Recent Advances in Nonlinear Optics and Nonlinear Optical Materials

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Sciences applsci	2.5	5.3	2011	18.4 Days	CHF 2400
Fibers fibers	4.0	7.0	2013	21.3 Days	CHF 2000
Micromachines micromachines	3.0	5.2	2010	16.2 Days	CHF 2100
Molecules molecules	4.2	7.4	1996	15.1 Days	CHF 2700
Photonics photonics	2.1	2.6	2014	14.9 Days	CHF 2400

11 pages, 4949 KiB

Open AccessEditor’s ChoiceArticle

The Generation of Circularly Polarized Isolated Attosecond Pulses with Tunable Helicity from CO Molecules in Polarization Gating Laser Fields

by Shiju Chen, Hua Yuan, Feng Wang, Jiahang Song, Yue Zhao, Chunhui Yang, Tianxin Ou, Ru Zhang, Qiang Chang and Yuping Sun

Photonics 2024, 11(5), 464; https://doi.org/10.3390/photonics11050464 - 15 May 2024

Viewed by 1571

Abstract

We theoretically demonstrate a scheme to generate circularly polarized (CP) isolated attosecond pulses (IAPs) with tunable helicity using a polarization gating laser field interacting with the CO molecule. The results show that a broadband CP supercontinuum is produced from the oriented CO molecule, [...] Read more.

We theoretically demonstrate a scheme to generate circularly polarized (CP) isolated attosecond pulses (IAPs) with tunable helicity using a polarization gating laser field interacting with the CO molecule. The results show that a broadband CP supercontinuum is produced from the oriented CO molecule, which supports the generation of an IAP with an ellipticity of 0.98 and a duration of 90 as. Furthermore, the helicity of the generated harmonics and IAP can be effectively controlled by modulating the laser field and the orientation angle of the CO molecule. Our method will advance research on chiral-specific dynamics and magnetic circular dichroism on the attosecond timescale. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)

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12 pages, 3101 KiB

Open AccessArticle

Protecting the Quantum Coherence of Two Atoms Inside an Optical Cavity by Quantum Feedback Control Combined with Noise-Assisted Preparation

by Chang-Xiao Li

Photonics 2024, 11(5), 400; https://doi.org/10.3390/photonics11050400 - 25 Apr 2024

Cited by 3 | Viewed by 1162

Abstract

We propose a theoretical scheme to enhance quantum coherence and obtain steady-state coherence by combining quantum feedback control and noise-assisted preparation. We investigate the effects of quantum-jump-based feedback control and noise field on the quantum coherence and excited-state population between two atoms inside [...] Read more.

We propose a theoretical scheme to enhance quantum coherence and obtain steady-state coherence by combining quantum feedback control and noise-assisted preparation. We investigate the effects of quantum-jump-based feedback control and noise field on the quantum coherence and excited-state population between two atoms inside an optical cavity where a noise field drives one, and the other is under quantum feedback control. It is found that steady quantum coherence can be achieved by adding an external noise field, and the quantum feedback can prolong the coherence time with partial suppression of the spontaneous emission of atoms. In addition, we study the influence of the joint action of quantum feedback and noise-assisted preparation on quantum coherence and show that the combined action of feedback control and noise-assisted preparation is more effective in enhancing steady coherence. The findings of our research offer some general guidelines for improving the steady-state coherence of coupled qubit systems and have the potential to be applied in the realm of quantum information technology. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)

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11 pages, 22486 KiB

Open AccessArticle

Enhancement of Broadband Reverse Saturable Absorption of Red/Black Phosphorus Heterojunction

by Jingjing Wang, Fulai Liu, Yunfei Li, Long Chen, Yong Chen, Hailong Zhang and Zheng Xie

Molecules 2024, 29(6), 1271; https://doi.org/10.3390/molecules29061271 - 13 Mar 2024

Cited by 1 | Viewed by 1474

Abstract

Although laser technology brings convenience to production and daily life, it also causes high-energy damage. Therefore, there is an urgent need to develop optical limiting materials for laser protection. In this study, a novel nonlinear optical material, red/black phosphorus lateral heterojunction, is successfully [...] Read more.

