37 research outputs found
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Miniaturization of optical spectrometers
Spectroscopic analysis is one of the most widely used analytical tools across both scientific research and industry. Whilst laboratory bench-top spectrometer systems offer superlative resolution and spectral range, their miniaturization is crucial for applications where portability is paramount, or in-situ measurements must be made. Advancement in this field over the last three decades is now yielding microspectrometers with performance and footprint near those viable for lab-on-a-chip systems, smartphones and other consumer technologies. In this review, we briefly summarize the technologies that have emerged toward achieving these aims - including miniaturized dispersive optics, narrowband filter systems, Fourier transform interferometers and reconstructive microspectrometers - and discuss the challenges associated with improving spectral resolution while device dimensions shrink ever further.EPSRC: EP/L016087/1
National Natural Science Foundation of China (51706141, 51976122
Functional inks of graphene, metal dichalcogenides and black phosphorus for photonics and (opto) electronics
We discuss the emerging role of solution processing and functional ink formulation in the fabrication of devices
based on two dimensional (2d) materials. By drawing on examples from our research, we show that these inks
allow 2d materials to be exploited in a wide variety of applications, including in photonics and (opto)electronics.
Keywords: Graphene, Transition Metal Dichalcogenides, TMDs, Black Phosphorous, Phosphorene, Functional
Inks, 2d Materials, Inkjet Printing, Ultrafast Lasers, Flexible Electronic
Surfactant-aided exfoliation of molydenum disulphide for ultrafast pulse generation through edge-state saturable absorption
We use liquid phase exfoliation to produce dispersions of molybdenum
disulphide (MoS2) nanoflakes in aqueous surfactant solutions. The chemical
structures of the bile salt surfactants play a crucial role in the exfoliation
and stabilization of MoS2. The resultant MoS2 dispersions are heavily enriched
in single and few (<6) layer flakes with large edge to surface area ratio. We
use the dispersions to fabricate free-standing polymer composite wide-band
saturable absorbers to develop mode-locked and Q- switched fibre lasers,
tunable from 1535-1565 and 1030-1070 nm, respectively. We attribute this
sub-bandgap optical absorption and its nonlinear saturation behaviour to
edge-mediated states introduced within the material band-gap of the exfoliated
MoS2 nanoflakes.Comment: 6 pages, 5 figure
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On-nanowire spatial band gap design for white light emission.
This is the accepted manuscript. The final version is available from ACS at http://pubs.acs.org/doi/abs/10.1021/nl203529h.We demonstrated a substrate-moving vapor-liquid-solid (VLS) route for growing composition gradient ZnCdSSe alloy nanowires. Relying on temperature-selected composition deposition along their lengths, single tricolor ZnCdSSe alloy nanowires with engineerable band gap covering the entire visible range were obtained. The photometric property of these tricolor nanowires, which was determined by blue-, green-, and red-color emission intensities, can be in turn controlled by their corresponding emission lengths. More particularly, under carefully selected growth conditions, on-nanowire white light emission has been achieved. Band-gap-engineered semiconductor alloy nanowires demonstrated here may find applications in broad band light absorption and emission devices
Miniaturized Computational Photonic Molecule Spectrometer
Miniaturized spectrometry system is playing an essential role for materials
analysis in the development of in-situ or portable sensing platforms across
research and industry. However, there unavoidably exists trade-offs between the
resolution and operation bandwidth as the device scale down. Here, we report an
extreme miniaturized computational photonic molecule (PM) spectrometer
utilizing the diverse spectral characteristics and mode-hybridization effect of
split eigenfrequencies and super-modes, which effectively eliminates the
inherent periodicity and expands operation bandwidth with ultra-high spectral
resolution. These results of dynamic control of the frequency, amplitude, and
phase of photons in the photonic multi-atomic systems, pave the way to the
development of benchtop sensing platforms for applications previously
unfeasible due to resolution-bandwidth-footprint limitations, such as in gas
sensing or nanoscale biomedical sensing
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Enhancing monolayer photoluminescence on optical micro/nanofibers for low-threshold lasing.
Although monolayer transition metal dichalcogenides (TMDs) have direct bandgaps, the low room-temperature photoluminescence quantum yields (QYs), especially under high pump intensity, limit their practical applications. Here, we use a simple photoactivation method to enhance the room-temperature QYs of monolayer MoS2 grown on to silica micro/nanofibers by more than two orders of magnitude in a wide pump dynamic range. The high-density oxygen dangling bonds released from the tapered micro/nanofiber surface are the key to this strong enhancement of QYs. As the pump intensity increases from 10-1 to 104 W cm-2, our photoactivated monolayer MoS2 exhibits QYs from ~30 to 1% while maintaining high environmental stability, allowing direct lasing with greatly reduced thresholds down to 5 W cm-2. Our strategy can be extended to other TMDs and offers a solution to the most challenging problem toward the realization of efficient and stable light emitters at room temperature based on these atomically thin materials
Single-nanowire spectrometers.
Spectrometers with ever-smaller footprints are sought after for a wide range of applications in which minimized size and weight are paramount, including emerging in situ characterization techniques. We report on an ultracompact microspectrometer design based on a single compositionally engineered nanowire. This platform is independent of the complex optical components or cavities that tend to constrain further miniaturization of current systems. We show that incident spectra can be computationally reconstructed from the different spectral response functions and measured photocurrents along the length of the nanowire. Our devices are capable of accurate, visible-range monochromatic and broadband light reconstruction, as well as spectral imaging from centimeter-scale focal planes down to lensless, single-cell-scale in situ mapping.EPSRC (EP/M013812/1, EP/L016087/1), the Royal Commission for the Exhibition of 1851, CRUK Pioneer Award (C55962/A24669), , Business Finland (A-Photonics), Academy of Finland, ERC (834742), EU Horizon 2020 (820423), the Cambridge Trust, the Royal Society
Plasmon-driven nanowire actuators for on-chip manipulation.
Funder: National Natural Science Foundation of China (11674230); Shanghai Rising-Star Program (18QA1403200)Chemically synthesized metal nanowires are promising building blocks for next-generation photonic integrated circuits, but technological implementation in monolithic integration will be severely hampered by the lack of controllable and precise manipulation approaches, due to the strong adhesion of nanowires to substrates in non-liquid environments. Here, we demonstrate this obstacle can be removed by our proposed earthworm-like peristaltic crawling motion mechanism, based on the synergistic expansion, friction, and contraction in plasmon-driven metal nanowires in non-liquid environments. The evanescently excited surface plasmon greatly enhances theĀ heating effect in metal nanowires, thereby generating surface acoustic waves to drive the nanowires crawling along silica microfibres. Advantages include sub-nanometer positioning accuracy, low actuation power, and self-parallel parking. We further demonstrate on-chip manipulations including transporting, positioning, orientation, and sorting, with on-situ operation, high selectivity, and great versatility. Our work paves the way to realize full co-integration of various functionalized photonic components on single chips
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Photonics and Optoelectronics using 1D and 2D materials
Cambridge International Scholarship (provided by Cambridge Trust
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Functional inks of graphene, metal dichalcogenides and black phosphorus for photonics and (opto) electronics
We discuss the emerging role of solution processing and functional ink formulation in the fabrication of devices
based on two dimensional (2d) materials. By drawing on examples from our research, we show that these inks
allow 2d materials to be exploited in a wide variety of applications, including in photonics and (opto)electronics.
Keywords: Graphene, Transition Metal Dichalcogenides, TMDs, Black Phosphorous, Phosphorene, Functional
Inks, 2d Materials, Inkjet Printing, Ultrafast Lasers, Flexible Electronic