- Special Issue
- Photonics Based on Two Dimensional Materials
- 17 Article (s)
Sign of differential reflection and transmission in pump-probe spectroscopy of graphene on dielectric substrate
Chengmin Gao, Xin Zhao, Jun Yao, Xiao-Qing Yan, Xiang-Tian Kong, Yongsheng Chen, Zhi-Bo Liu, and Jian-Guo Tian
Pump-probe differential reflection and transmission spectroscopy is a very effective tool to study the nonequili-brium carrier dynamics of graphene. The reported sign of differential reflection from graphene is not explicitly explained and not consistent. Here, we study the differential reflection and transmission signals of graphene on a dielectric substrate. The results reveal the sign of differential reflection changes with the incident direction of the probe beam with respect to the substrate. The obtained theory can be applied to predict the differential signals of other two-dimensional materials placed on various dielectric substrates. Pump-probe differential reflection and transmission spectroscopy is a very effective tool to study the nonequili-brium carrier dynamics of graphene. The reported sign of differential reflection from graphene is not explicitly explained and not consistent. Here, we study the differential reflection and transmission signals of graphene on a dielectric substrate. The results reveal the sign of differential reflection changes with the incident direction of the probe beam with respect to the substrate. The obtained theory can be applied to predict the differential signals of other two-dimensional materials placed on various dielectric substrates.
Photonics Research
- Publication Date: Mar. 13, 2015
- Vol. 3, Issue 2, 020000A1 (2015)
Band-gap modulation of two-dimensional saturable absorbers for solid-state lasers
Shuxian Wang, Haohai Yu, and Huaijin Zhang
Due to the manifestation of fascinating physical phenomena and materials science, two-dimensional (2D) materials have recently attracted enormous research interest with respect to the fields of electronics and optoelectronics. There have been in-depth investigations of the nonlinear properties with respect to saturable absorption, and many 2D materials show potential application in optical switches for passive pulsed lasers. However, the Eigen band-gap determines the responding wavelength band and constrains the applications. In this paper, based on band-gap engineering, some different types of 2D broadband saturable absorbers are reviewed in detail, including molybdenum disulfide (MoS2), vanadium dioxide (VO2), graphene, and the Bi2Se3 topological insulator. The results suggest that the band-gap modification should play important roles in 2D broadband saturable materials and can provide some inspiration for the exploration and design of 2D nanodevices. Due to the manifestation of fascinating physical phenomena and materials science, two-dimensional (2D) materials have recently attracted enormous research interest with respect to the fields of electronics and optoelectronics. There have been in-depth investigations of the nonlinear properties with respect to saturable absorption, and many 2D materials show potential application in optical switches for passive pulsed lasers. However, the Eigen band-gap determines the responding wavelength band and constrains the applications. In this paper, based on band-gap engineering, some different types of 2D broadband saturable absorbers are reviewed in detail, including molybdenum disulfide (MoS2), vanadium dioxide (VO2), graphene, and the Bi2Se3 topological insulator. The results suggest that the band-gap modification should play important roles in 2D broadband saturable materials and can provide some inspiration for the exploration and design of 2D nanodevices.
Photonics Research
- Publication Date: Mar. 16, 2015
- Vol. 3, Issue 2, 02000A10 (2015)
Dual-wavelength single-longitudinal-mode fiber laser with switchable wavelength spacing based on a graphene saturable absorber
Jingjuan Zhou, Aiping Luo, Zhichao Luo, Xudong Wang, Xinhuan Feng, and Bai-ou Guan
We propose and demonstrate a dual-wavelength single-longitudinal-mode (SLM) fiber laser with switchable wavelength spacing based on a graphene saturable absorber (GSA) and a WaveShaper. By virtue of the excellent saturable absorption ability of graphene, the linewidths of the lasing wavelengths can be effectively reduced and eventually SLM operation can be obtained. The linewidths of both wavelengths are measured to be narrower than 7.3 kHz. The obtained results suggest that the graphene would be a good candidate nonlinear optical material for applications in related photonic fields, such as SLM oscillation generation for microwave generation and optical sensing. We propose and demonstrate a dual-wavelength single-longitudinal-mode (SLM) fiber laser with switchable wavelength spacing based on a graphene saturable absorber (GSA) and a WaveShaper. By virtue of the excellent saturable absorption ability of graphene, the linewidths of the lasing wavelengths can be effectively reduced and eventually SLM operation can be obtained. The linewidths of both wavelengths are measured to be narrower than 7.3 kHz. The obtained results suggest that the graphene would be a good candidate nonlinear optical material for applications in related photonic fields, such as SLM oscillation generation for microwave generation and optical sensing.