Although laser technology brings convenience to production and daily life, it also causes high-energy damage. Therefore, there is an urgent need to develop optical limiting materials for laser protection. In this study, a novel nonlinear optical material, red/black phosphorus lateral heterojunction, is successfully prepared through solvothermal and ultrasonic treatment. Using the Z−scan method, the nonlinear optical properties of the red/black phosphorus heterojunction are determined at wavelengths of 532 and 1064 nm. These results indicate that the red/black phosphorus heterojunction exhibits reverse saturable absorption properties in 1.2.3-glycerol. Interestingly, the red/black phosphorus heterojunction shows an enhanced performance over red phosphorus by introducing the black phosphorus phase. Moreover, the red/black phosphorus heterojunction is doped into organically modified silicate gel glass with excellent broadband optical limiting performance. This study highlights the promising prospect of the red/black phosphorus heterojunction in the nonlinear optical and optical limiting fields. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)

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10 pages, 3242 KiB

Open AccessArticle

Slot-Waveguide Based All-Optical RF Spectrum Analyzer

by Yuhua Li, Zhe Kang, Wai-Lok Ho, Roy R. Davidson, Brent E. Little, Sai-Tak Chu and Kun Zhu

Photonics 2023, 10(12), 1380; https://doi.org/10.3390/photonics10121380 - 15 Dec 2023

Viewed by 1689

Abstract

All-optical radio-frequency spectrum analyzers (AORFSAs) with ultrabroad bandwidth break the electronic bottleneck and provide an efficient frequency analysis means for ultrafast optical signals in communications, signal generation and processing systems. Here, we propose and experimentally demonstrate an AORFSA built on the cross-phase modulation [...] Read more.

All-optical radio-frequency spectrum analyzers (AORFSAs) with ultrabroad bandwidth break the electronic bottleneck and provide an efficient frequency analysis means for ultrafast optical signals in communications, signal generation and processing systems. Here, we propose and experimentally demonstrate an AORFSA built on the cross-phase modulation effect in a 50 cm long CMOS-compatible photonic slot-waveguide. The waveguide has a 100 nm thick thin-film core of fused silica that is sandwiched by two 750 nm thick cladding layers of high-index doped silica, which shows optimized dispersion and comparable nonlinear characteristics. The measured 3 dB bandwidth of the proposed slot-waveguide-based AORFSA has a three-fold increase over the conventional channel waveguide having the same dimension and length. The sensitivity and wavelength- and polarization-dependence properties are investigated, confirming the proposed waveguide as a versatile platform for frequency analysis of ultrafast optical signals, such as Kerr microcombs with hundreds of GHz or even THz mode spacing. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)

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14 pages, 4780 KiB

Open AccessArticle

Cascaded Stimulated Polariton Scattering in a Single-Pass KTP Crystal under Picosecond Pumping

by Konstantin A. Vereshchagin, Alexey K. Vereshchagin, Vyacheslav B. Morozov and Vladimir G. Tunkin

Photonics 2023, 10(12), 1355; https://doi.org/10.3390/photonics10121355 - 8 Dec 2023

Viewed by 1391

Abstract

Cascaded stimulated polariton scattering (SPS) under powerful picosecond pumping of 532 nm wavelength was investigated in a single pass of a KTP (KTiOPO₄) crystal. Under ordinary polarization of the pump wave (relatively XOZ-plane) parametric scattering in the KTP crystal was [...] Read more.

Cascaded stimulated polariton scattering (SPS) under powerful picosecond pumping of 532 nm wavelength was investigated in a single pass of a KTP (KTiOPO₄) crystal. Under ordinary polarization of the pump wave (relatively XOZ-plane) parametric scattering in the KTP crystal was observed. By rotation of the pump wave polarization (from ordinary to extraordinary), this scattering gradually transforms into polariton scattering. Polariton signal components (spots) with gaps between them were registered at external angles of ~2° between the neighboring spots. Five polariton signal components were detected above the pump beam, with a frequency difference between neighboring cascaded components of ~188 cm⁻¹ (5.64 THz). The wavelength of each next component increased regularly with the angle between this component and the pump wave, so this regular sequence of polariton signal components can be regarded as a cascaded SPS. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)

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12 pages, 745 KiB

Open AccessArticle

Valley-Selective High Harmonic Generation and Polarization Induced by an Orthogonal Two-Color Laser Field

by Xi Liu, Dongdong Liu, Yan Sun, Yujie Li and Cui Zhang

Photonics 2023, 10(10), 1126; https://doi.org/10.3390/photonics10101126 - 8 Oct 2023

Cited by 7 | Viewed by 1630

Abstract

The valley pseudospin properties of electrons in two-dimensional hexagonal materials result in many fascinating physical phenomena, which opens up the new field of valleytronics. The valley-contrasting physics aims at distinguishing the valley degree of freedom based on valley-dependent effects. Here, we theoretically demonstrate [...] Read more.

