scholarly journals Manipulation of epsilon-near-zero wavelength for the optimization of linear and nonlinear absorption by supercritical fluid

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiaye Wu ◽  
Xuanyi Liu ◽  
Haishi Fu ◽  
Kuan-Chang Chang ◽  
Shengdong Zhang ◽  
...  
Keyword(s):  
Supercritical Fluid ◽  
Indium Tin Oxide ◽  
Nonlinear Absorption ◽  
Modulation Depth ◽  
Saturable Absorption ◽  
Time Saving ◽  
Nanophotonic Devices ◽  
Absorption Performance ◽  
Linear And Nonlinear ◽  
Epsilon Near Zero

AbstractWe introduce supercritical fluid (SCF) technology to epsilon-near-zero (ENZ) photonics for the first time and experimentally demonstrate the manipulation of the ENZ wavelength for the enhancement of linear and nonlinear optical absorption in ENZ indium tin oxide (ITO) nanolayer. Inspired by the SCF’s applications in repairing defects, reconnecting bonds, introducing dopants, and boosting the performance of microelectronic devices, here, this technique is used to exploit the influence of the electronic properties on optical characteristics. By reducing oxygen vacancies and electron scattering in the SCF oxidation process, the ENZ wavelength is shifted by 23.25 nm, the intrinsic loss is reduced by 20%, and the saturable absorption modulation depth is enhanced by > 30%. The proposed technique offers a time-saving low-temperature technique to optimize the linear and nonlinear absorption performance of plasmonics-based ENZ nanophotonic devices.

Polarization Dependent Nonlinear Absorption in Au Nanowire Array

2014 ◽  
Vol 941-944 ◽  
pp. 483-486
Author(s):  
Ruo Chen Xing ◽  
Si Xiao ◽  
Jun He
Keyword(s):  
Nonlinear Absorption ◽  
Nanowire Array ◽  
Photon Absorption ◽  
Saturable Absorption ◽  
Linear Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Au Nanowire ◽  
Linear And Nonlinear ◽  
Au Nanowires

The polarization dependent nonlinear absorption was observed in ordered Au nanowire array. The linear and nonlinear polarized absorption at 780 nm is investigated by Z-scan. When the angle between the polarization direction of input laser and the long axis of Au nanowires is 90°(perpendicular), the linear absorption reaches the maximum and the nonlinear absorption reaches the minimum. The nonlinear absorption coefficient β decreases from positive to negative as the angle increase from 0° to 90°. There may be two nonlinear absorption mechanisms resulting in this phenomenon: two-photon absorption and saturable absorption in nanoscale.

scholarly journals Nonlinear Optical Properties of Zirconium Diselenide and Its Ultra-Fast Modulator Application

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1419 ◽  
Author(s):  
Wang ◽  
Zheng ◽  
Guo ◽  
Chen ◽  
Zhang ◽  
...  
Keyword(s):  
Nonlinear Absorption ◽  
Modulation Depth ◽  
Ring Cavity ◽  
Maximum Output Power ◽  
Mode Locking ◽  
Saturable Absorption ◽  
Maximum Output ◽  
Transition Metal Dichalcogenide ◽  
Absorption Properties ◽  
Zirconium Diselenide

Recently, two-dimensional (2D) materials have been widely studied by researchers due to their exceptional 2D structure and excellent optical characteristics. As one of the typically-layered 2D transition metal dichalcogenide (TMD) semiconductors from group IVB with a bandgap value of 0.9–1.2 eV (bulk to monolayer), the characteristics of zirconium diselenide (ZrSe2) have already been extensively investigated in many fields. However, the nonlinear absorption properties of ZrSe2 in ultra-fast lasers have not been previously demonstrated. In this work, we measured various parameters in order to investigate the characteristics of the nonlinear saturable absorption of ZrSe2. A ZrSe2–polyvinyl alcohol (PVA) film was successfully prepared, which was employed as a saturable absorber (SA) to demonstrate, for the first time, an erbium (Er)-doped passive mode-locking fiber laser with a ring cavity. The saturation intensity of the ZrSe2–PVA film-type SA is 12.72 MW/cm2, while its modulation depth is 2.3%. The stable soliton state with a maximum output power of 11.37 mW and a narrowest monopulse duration of 12.5 ps at a repetition frequency of 21.22 MHz was detected. The experimental results conclusively proved that ZrSe2, with its suitable bandgap value and excellent nonlinear absorption properties, as well as its high damage threshold, should have extensive potential applications within the field of ultra-fast pulse lasers.

