Broadband 1T-titanium selenide-based saturable absorbers for solid-state bulk lasers

Yang

et al. 2019

Nanomaterials

Two-dimensional (2D) layered semiconductor materials, such as transition metal dichalcogenides (TMDCs), have attracted considerable interests because of their intriguing optical and electronic properties. Controlled growth of TMDC crystals with large grain size and atomically smooth surface is indeed desirable but remains challenging due to excessive nucleation. Here, we have synthesized high-quality monolayer, bilayer MoSe2 triangular crystals, and continuous thin films with controlled nucleation density via reverse-flow chemical vapor deposition (CVD). High crystallinity and good saturated absorption performance of MoSe2 have been systematically investigated and carefully demonstrated. Optimized nucleation and uniform morphology could be achieved via fine-tuning reverse-flow switching time, growth time and temperature, with corresponding growth kinetics proposed. Our work opens up a new approach for controllable synthesis of monolayer TMDC crystals with high yield and reliability, which promote surface/interface engineering of 2D semiconductors towards van der Waals heterostructure device applications.

Section: Resultsmentioning

confidence: 99%

Synthesis of Monolayer MoSe2 with Controlled Nucleation via Reverse-Flow Chemical Vapor Deposition

Yang

et al. 2019

Nanomaterials

“…One of the main factors that hinders the development of photonics and optoelectronics is the lack of materials with broad‐band optical response and strong light–matter interaction. Therefore, it is an urgent need and many efforts have been devoted to searching for this kind of novel materials …”

Section: Introductionmentioning

confidence: 99%

Two‐Dimensional GeP‐Based Broad‐Band Optical Switches and Photodetectors

Nie

Advanced Optical Materials

et al. 2019

Self Cite

photonics and optoelectronics is the lack of materials with broad-band optical response and strong light-matter interaction. Therefore, it is an urgent need and many efforts have been devoted to searching for this kind of novel materials. [2][3][4][5] The broad-band optical response of 2D nanomaterial is related to the unique band structure and electronic properties. [1] Graphene exhibits a wide-spectral photonic response from ultraviolet to the radio-wave regimes owing to its gapless and conical-shape band structure. However, lack of intrinsic bandgap makes graphene-based devices suffer from relatively small on/off ratio, large dark current, and poor photo response. The relative low absorption and high non-saturable loss of graphene in optical response limit its extensive applications. [6][7][8][9] Following graphene, the most studied 2D transition metal dichalcogenides (TMDCs) possess a bandgap ranging from 1.0 to 2.0 eV, indicating their practical optoelectronic applications are not available in midinfrared (MIR) wavelength range. [10,11] After graphene and TMDCs, black phosphorus (BP), the most thermodynamically stable allotrope of phosphorus, has been thoroughly studied as a novel 2D layered material since early 2014. [12] It has triggered significant interests in both scientific research and potential electronic, optoelectronic, and biomedicine applications because of its unique and exotic properties. [13][14][15] Layered BP has a direct bandgap with layer-dependent variation over ≈0.3-2.0 eV, which gives rise to broad-band optical properties from visible to MIR region. The intrinsic layer-dependent direct bandgap gives rise to high on/off ratio and low dark current for electronic devices and makes BP an appropriate 2D material for MIR photonic applications. Moreover, the bandgap of BP can be efficiently tuned by electrical gating, which should pave the way for optoelectronic devices. [16] BP presents puckered structure with in-plane anisotropy, which results in specific dichroic optical properties of light absorption and photoluminescence. [17] However, easy oxidation under ambient environment is the biggest obstacle that significantly impedes its practical applications. [14,[18][19][20][21][22] Therefore, how to improve the long-term stability of BP has become a challenge.Germanium phosphide (GeP), a typical 2D group IV-V semiconductor, has attracted significant attention due to the advantages of higher thermodynamic stability than black phosphorus (BP), widely tunable bandgap, high carrier mobility, and in-plane anisotropy. However, its photonic and optoelectronic properties have not been extensively explored so far. Herein, large size and high-quality GeP single bulk crystal is successfully grown by flux method and stripped into 2D nanosheets with liquid phase exfoliation (LPE) and spin-coating methods. The broad-band photonic and optoelectronic properties of 2D GeP nanosheets are systematically investigated. First principles calculations are performed to verify its widely tunable bandgap from 0.43 eV f...

“…These advantages make 1T‐TiSe 2 a promising broadband SA for passively Q‐switched and mode‐locked lasers. Our group fabricated large‐area high‐quality 1T‐TiSe 2 films with the LPE method and obtained a broadband passive Q‐switching solid‐state laser with a 1T‐TiSe 2 SA, achieving pulse lasers operating at 1.0 and 1.3 µm with pulse widths of 483 and 344 ns ( Figure a) …”

Section: All Solid‐state Pulsed Bulk Laser Generation With 2d Layeredmentioning

confidence: 99%

“…a) Passively Q‐switched solid‐state bulk lasers with 1T‐TiSe 2 SA operating at 1.0 µm: the linear and nonlinear optical transimission spectrum of 1T‐TiSe 2 SA, and the pulse train and single pulse profile of the passively Q‐switched laser. Reproduced with permission . Copyright 2018, Royal Society of Chemistry.…”

Section: All Solid‐state Pulsed Bulk Laser Generation With 2d Layeredmentioning

confidence: 99%

Recent Progress in 2D Material‐Based Saturable Absorbers for All Solid‐State Pulsed Bulk Lasers

Zhang

Liu

Laser & Photonics Reviews

et al. 2019

Self Cite

137

All solid‐state pulsed lasers (ASSPLs) play a significant role in the fields of medical, military, industry, and scientific research. Passive Q‐switching and mode‐locking are two of the most effective techniques for generating ASSPLs, in which a saturable absorber (SA) is the key element that has great impact on laser output parameters. Recently, 2D layered materials have been widely studied due to their intriguing properties. Their advantages of ultrafast dynamic processing, excellent nonlinear optical response, broadband operation, and easy fabrication and integration with lasers, enable them to be excellent SAs. Herein, the recent progress of ASSPLs with 2D layered material‐based SAs is reviewed, including a brief introduction of the fundamental characteristics, fabrication methods, characterization techniques of ultrafast dynamics, and nonlinear optical properties of 2D materials, design criteria of passively Q‐switched and mode‐locked bulk lasers, and their applications in ASSPLs. Finally, the potential developments and perspectives on 2D material‐based ASSPLs are also highlighted.