The valley pseudospin properties of electrons in two-dimensional hexagonal materials result in many fascinating physical phenomena, which opens up the new field of valleytronics. The valley-contrasting physics aims at distinguishing the valley degree of freedom based on valley-dependent effects. Here, we theoretically demonstrate that both of the valley-selective high harmonic generation and valley-selective electronic excitation can be achieved by using an orthogonal two-color (OTC) laser field in gapped graphene. It is shown that the asymmetry degrees of harmonic yields in the plateaus, cutoff energies of generated harmonics and electron populations from two different valleys can be precisely controlled by the relative phase of the OTC laser field. Thus, the selectivity of the dominant valley for the harmonic radiation and electronic polarization can be switched by adjusting the relative phase of the OTC laser field. Our work offers an all-optical route to produce the valley-resolved high harmonic emissions and manipulate the ultrafast valley polarization on a femtosecond timescale in condensed matter. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)

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11 pages, 9648 KiB

Open AccessArticle

Siloxene Nanosheets and Their Hybrid Gel Glasses for Broad-Band Optical Limiting

by Xugui Lv, Nan Li, Yunfei Li, Qingyu Ma, Zheng Xie and Shuyun Zhou

Molecules 2023, 28(5), 2143; https://doi.org/10.3390/molecules28052143 - 24 Feb 2023

Cited by 4 | Viewed by 2239

Abstract

With the development of laser technology, the research of novel laser protection materials is of great significance. In this work, dispersible siloxene nanosheets (SiNSs) with a thickness of about 1.5 nm are prepared by the top-down topological reaction method. Based on the Z-scan [...] Read more.

With the development of laser technology, the research of novel laser protection materials is of great significance. In this work, dispersible siloxene nanosheets (SiNSs) with a thickness of about 1.5 nm are prepared by the top-down topological reaction method. Based on the Z-scan and optical limiting testing under the visible-near IR ranges nanosecond laser, the broad-band nonlinear optical properties of the SiNSs and their hybrid gel glasses are investigated. The results show that the SiNSs have outstanding nonlinear optical properties. Meanwhile, the SiNSs hybrid gel glasses also exhibit high transmittance and excellent optical limiting capabilities. It demonstrates that SiNSs are promising materials for broad-band nonlinear optical limiting and even have potential applications in optoelectronics. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)
(This article belongs to the Section Materials Chemistry)

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12 pages, 2632 KiB

Open AccessArticle

Synthesis, Photoswitching Behavior and Nonlinear Optical Properties of Substituted Tribenzo[a,d,g]coronene

by Xueqing Li, Jie Zhao, Wei Wang, Yiming Li, Yunfei Li, Shuyun Zhou and Jinchong Xiao

Molecules 2023, 28(3), 1419; https://doi.org/10.3390/molecules28031419 - 2 Feb 2023

Cited by 3 | Viewed by 2226

Abstract

A family of tribenzocoronene derivatives bearing various substituents (3) were constructed through the Diels–Alder reaction, followed by the Scholl oxidation, where the molecular structure of 3b was determined via single crystal X-ray diffraction analysis. The effect of substitution on the optical [...] Read more.