Parallel Directional Coupler based Dual-Polarization Electro-Absorption Modulator using Epsilon Near-Zero Material

2021 ◽  
Author(s):  
Tanmay Bhowmik ◽  
Debabrata Sikdar
Keyword(s):  
Indium Tin Oxide ◽  
High Speed ◽  
Directional Coupler ◽  
Modulation Depth ◽  
Extinction Ratio ◽  
Integrated Photonics ◽  
Dual Polarization ◽  
Active Length ◽  
Te Mode ◽  
Epsilon Near Zero

Abstract Electro–optical modulation, where a radio frequency signal can be encoded in an optical field, is crucial to decide the overall performance of an integrated photonics system. Due to the growing internet penetration rate worldwide, polarization-division-multiplexing (PDM) technique has emerged to increase the link capacity, where polarization-independent modulators are desirable to reduce system complexity. In this study, we propose a novel parallel directional coupler based dual-polarization electro-absorption modulator based on epsilon-near-zero (ENZ) material. The proposed design is capable of independent and synchronized modulation of two fundamental modes viz. transverse magnetic (TM) and transverse electric (TE) mode of a standard silicon rib waveguide. Indium-tin-oxide (ITO)–Silicon based two parallel hybrid plasmonic waveguides (HPW1 and HPW2) are placed such that fundamental TM (TE) mode of the input bus waveguide can be coupled to HPW1 (HPW2). The ENZ-state of ITO, acquired upon two independent electrical gating, enables large modulation depth by utilizing enhancement of electric field at the absorptive carrier accumulation layer. With a 27 μm active length, the extinction ratio (ER) of the proposed design is 10.11 dB (9.66 dB) for TM (TE) modulation at 1550 nm wavelength. This results in a 0.45 dB ER-discrepancy and indicates the polarization-insensitive nature of the modulator. The insertion losses and modulation bandwidths of our design are less than 1 dB and more than 100 GHz, respectively, for both polarizations over the entire C-band of wavelength. The proposed design can find potential applications in the PDM-enabled integrated photonics systems and high speed optical interconnections at data center networks.

Optimization of Reverse Saturable Absorber Limiters: Material Requirements and Design Considerations

1994 ◽  
Vol 374 ◽  
Author(s):  
D. J. Hagan ◽  
T. Xia ◽  
A. Dogariu ◽  
A. A. Said ◽  
E. W. Van Stryland
Keyword(s):  
Nonlinear Absorption ◽  
Entire Length ◽  
Nonlinear Material ◽  
Propagation Path ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Individual Element ◽  
Analytic Model ◽  
Molecular Density ◽  
Optimized Distribution

AbstractWe present numerical beam-propagation simulations of optimized reverse-saturable absorption (RSA) based optical limiters where the depth of focus of the input beam is much smaller than the thickness of the nonlinear material. The optimization is achieved by allowing the molecular concentration to vary along the propagation path, allowing the entire length of the limiter to reach the maximum possible nonlinear absorption before eventual damage to the limiter. We review in detail the analytic model originally derived by Miles [1] to determine the design and performance of such limiters. This model requires the usual 5-level model used in the numerical solution to be approximated by a quasi-three-level system. We show that this effective 3-level excited-state cross section is both pulsewidth and fluence dependent. The numerical propagation output shows that there is considerable diffractive beam distortion, which cannot be accounted for in the analytic model. The end result is that while there is qualitative agreement with numerical results, the magnitude of the limited output can be an order-of-magnitude underestimated. We determine that the fluence level at all parts of the limiter must be at least ten times the saturation fluence to efficiently utilize the nonlinear absorption. We further describe how the optimized distribution of molecular density is the limit of the multi-element tandem limiter for an infinite number of elements. By carefully accounting for saturation over the entire length of each individual element, we show how a multi-element limiter may be designed to closely approach the performance of the optimized distribution for as few as four elements. With current materials technology the damage threshold of solid hosts needed to vary the molecular density is much lower than that of glass cuvettes used for liquid based limiters. Therefore, a multi-element liquid based tandem limiter can be used in full saturation so that better limiter performance should be obtained. Ultimately, however, the operation of all RSA-based limiters involves a strict trade-off between performance and linear transmittance.

scholarly journals Effective Generation of Milliwatt-Level Sub-Terahertz Wave for Nonlinear Response Measurement of Two-Dimensional Material by Optical Heterodyne Technique

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Shuqing Chen ◽  
Zhiqiang Xie ◽  
Junmin Liu ◽  
Yanliang He ◽  
Yao Cai ◽  
...  
Keyword(s):  
Nonlinear Response ◽  
Modulation Depth ◽  
Terahertz Wave ◽  
Saturable Absorption ◽  
Optical Heterodyne ◽  
Two Dimensional ◽  
Response Measurement ◽  
Microwave Source ◽  
Terahertz Band ◽  
Heterodyne Technique

By using optical heterodyne technique, we demonstrated the stable emission of sub-terahertz wave with the frequency ranging from 88 GHz to 101 GHz, which can operate as microwave source for nonlinear response measurement system. Mutual frequency beating of two well-separated sideband signals at a 0.1 THz photo-detector (PD) allows for the generation of sub-terahertz signal. Based on this approach, we have achieved the radiation of 0.1 THz wave with power up to 4 mW. By transmittance measurement, two-dimensional nanomaterial topological insulator (TI: Bi2Te3) shows saturable absorption behaviors with normalized modulation depth of 47% at 0.1 THz. Our results show that optical heterodyne technique could be developed as an effective microwave source generation for nonlinear measurement at sub-terahertz, even terahertz band.

