liu b , Dong Sun a , Wen-Zhang Zhu a , Ying-Chao Xu a
4 a
5
b
6
School of Optoelectronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China School of Cultural Industries, Xiamen University of Technology, Xiamen 361024, China
7
a r t i c l e
8 20
i n f o
a b s t r a c t
9
Article history: Received 28 October 2015 Accepted 5 January 2016 Available online xxx
10 11 12 13 14
We demonstrate a passively Q-switched c-cut Nd:YVO4 laser based on graphene-oxide (GO) as a saturable absorber (SA). The Q-switched laser has a low pump threshold of 1.5 W. The pulse repetition rate can be widely changed from 62 kHz to 386 kHz by increasing the pump power from 1.5 W to 3 W. The minimum pulse width is 246 ns and the maximum average output power is 514 mW. © 2016 Published by Elsevier GmbH.
19
Keywords: Nd:YVO4 laser Graphene-oxide Passively Q-switched Saturable absorber
21
1. Introduction
2. Experiment setup
Compact all-solid-state Q-switched lasers are desirable for numerous applications such as laser ranging, environment sensing, material processing, and nonlinear optics [1]. Passively Q-switched techniques that use saturable absorbers have the advantages of potentially simplicity and lower cost in fabrication and operation since they require no radio-frequency drivers or high-voltage [2,3]. In recent years, graphene and graphene-oxide have been successfully used as passive Q-switchers for a variety of gain media such as Nd:YAG [4], Nd:YVO4 [5], Nd:La0.11 Y0.89 VO4 [6], Nd:GdVO4 [7], Nd:YLF [8] and Nd:GYSGG crystals [9]. In a Nd:YVO4 crystal, the stimulated emission cross-section orthogonal to the c axis, i.e. c-cut, is four times smaller than that parallel to the c axis, i.e. a-cut, for the emission wavelength at 1064 nm [10]. Therefore, the c-cut Nd:YVO4 crystal may be more appropriate than the a-cut Nd:YVO4 crystal with GO as SA. In this work, We demonstrate a GO passively Q-switched c-cut Nd:YVO4 laser. The minimum pulse width is only 246 ns, and the maximum average output power is 514 mW.
A compact concave-plane cavity is used in this experiment as shown in Fig. 1. The pump source is a fiber-coupled laser diode with a numerical aperture of 0.22. The 808 nm pump beam is coupled into a laser crystal by focusing optics. The input mirror M1 is a concave mirror with a curvature radius of 100 mm. It is coated with high-transmission at 808 nm on the plane surface, high-transmission at 808 nm and high-reflection at 1066 nm on the concave surface. The output mirror M2 is a plane mirror with a transmission of 15% at 1066 nm. The laser crystal is a c-cut 0.5 at.% Nd3+ -doped Nd:YVO4 crystal with a length of 8 mm and an aperture of 3 × 3 mm2 . Both faces of the Nd:YVO4 crystal are coated anti-reflection at 808 nm and 1066 nm. During the experiment, a simple GO SA is fabricated via the vertical evaporation technique [9]. The initial transmission of the GO SA is about 87% at 1066 nm.
15 16 17 18
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39
Q2
∗ Corresponding author. Tel.: +086 05926291258. E-mail address: [email protected] (H.-Y. Lin).
3. Experiment results and discussion Firstly, the continuous wave (CW) operation at 1066 nm is tested. The CW output power as a function of the incident pump power is shown in Fig. 2. The laser reaches the threshold at an incident pump power of about 0.45 W. An output power of 1148 mW is achieved at 1066 nm when the incident pump power is 3 W. The corresponding optical-to-optical conversion efficiency is 38.3%. The Q-switched pulses are appeared after the GO SA is inserted into the laser cavity. In order to compare with CW operation, the
http://dx.doi.org/10.1016/j.ijleo.2016.01.200 0030-4026/© 2016 Published by Elsevier GmbH.
Please cite this article in press as: H.-Y. Lin, et al., Passively Q-switched c-cut Nd:YVO4 laser using graphene-oxide as a saturable absorber, Optik - Int. J. Light Electron Opt. (2015), http://dx.doi.org/10.1016/j.ijleo.2016.01.200
40
41 42 43 44 45 46 47 48 49 50 51 52 53 54
55
56 57 58 59 60 61 62 63
G Model
ARTICLE IN PRESS
IJLEO 57310 1–2
H.-Y. Lin et al. / Optik xxx (2015) xxx–xxx
2
Fig. 1. Experiment setup of the GO passively Q-switched c-cut Nd:YVO4 laser. 1200
CW output power Q-swtiched output power
Output power, mW
1000
800
Fig. 4. Pulse sequence of the passively Q-switched c-cut Nd:YVO4 laser at a pump power of 3 W.