A family of tribenzocoronene derivatives bearing various substituents (3) were constructed through the Diels–Alder reaction, followed by the Scholl oxidation, where the molecular structure of 3b was determined via single crystal X-ray diffraction analysis. The effect of substitution on the optical and electrochemical property was systematically investigated, with the assistance of theoretical calculations. Moreover, the thin films of the resulting molecules 3b and 3e complexed with fullerene produced strong photocurrent response upon irradiation of white light. In addition, 3b and 3e exhibit a positive nonlinear optical response resulting from the two-photon absorption and excited state absorption processes. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)
(This article belongs to the Section Materials Chemistry)

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11 pages, 1333 KiB

Open AccessArticle

The Kurtz–Perry Powder Technique Revisited: A Study of the Effect of Reference Selection on Powder Second-Harmonic Generation Response

by Mengran Sun, Guili Wang and Jiyong Yao

Molecules 2023, 28(3), 1116; https://doi.org/10.3390/molecules28031116 - 22 Jan 2023

Cited by 5 | Viewed by 3410

Abstract

The accurate evaluation of nonlinear optical (NLO) coefficient, the main parameter affecting light conversion efficiency, plays a crucial role in the development of NLO materials. The Kurtz–Perry powder technique can evaluate second-harmonic generation (SHG) intensity in pristine powder form, saving a significant amount [...] Read more.

The accurate evaluation of nonlinear optical (NLO) coefficient, the main parameter affecting light conversion efficiency, plays a crucial role in the development of NLO materials. The Kurtz–Perry powder technique can evaluate second-harmonic generation (SHG) intensity in pristine powder form, saving a significant amount of time and energy in the preliminary screening of materials. However, the Kurtz–Perry method has recently been subject to some controversy due to the limitations of the Kurtz–Perry theory and the oversimplified experimental operation. Therefore, it is very meaningful to revisit and develop the Kurtz–Perry technique. In this work, on the basis of introducing the light scattering effect into the original Kurtz–Perry theory, the theoretical expression of second-harmonic generation intensity with respect to band gap and refractive index are analyzed. In addition, the reference-dependent SHG measurements were carried out on polycrystalline LiB₃O₅ (LBO), AgGaQ₂ (Q = S, Se), BaGa₄Q₇ (Q = S, Se), and ZnGeP₂ (ZGP), and the results of SHG response emphasize the importance of using appropriate references to the Kurtz–Perry method. In order to obtain reliable values of nonlinear coefficients, two criteria for selecting a reference compound were proposed: (1) it should possess a band gap close to that of the sample to be measured and (2) it should possess a refractive index close to that of the sample to be measured. This work might shed light on improvements in accuracy that can be made for effective NLO coefficients obtained using the Kurtz–Perry method. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)
(This article belongs to the Section Materials Chemistry)

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12 pages, 156260 KiB

Open AccessArticle

Synthesis, Photophysics and Tunable Reverse Saturable Absorption of Bis-Tridentate Iridium(III) Complexes via Modification on Diimine Ligand

by Guochang Li, Zhao Jiang, Meng Tang, Xiaoli Jiang, Houfu Tu, Senqiang Zhu, Rui Liu and Hongjun Zhu

Molecules 2023, 28(2), 566; https://doi.org/10.3390/molecules28020566 - 5 Jan 2023

Cited by 7 | Viewed by 2228

Abstract

Five novel bis-tridentate Ir(III) complexes (Ir-1–Ir-5) incorporating versatile N^N^C ligands and a N^C^N ligand (1,3-di(2-pyridyl)-4,6-dimethylbenzene) were synthesized. With the combination of experimental and theoretical methods, their steady and transient state characteristics were researched scientifically. The UV-visible absorption spectra show [...] Read more.

Five novel bis-tridentate Ir(III) complexes (Ir-1–Ir-5) incorporating versatile N^N^C ligands and a N^C^N ligand (1,3-di(2-pyridyl)-4,6-dimethylbenzene) were synthesized. With the combination of experimental and theoretical methods, their steady and transient state characteristics were researched scientifically. The UV-visible absorption spectra show that the broadband charge transfer absorbance of those bis-tridentate Ir(III) complexes can reach 550 nm, all of these complexes reveal the long-lasting phosphorescent emission. Because the excited-state absorption is more powerful than the ground-state absorption, a sturdy reverse saturable absorption (RSA) process can ensue in the visible and near-infrared regions when the complexes are exposed to a 532 nm laser. Therefore, the optical power limiting (OPL) effect follows the trend: Ir-5 > Ir-4 ≈ Ir-3 > Ir-2 > Ir-1. Generally speaking, the expansion of π-conjugation and the introduction of electron donating/withdrawing groups on the N^N^C ligand could effectively elevate the OPL effect. Therefore, these octahedral bis-tridentate Ir(III) complexes might be exploited as potential OPL materials. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)
(This article belongs to the Section Materials Chemistry)