Photonics Research
- Publication Date: Mar. 17, 2015
- Vol. 3, Issue 2, 02000A21 (2015)
Nanosecond-pulsed, dual-wavelength, passively Q-switched ytterbium-doped bulk laser based on few-layer MoS2 saturable absorber
Fei Lou, Ruwei Zhao, Jingliang He, Zhitai Jia, Xiancui Su, Zhaowei Wang, Jia Hou, and Baitao Zhang
A compact saturable absorber mirror (SAM) based on few-layer molybdenum disulfide (MoS2) nanoplatelets was fabricated and successfully used as an efficient saturable absorber (SA) for the passively Q-switched solid-state laser at 1 μm wavelength. Pulses as short as 182 ns were obtained from a ytterbium-doped (Yb:LGGG) bulk laser Q-switched by the MoS2 SAM, which we believe to be the shortest one ever achieved from the MoS2 SAs-based Q-switched bulk lasers. A maximum average output power of 0.6 W was obtained with a slope efficiency of 24%, corresponding to single pulse energy up to 1.8 μJ. In addition, the simultaneous dual-wavelength Q-switching at 1025.2 and 1028.1 nm has been successfully achieved. The results indicate the promising potential of few-layer MoS2 nanoplatelets as nonlinear optical switches for achieving efficient pulsed bulk lasers. A compact saturable absorber mirror (SAM) based on few-layer molybdenum disulfide (MoS2) nanoplatelets was fabricated and successfully used as an efficient saturable absorber (SA) for the passively Q-switched solid-state laser at 1 μm wavelength. Pulses as short as 182 ns were obtained from a ytterbium-doped (Yb:LGGG) bulk laser Q-switched by the MoS2 SAM, which we believe to be the shortest one ever achieved from the MoS2 SAs-based Q-switched bulk lasers. A maximum average output power of 0.6 W was obtained with a slope efficiency of 24%, corresponding to single pulse energy up to 1.8 μJ. In addition, the simultaneous dual-wavelength Q-switching at 1025.2 and 1028.1 nm has been successfully achieved. The results indicate the promising potential of few-layer MoS2 nanoplatelets as nonlinear optical switches for achieving efficient pulsed bulk lasers.
Photonics Research
- Publication Date: Mar. 23, 2015
- Vol. 3, Issue 2, 02000A25 (2015)
Few-layer MoS2 saturable absorbers for short-pulse laser technology: current status and future perspectives [Invited]
R. I., R. C., G. Hu, F. Torrisi, M. Zhang, T. Hasan, and E. J.
Few-layer molybdenum disulfide (MoS2) is emerging as a promising quasi-two-dimensional material for photonics and optoelectronics, further extending the library of suitable layered nanomaterials with exceptional optical properties for use in saturable absorber devices that enable short-pulse generation in laser systems. In this work, we catalog and review the nonlinear optical properties of few-layer MoS2, summarize recent progress in processing and integration into saturable absorber devices, and comment on the current status and future perspectives of MoS2-based pulsed lasers. Few-layer molybdenum disulfide (MoS2) is emerging as a promising quasi-two-dimensional material for photonics and optoelectronics, further extending the library of suitable layered nanomaterials with exceptional optical properties for use in saturable absorber devices that enable short-pulse generation in laser systems. In this work, we catalog and review the nonlinear optical properties of few-layer MoS2, summarize recent progress in processing and integration into saturable absorber devices, and comment on the current status and future perspectives of MoS2-based pulsed lasers.