600
4. Conclusion
400
200
0 0.5
1.0
1.5
2.0
2.5
3.0
Pump power, W Fig. 2. The CW and Q-switched output powers of the elaborated Nd:YVO4 laser.
400
Acknowledgements
300
800
250 200
600
150
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
Fig. 3. Repetition rate and pulse width versus the incident pump power.
69 70 71 72 73 74 75 76 77
This paper is supported by the Scientific Research Fund of Fujian Q3 Provincial Education Department of China (JA13231, JA15387) and the National Natural Science Foundation of China (11304259). The authors would thank Qi Song for his helpful discussions. References
Pump power, W
68
82 83 84 85 86
87
88 89 90 91
92
200 1.4
67
81
400
50
66
80
1000
Pulse width, ns
Repetition rate, kHz
Repetition rate Pulse width
100
65
79
1200
350
64
In this paper, we report a passively Q-switched 1066 nm c-cut Nd:YVO4 laser by using a GO wafer as the saturable absorber. At the pump power of 3 W, the maximum average output power is 514 mW. The maximum repetition rate of 386 kHz with pulse width of 246 ns and per pulse energy of 1.33 J is also obtained at the same pump power. With further optimization of the parameters of the GO SA, higher average output power with better performance would be achieved in the future.
78
dependence of the average output power on the pump power is also shown in Fig. 2. For passively Q-switched operation, the threshold pump power increases to 1.5 W, and the average output power is lower than the CW regime under the same pump power. This is because of the incident loss of the GO SA. The maximum average output power is 514 mW at the pump power of 3 W, corresponding to optical-to-optical conversion efficiency of 17.1%. The pulse width and repetition rate of the passively Q-switched laser as a function of the pump power are also presented in Fig. 3. The pulse width is 1175 ns near the threshold and decreases to 246 ns at the pump power of 3 W, while the repetition rate increases with the pump power. The maximum repetition rate is 386 kHz, corresponding to the pulse energy of 1.33 J and the peak power of 5.41 W. The oscilloscope trace of the pulse at the pump power of 3 W is shown in Fig. 4.
[1] H.-Y. Lin, J. Guo, D.-Y. Ning, et al., LD end-pumped intracavity frequency doubled Yb:YAG laser, Opt. Commun. 281 (24) (2008) 6065–6067. [2] H. Lin, X. Meng, Y. Xu, et al., Parasitic oscillation in mid-infrared optical parametric generator based on PPMgLN, Optik 124 (16) (2013) 2511–2513. [3] Z. Yu, Y. Song, X. Dong, et al., Watt-level passively Q-switched double-cladding fiber laser based on graphene oxide saturable absorber, Appl. Opt. 52 (29) (2013) 7127–7131. [4] H. Lin, X. Huang, X. Liu, et al., Passively Q-switched Nd:YAG laser with multilayer graphene as a saturable absorber, J. Russ. Laser Res. 36 (3) (2015) 281–284. [5] T. Feng, S. Zhao, K. Yang, et al., Passively Q-switched lasers at 1.06 m with graphene oxide and carbon nanotubes D2 O dispersion, Opt. Mater. 36 (7) (2014) 1270–1273. [6] S. Han, X. Li, H. Xu, et al., Graphene Q-switched 0.9-m Nd:La0.11 Y0.89 VO4 laser, Chin. Opt. Lett. 12 (1) (2014) 011401. [7] Y.G. Wang, H.R. Chen, X.M. Wen, et al., A highly efficient graphene oxide absorber for Q-switched Nd:GdVO4 lasers, Nanotechnology 22 (45) (2011) 455203. [8] P. Matía-Hernando, J.M. Guerra, R. Weigand, An Nd:YLF laser Q-switched by a monolayer-graphene saturable-absorber mirror, Laser Phys. 23 (2) (2013) 025003. [9] Q. Song, G. Wang, B. Zhang, et al., Diode-pumped passively dual-wavelength Q-switched Nd:GYSGG laser using graphene oxide as the saturable absorber, Appl. Opt. 54 (10) (2015) 2688–2692. [10] Y.-F. Chen, Y.P. Lan, Comparison between c-cut and a-cut Nd:YVO4 lasers passively Q-switched with a Cr4+ :YAG saturable absorber, Appl. Phys. B 74 (4) (2002) 415–418.
Please cite this article in press as: H.-Y. Lin, et al., Passively Q-switched c-cut Nd:YVO4 laser using graphene-oxide as a saturable absorber, Optik - Int. J. Light Electron Opt. (2015), http://dx.doi.org/10.1016/j.ijleo.2016.01.200
93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118