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14 pages, 1571 KiB

Open AccessArticle

Systematic Study on Nonlinear Optical Chromophores with Improved Electro-Optic Activity by Introducing 3,5-Bis(trifluoromethyl)benzene Derivative Isolation Groups into the Bridge

by Tongtong Liu, Fuyang Huo, Changqing Ge, Ya Li, Jing He, Han Zheng, Qian He, Yinsen Zhao, Zhuo Chen and Shuhui Bo

Molecules 2023, 28(2), 488; https://doi.org/10.3390/molecules28020488 - 4 Jan 2023

Cited by 3 | Viewed by 2347

Abstract

A series of novel chromophores A, B, C, and D, based on the julolidinyl donor and the tricyanofuran (TCF) and CF₃-tricyanofuran (CF₃-Ph-TCF) acceptors, have been synthesized and systematically investigated. The 3,5-bis(trifluoromethyl)benzene derivative isolation group was introduced into the [...] Read more.

A series of novel chromophores A, B, C, and D, based on the julolidinyl donor and the tricyanofuran (TCF) and CF₃-tricyanofuran (CF₃-Ph-TCF) acceptors, have been synthesized and systematically investigated. The 3,5-bis(trifluoromethyl)benzene derivative isolation group was introduced into the bridge in the chromophores C and D. These nonlinear optical chromophores showed good thermal stability, and their decomposition temperatures were all above 220 °C. Density functional theory (DFT) was used to calculate the energy gaps and first-order hyperpolarizability (

β

). The macroscopic electro-optic (EO) activity was measured using a simple reflection method. The highest EO coefficient of poled films containing 35 wt% of chromophore D doped in amorphous polycarbonate afforded values of 54 pm/V at 1310 nm. The results indicate that the 3,5-bis(trifluoromethyl)benzene isolation group can suppress the dipole–dipole interaction of chromophores. The moderate

r_{33}

value, good thermal stability, and good yield of chromophores suggest their potential use in the nonlinear optical area. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)
(This article belongs to the Section Materials Chemistry)

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12 pages, 3985 KiB

Open AccessArticle

Enhanced Ultrafast Broadband Reverse Saturable Absorption in Twistacenes with Enlarged π-Conjugated Central Bridge

by Xindi Liu, Wenfa Zhou, Mengyi Wang, Xingzhi Wu, Jidong Jia, Jinchong Xiao, Junyi Yang and Yinglin Song

Molecules 2022, 27(24), 9059; https://doi.org/10.3390/molecules27249059 - 19 Dec 2022

Cited by 2 | Viewed by 2010

Abstract

Optical nonlinearities of two all-carbon twistacenes, DPyA and DPyN, with the different π-conjugated central bridges were investigated. The nonlinear absorption properties of these compounds were measured using the femtosecond Z-scan with wavelengths between 650 and 900 nm. It has been found that [...] Read more.

Optical nonlinearities of two all-carbon twistacenes, DPyA and DPyN, with the different π-conjugated central bridges were investigated. The nonlinear absorption properties of these compounds were measured using the femtosecond Z-scan with wavelengths between 650 and 900 nm. It has been found that the nonlinear absorption originated from two-photon absorption (TPA) and TPA-induced excited state absorption (ESA), wherein DPyA demonstrates higher performance than DPyN. The TPA cross section of DPyA (4300 GM) is nearly 4.3 times larger than that of DPyN at 650 nm. Moreover, the different central structures modulate the intensity of ESA at 532 nm, and DPyA exhibits an excellent ESA at 532 nm with multi-pulse excitation. Meanwhile, the result of data fitting and quantum chemistry calculation shows that the enhancement of nonlinear absorption in DPyA is due to the extended π- conjugated bridge and improved delocalization of π-electrons. These all-carbon twistacenes could yield potential applications in optical power limiting (OPL) technology. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)
(This article belongs to the Section Materials Chemistry)

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12 pages, 2344 KiB

Open AccessArticle

Synthesis and Ultrafast Broadband Optical Limiting Properties of a Two-Branched Twistacene

by Yanbing Han, Jinchong Xiao, Xingzhi Wu, Yuxiao Wang, Xueru Zhang and Yinglin Song

Molecules 2022, 27(11), 3564; https://doi.org/10.3390/molecules27113564 - 1 Jun 2022

Cited by 9 | Viewed by 1922

Abstract

A novel two-branched twistacene (PyDN) has been designed and synthesized for application on ultrafast optical limiting. This twistacene exhibits excellent two photon absorption and two photon absorption-induced excited singlet state absorption, which was systematically investigated with a femtosecond Z-scan experiment, transient [...] Read more.