Photonics Research
- Publication Date: Mar. 24, 2015
- Vol. 3, Issue 2, 02000A30 (2015)
Soliton fiber laser mode locked with two types of film-based Bi2Te3 saturable absorbers
Dong Mao, Biqiang Jiang, Xuetao Gan, Chaojie Ma, Yu Chen, Chujun Zhao, Han Zhang, Jianbang Zheng, and Jianlin Zhao
We propose a low-threshold soliton fiber laser passively mode locked with two different types of film-like saturable absorbers, one of which is fabricated by mixing Bi2Te3 with de-ionized water, as well as polyvinyl alcohol (PVA), and then evaporating them in a Petri dish, and the other of which is prepared by directly dropping Bi2Te3 solution on the PVA film. Both Bi2Te3–PVA films exhibit outstanding features of low loss, high flexibility, and easy synthesis. By incorporating Bi2Te3–PVA films into fiber lasers, stable single-soliton emissions are obtained at a low pump power of 13 mW. Our results suggest that the Bi2Te3 can work as a promising mode locker for ultrafast lasers, while PVA is an excellent host for fabricating high-performance film-based saturable absorbers. We propose a low-threshold soliton fiber laser passively mode locked with two different types of film-like saturable absorbers, one of which is fabricated by mixing Bi2Te3 with de-ionized water, as well as polyvinyl alcohol (PVA), and then evaporating them in a Petri dish, and the other of which is prepared by directly dropping Bi2Te3 solution on the PVA film. Both Bi2Te3–PVA films exhibit outstanding features of low loss, high flexibility, and easy synthesis. By incorporating Bi2Te3–PVA films into fiber lasers, stable single-soliton emissions are obtained at a low pump power of 13 mW. Our results suggest that the Bi2Te3 can work as a promising mode locker for ultrafast lasers, while PVA is an excellent host for fabricating high-performance film-based saturable absorbers.
Photonics Research
- Publication Date: Mar. 26, 2015
- Vol. 3, Issue 2, 02000A43 (2015)
Passive Q-switching and Q-switched mode-locking operations of 2 μm Tm:CLNGG laser with MoS2 saturable absorber mirror
L. C., G. Q., P. Yuan, L. J., S. X., H. H., and H. J.
With MoS2 as saturable absorber, passive Q-switching and Q-switched mode-locking operations of a Tm-doped calcium lithium niobium gallium garnet (Tm:CLNGG) laser were experimentally demonstrated. The Q-switched laser emitted a maximum average output power of 62 mW and highest pulse energy of 0.72 μJ. Q-switched mode locking was also obtained in the experiment. The research results will open up applications of MoS2 at the mid-infrared wavelength. With MoS2 as saturable absorber, passive Q-switching and Q-switched mode-locking operations of a Tm-doped calcium lithium niobium gallium garnet (Tm:CLNGG) laser were experimentally demonstrated. The Q-switched laser emitted a maximum average output power of 62 mW and highest pulse energy of 0.72 μJ. Q-switched mode locking was also obtained in the experiment. The research results will open up applications of MoS2 at the mid-infrared wavelength.
Photonics Research
- Publication Date: Mar. 26, 2015
- Vol. 3, Issue 2, 02000A47 (2015)
Tunable nonlinear refractive index of two-dimensional MoS2, WS2, and MoSe2 nanosheet dispersions [Invited]
Gaozhong Wang, Saifeng Zhang, Xiaoyan Zhang, Long Zhang, Ya Cheng, Daniel Fox, Hongzhou Zhang, Jonathan N., Werner J., and Jun Wang
Liquid-phase-exfoliation technology was utilized to prepare layered MoS2, WS2, and MoSe2 nanosheets in cyclohexylpyrrolidone. The nonlinear optical response of these nanosheets in dispersions was investigated by observing spatial self-phase modulation (SSPM) using a 488 nm continuous wave laser beam. The diffraction ring patterns of SSPM were found to be distorted along the vertical direction right after the laser traversing the nanosheet dispersions. The nonlinear refractive index of the three transition metal dichalcogenides dispersions n2 was measured to be ～10 7 cm2·W 1, and the third-order nonlinear susceptibility χ(3) ～ 10 9 esu. The relative change of effective nonlinear refractive index Δn2e∕n2e of the MoS2, WS2, and MoSe2 dispersions can be modulated 0.012– 0.240, 0.029–0.154, and 0.091–0.304, respectively, by changing the incident intensities. Our experimental results imply novel potential application of two-dimensional transition metal dichalcogenides in nonlinear phase modulation devices. Liquid-phase-exfoliation technology was utilized to prepare layered MoS2, WS2, and MoSe2 nanosheets in cyclohexylpyrrolidone. The nonlinear optical response of these nanosheets in dispersions was investigated by observing spatial self-phase modulation (SSPM) using a 488 nm continuous wave laser beam. The diffraction ring patterns of SSPM were found to be distorted along the vertical direction right after the laser traversing the nanosheet dispersions. The nonlinear refractive index of the three transition metal dichalcogenides dispersions n2 was measured to be ～10 7 cm2·W 1, and the third-order nonlinear susceptibility χ(3) ～ 10 9 esu. The relative change of effective nonlinear refractive index Δn2e∕n2e of the MoS2, WS2, and MoSe2 dispersions can be modulated 0.012– 0.240, 0.029–0.154, and 0.091–0.304, respectively, by changing the incident intensities. Our experimental results imply novel potential application of two-dimensional transition metal dichalcogenides in nonlinear phase modulation devices.
