Advances in vanadate laser crystals at a lasing wavelength of 1 micrometer

Advanced Optical Materials

et al. 2015

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120

Promising BP fi eld-effect transistors and absorbers for solar cells have already been demonstrated [ 17,19 ] and proposed. [ 20 ] Apart from the promising applications as transistors or absorbers, the nonlinear response of this 2D semiconductor to applied fi elds is also amazing. The possible nonlinear response properties are determined by the crystalline structure based on the Neumann principle. [ 21 ] Structurally, bulk BP crystals belong to the space group C mca, which indicates that the multilayered BP crystal has a center of inversion and has no second-order nonlinearity, including piezoelectric, ferroelectric, Pockels, second harmonic generation, etc. effects. For the third-order nonlinearity, the saturable absorption of BP has been studied recently and the results pointed out that few-layered BP has a nonlinear response in the visible to mid-infrared range with a large saturable intensity, which is defi ned as the optical intensity at the point where the optical absorption coeffi cient is reduced to half of its original value. In addition to the direct bandgap, which determines the effi cient absorption and emission properties, the optical nonlinearity theoretically indicates that BP should be a potential broadband saturable absorber that can be applied for modulating visible to mid-infrared lasers with large pulse energy. However, up to now, only few BP applications have been demonstrated in 1.5-to 1.9-µm fi ber lasers [22][23][24][25] and there are no reports on their use in bulk lasers either. Here, we report for the fi rst time the experimental realization of a BP pulse modulator and its applications in crystal lasers in the wavelength range of the visible to the mid-infrared. The results widen the spectral range of BP applications and experimentally identify that BP is a promising broadband optical modulator in optics beyond electronics. Results and Discussion Characterization of BP Broadband Modulator and Saturable Absorption MeasurementsThe mechanically exfoliated BP fl akes were investigated by Raman spectroscopy. The Raman shifts after stimulation by a laser with a wavelength of 633 nm are presented in Figure 1 a. From this fi gure, we observe that the peaks appear at 369.2 cm −1 , 439.0 cm −1 , and 467.5 cm −1 , corresponding to one out-of-plane vibration mode A 1 g and two in-plane vibration modes B 2 g and A 2 g , respectively. [ 26,27 ] It is well known that Black phosphorus (BP), a two-dimensional (2D) material, has a direct bandgap that can be tuned by changing the layers and applied strain, which fi lls the lacuna left by graphene topological insulators and transition-metal dichalcogenides. Theoretically, the direct and tunable bandgap should enable broadband applications for optoelectronics with high effi ciencies in the spectral range from the visible to the mid-infrared. Here, a BP broadband optical modulator is experimentally constructed and passively modulated lasers at 639 nm (red), 1.06 µm (near-infrared), and 2.1 µm (mid-infrared) are realized by using a BP optical modulator as the...

Section: Bp Optical Modulation Of Visible To Mid-infrared Lasersmentioning

confidence: 94%

Broadband Black Phosphorus Optical Modulator in the Spectral Range from Visible to Mid‐Infrared

Advanced Optical Materials

et al. 2015

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120

“…On account of the advantages of large pulse energy, short pulse duration, and high peak power, pulse lasers, including mode-locking and Q-switching, receive more widespread attention [2,3]. Pulsed lasers with the pulse width from nanosecond to subpicosecond scales play a key role in the industrial machining, remote sensing, and military defense areas [4].…”

Section: Introductionmentioning

confidence: 99%

“…Pulsed lasers with the pulse width from nanosecond to subpicosecond scales play a key role in the industrial machining, remote sensing, and military defense areas [4]. Ultrashort femtosecond lasers have significant applications in the fields of the in-situ detection, complex reaction dynamics, medical survey, and telecommunication [3]. Passive pulse modulation could be operated with compact and cost-effective structures, such that it has become an influential research direction in the laser field.…”

Section: Introductionmentioning

confidence: 99%

Band-gap modulation of two-dimensional saturable absorbers for solid-state lasers

Wang

2015

Photon. Res.

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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 MoS 2 , vanadium dioxide VO 2 , graphene, and the Bi 2 Se 3 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.

“…This leads to 36(= 3N Z Br ) zone center vibrational degrees of freedom (at k = 0) described by the

D_{4 h}^{19}

‐irreducible representation (see, e.g., Refs. ): Γ 36 = 2A 1g + 4B 1g + B 2g + 5E g + A 2g + B 1u + A 1u + 2B 2u + 4A 2u + 5E u . Amongst them, the first four species (2A 1g + 4B 1g + B 2g + 5E g ), which belong to the internal vibrations of the tetrahedral [VO 4 ] 3− units, are Raman‐active modes.…”

Section: Impulsive Srs Lasingmentioning

confidence: 99%

Impulsive SRS in tetragonal t-YVO₄, t-GdVO₄and monoclinic m-LaVO₄vanadate host-crystals for Ln³⁺-lasant ions

Yoneda

et al. 2016

Phys. Status Solidi B

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Tetragonal t‐YVO4, t‐GdVO4 and monoclinic m‐LaVO4 are widely known as host‐matrix materials for Ln3+‐lasant ions in high‐gain SRS‐active crystals. In this study, many phonon impulsive stimulated Raman scattering (ISRS) was excited under femtosecond pumping for these materials. All of the observed χ(3)‐non‐linear lasing components were attributed to the vibrations of the [VO4]3− structural units of these vanadates. The article gives a short review (in table form) of all known SRS‐active crystals with tetragonal zircon‐type (ZrSiO4) and monazite‐type (CePO4) structure and their observed χ(3)‐nonlinear optical effects.