A novel two-branched twistacene (PyDN) has been designed and synthesized for application on ultrafast optical limiting. This twistacene exhibits excellent two photon absorption and two photon absorption-induced excited singlet state absorption, which was systematically investigated with a femtosecond Z-scan experiment, transient absorption spectrum, and two-photon excited fluorescence experiments. The admirable two photon absorption is attributed to the high degree of π electron delocalization in twistacene which is caused by introduction of two strong donors. The excited singlet state absorption cooperates with two-photon absorption to provide an excellent ultrafast optical limiting behavior with high linear transmittance, where the thresholds are 2.3–5.3 mJ/cm² in the spectral region of 532–800 nm of femtosecond laser and 133 mJ/cm² for picosecond pulse at 532 nm. These thresholds are lower than that of most of the optical limiters reported previously, which indicates PyDN is a promising candidate for ultrafast optical limiting. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)
(This article belongs to the Section Materials Chemistry)

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12 pages, 5179 KiB

Open AccessArticle

Enhancement of Two-Photon Absorption in Boron-Dipyrromethene (BODIPY) Derivatives

by Guanzheng Song, Zhongguo Li, Yanbing Han, Jidong Jia, Wenfa Zhou, Xueru Zhang, Yuxiao Wang and Yinglin Song

Molecules 2022, 27(9), 2849; https://doi.org/10.3390/molecules27092849 - 29 Apr 2022

Cited by 6 | Viewed by 2332

Abstract

The linear and nonlinear optical properties of two BODIPY derivatives, 1,7-Diphenyl-3,5-bis(9,9-dimethyl-9H-fluoren-2-yl)-boron-diuoride-azadipyrromethene (ZL-61) and 1,7-Diphenyl-3,5-bis(4-(1,2,2-triphenylvinyl)phenyl)-boron-diuoride-azadipyrromethene (ZL-22), were comprehensively investigated based on experimental and theoretical studies. It was found that both compounds show a strong two-photon absorption response in the near-infrared regime, and the two-photon-absorption [...] Read more.

The linear and nonlinear optical properties of two BODIPY derivatives, 1,7-Diphenyl-3,5-bis(9,9-dimethyl-9H-fluoren-2-yl)-boron-diuoride-azadipyrromethene (ZL-61) and 1,7-Diphenyl-3,5-bis(4-(1,2,2-triphenylvinyl)phenyl)-boron-diuoride-azadipyrromethene (ZL-22), were comprehensively investigated based on experimental and theoretical studies. It was found that both compounds show a strong two-photon absorption response in the near-infrared regime, and the two-photon-absorption cross-section values of ZL-61 and ZL-22 were determined to be 8321 GM and 1864 GM at 800 nm, respectively. The improvement of the two-photon absorption cross section in ZL-61 was attributed to the enhancement of the donor group, which was confirmed by transient absorption measurements and DFT calculation. Our results indicate that these BODIPY derivatives are a promising candidate for optical limiting and two-photon imaging applications. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)
(This article belongs to the Section Materials Chemistry)

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7 pages, 1788 KiB

Open AccessArticle

Size-Dependent Nonlinear Optical Properties of Gd₂O₂S:Tb³⁺ Scintillators and Their Doped Gel Glasses

by Long Chen, Cuiyu Wu, Zheng Xie, Chenghua Sun and Shuyun Zhou

Molecules 2022, 27(1), 85; https://doi.org/10.3390/molecules27010085 - 24 Dec 2021

Cited by 5 | Viewed by 2870

Abstract

With the advancement of ultra-fast and high-energy pulsed laser output, lasers have caused serious harm to precision instruments and human eyes. Therefore, the development of optical limiting materials with a fast response, low optical limiting threshold, and high damage threshold are important. In [...] Read more.