Photonics Research
- Publication Date: Mar. 26, 2016
- Vol. 3, Issue 2, 02000A51 (2015)
Mode-locking of fiber lasers using novel two-dimensional nanomaterials: graphene and topological insulators [Invited]
Grzegorz Sobon|Laser & Fiber Electronics Group, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, and 50-370 Wroclaw
The paper summarizes the recent achievements in the area of ultrafast fiber lasers mode-locked with so-called lowdimensional nanomaterials: graphene, topological insulators (Bi2Te3, Bi2Se3, Sb2Te3), and transition metal sulfide semiconductors, like molybdenum disulfide (MoS2). The most important experimental achievements are described and compared. Additionally, new original results on ultrashort pulse generation at 1.94 μm wavelength using graphene are presented. The designed Tm-doped fiber laser utilizes multilayer graphene as a saturable absorber and generates 654 fs pulses at 1940 nm wavelength, which are currently the shortest pulses generated from a Tm-doped fiber laser with a graphene-based saturable absorber. The paper summarizes the recent achievements in the area of ultrafast fiber lasers mode-locked with so-called lowdimensional nanomaterials: graphene, topological insulators (Bi2Te3, Bi2Se3, Sb2Te3), and transition metal sulfide semiconductors, like molybdenum disulfide (MoS2). The most important experimental achievements are described and compared. Additionally, new original results on ultrashort pulse generation at 1.94 μm wavelength using graphene are presented. The designed Tm-doped fiber laser utilizes multilayer graphene as a saturable absorber and generates 654 fs pulses at 1940 nm wavelength, which are currently the shortest pulses generated from a Tm-doped fiber laser with a graphene-based saturable absorber.
Photonics Research
- Publication Date: Mar. 26, 2015
- Vol. 3, Issue 2, 02000A56 (2015)
Generation of cascaded four-wave-mixing with graphene-coated microfiber
Y. Wu, B. C., Q. Y., X. L., X. Y., Y. J., Y. Gong, W. L., Z. G., Y. F., and K. S.
A graphene-coated microfiber (GCM)-based hybrid waveguide structure formed by wrapping monolayer graphene around a microfiber with length of several millimeters is pumped by a nanosecond laser at ～1550 nm, and multiorder cascaded four-wave-mixing (FWM) is effectively generated. By optimizing both the detuning and the pump power, such a GCM device with high nonlinearity and compact size would have potential for a wide range ofFWM applications, such as phase-sensitive amplification, multi-wavelength filter, all-optical regeneration and frequency conversion, and so on. A graphene-coated microfiber (GCM)-based hybrid waveguide structure formed by wrapping monolayer graphene around a microfiber with length of several millimeters is pumped by a nanosecond laser at ～1550 nm, and multiorder cascaded four-wave-mixing (FWM) is effectively generated. By optimizing both the detuning and the pump power, such a GCM device with high nonlinearity and compact size would have potential for a wide range ofFWM applications, such as phase-sensitive amplification, multi-wavelength filter, all-optical regeneration and frequency conversion, and so on.
Photonics Research
- Publication Date: Mar. 27, 2015
- Vol. 3, Issue 2, 02000A64 (2015)
Photonics Based on Two Dimensional Materials
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