scholarly journals Research on the Response Characteristics of Vanadium Pentoxide Film to the Irradiation of Ultrafast Pulsed Laser

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2078
Author(s):  
Qianqian Shi ◽  
Guodong Zhang ◽  
Yuheng Wang ◽  
Yu Lan ◽  
Jiang Wang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Laser Irradiation ◽  
Vanadium Pentoxide ◽  
Modulation Depth ◽  
Ultrafast Laser ◽  
Stable Phase ◽  
Saturable Absorption ◽  
Third Order ◽  
The Third ◽  
Structural Responses

Vanadium pentoxide (V2O5) is the most stable phase among many transition metal vanadium oxides, and has already been widely used in many fields. In this study, the morphological, structural, and optical responses of V2O5 film to ultrafast laser irradiation was investigated. The third-order nonlinear optical properties of V2O5 film were measured by common Z-scan technique, and the results showed that V2O5 film has self-defocusing and saturable absorption characteristics. The third-order nonlinear absorption coefficient and nonlinear refractive index were calculated to be −338 cm/GW and −3.62 × 10−12 cm2/W, respectively. The tunable saturated absorption with modulation depth ranging from 13.8% to 29.3% was realized through controlling the thickness of vanadium pentoxide film. V2O5 film was irradiated by ultrafast laser with variable pulse energy, and the morphological and structural responses of the V2O5 to the laser with different energy densities were investigated. The irreversible morphological and structural responses of V2O5 films to ultrafast laser irradiation was analyzed using the phase-contrast microscope and Raman spectrum. The chemical structure change from V2O5 to V6O13 was considered the main reason for refractive index modification.

scholarly journals Epsilon-near-zero medium for optical switches in a monolithic waveguide chip at 1.9 μm

Nanophotonics ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 1835-1843 ◽  
Author(s):  
Xiantao Jiang ◽  
Huiling Lu ◽  
Qian Li ◽  
Hang Zhou ◽  
Shengdong Zhang ◽  
...  
Keyword(s):  
Saturable Absorber ◽  
Indium Tin Oxide ◽  
Optical Switches ◽  
Oxide Semiconductor ◽  
Optical Losses ◽  
Average Output ◽  
Stable Mode ◽  
High Modulation ◽  
Cmos Compatible ◽  
Epsilon Near Zero

AbstractA saturable absorber is a building block for integrated ultrafast photonics and passive optical circuits. However, options currently available suffer from the bottlenecks of the necessity for fine control of the material preparation, large optical losses, and compatibility. This paper presents a complementary metal–oxide–semiconductor (CMOS)-compatible alternative based on an epsilon-near-zero (ENZ) medium, in which the real part of the dielectric constant vanishes. Excellent nonlinear optical modulations, including low linear optical losses, low bleaching threshold, moderate optical amplitude modulation, and high modulation speed of indium tin oxide (ITO) in its ENZ region are achieved. The use of ITO as an intracavity saturable absorber for optical switches of integrated waveguide chip lasers at 1.9 μm has been realized. A stable mode-locked waveguide laser with a repetition rate of 6.4 GHz and an average output power of 28.6 mW is achieved via carefully adjusting the intracavity three-surface interferometer (TSI). This work may pave the way for integrated photonics and electro-optics using a CMOS-compatible ENZ medium.

Passively mode-locked in Er-doped fiber laser based on semi-metallic InBi saturable absorber

2021 ◽  
Author(s):  
Jianwei Hu ◽  
Rong Huang ◽  
Ziqiao Wei ◽  
Minru Wen ◽  
Fugen Wu ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Modulation Depth ◽  
Mode Locking ◽  
Nodal Line ◽  
Saturable Absorption ◽  
Optical Nonlinearities ◽  
Passive Mode ◽  
Central Wavelength ◽  
Two Dimensional Materials ◽  
Er Doped

Abstract Two-dimensional materials have drawn great interest for their applications in mode-locking owning to their unique optical nonlinearities. However, most of these 2D materials are semi-conductor. In this study, a new kind of semimetal Indium bismuth (InBi) is reported which is a topological nodal-line semimetal with exotic physical properties. The InBi nanomaterials was prepared through liquid phase exfoliation method with average thickness of 32.8 nm. The saturable absorption property was measured and passive mode-locking operation was achieved successfully in Er-doped fiber laser. It exhibits a modulation depth of 3.21%, a saturable intensity of 100 MW/cm2, and a pulse width about 859.97 fs corresponding to the central wavelength of 1562.27 nm and 3-dB bandwidth of 2.98 nm. The experimental results open a new avenue for the use of semimetals InBi nanomaterials in lasers and photonics applications.

Sign in / Sign up

Export Citation Format

Share Document