With the advancement of ultra-fast and high-energy pulsed laser output, lasers have caused serious harm to precision instruments and human eyes. Therefore, the development of optical limiting materials with a fast response, low optical limiting threshold, and high damage threshold are important. In this work, for the first time, it is reported that phosphors Gd₂O₂S:Tb³⁺(GOS) displays exceptional functionality in laser protection. GOS with sizes of 11 μm, 1 μm, and 0.45 μm are prepared. Based on the optical limiting and Z-scan technology systems under 532 nm and 1064 nm nanosecond laser excitation, the nonlinear optical properties of GOS are investigated. It is found that GOS exhibits outstanding optical limiting properties. In addition, the optical limiting response of GOS is size-dependent. Concerning the largest particle size, GOS has the best nonlinear optical response, while the precursor shows no nonlinear optical performance. Meanwhile, GOS doped gel glass also displays excellent optical limiting properties with high transmittance, which preliminarily validates the application of GOS and other scintillators in nonlinear optics and encourages more research to better realize the potential of GOS. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)
(This article belongs to the Section Materials Chemistry)

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9 pages, 4975 KiB

Open AccessArticle

First-Principles Study of Bi-Doping Effects in Hg_0.75Cd_0.25Te

by Xueli Sun, Xuejun Su, Dechun Li and Lihua Cao

Molecules 2021, 26(16), 4847; https://doi.org/10.3390/molecules26164847 - 11 Aug 2021

Viewed by 2131

Abstract

First-principles calculations based on density functional theory have been performed for exploring the structural and electronic properties of Bi-doped Hg_0.75Cd_0.25Te (MCT), using the state-of-the-art computational method with the Heyd–Scuseria–Ernzerhof (HSE) of hybrid functional to correct the band gap. Structural [...] Read more.

First-principles calculations based on density functional theory have been performed for exploring the structural and electronic properties of Bi-doped Hg_0.75Cd_0.25Te (MCT), using the state-of-the-art computational method with the Heyd–Scuseria–Ernzerhof (HSE) of hybrid functional to correct the band gap. Structural relaxations, charge densities, electron localization functions (ELFs), density of states (DOSs), band structures, and band decomposed charge density were obtained to reveal the amphoteric behavior of Bi in Hg_0.75Cd_0.25Te. The bonding characteristics between Bi and host atoms were discussed by analyzing charge densities and ELFs. The influence of Bi impurity on the electronic structure of Bi-doped Hg_0.75Cd_0.25Te was also analyzed by the calculated DOSs, band structures, and the band decomposed charge density of the defect band. It has been demonstrated that Bi can show a typical amphoteric substitution effect of group V elements. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)
(This article belongs to the Section Materials Chemistry)

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11 pages, 2104 KiB

Open AccessArticle

Generation of High Peak Power Mode-Locked Green Pulses Based on WS₂ and EOM: Experiment and Theory

by Wenjing Tang, Wanggen Sun, Jing Wang, Kai Jiang, Wei Xia and Shengzhi Zhao

Molecules 2021, 26(15), 4406; https://doi.org/10.3390/molecules26154406 - 21 Jul 2021

Cited by 1 | Viewed by 2046

Abstract

Based on an as-prepared high-quality WS₂ film and an electro-optic modulator (EOM), a dual-loss-modulated low repetition rate mode-locking laser at 0.53 μm with high peak power is presented for the first time. The laser characteristics versus the pump power are investigated experimentally [...] Read more.

Based on an as-prepared high-quality WS₂ film and an electro-optic modulator (EOM), a dual-loss-modulated low repetition rate mode-locking laser at 0.53 μm with high peak power is presented for the first time. The laser characteristics versus the pump power are investigated experimentally and theoretically. At a pump power of 10.67 W, the shortest pulse duration of 305 ps can be measured, corresponding to the highest peak power of 931 kW, which is much higher than those of the single passive modulated lasers with WS₂-SA. A simple rate equation simulation was used to describe this dual-loss-modulated mode-locking green laser based on WS₂ and EOM. The results of the numerical simulation are basically in accordance with the experimental values. Full article

(This article belongs to the Topic Recent Advances in Nonlinear Optics and Nonlinear Optical Materials)
(This article belongs to the Section Materials Chemistry)

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