Abstract:We present single-mode nanowire (NW) lasers with ultralow threshold in the near-infrared spectral range. To ensure the single-mode operation, the NW diameter and length are reduced specifically to minimize the longitudinal and transverse modes of the NW cavity. Increased optical losses and reduced gain volume by the dimension reduction are compensated by excellent NW morphology and InGaAs/GaAs multi-quantum disks. At 5 K, a threshold low as 1.6 μJ/cm 2 per pulse is achieved with a resulting quality factor exce… Show more
“…1g , where the insets display the end facets. The flat end facets of the NW are perpendicular to the longitudinal direction, which enables high reflectance for the guided mode in the NW as well as resonance modes of the optical cavity with high-quality factors 19 . Fig.…”
Section: Resultsmentioning
confidence: 99%
“…NW lasers have been demonstrated in a variety of materials, such as III–V and II–VI compound semiconductors, and perovskites 3 , 8 – 16 . With the successful introduction of quantum confined structures such as quantum dots and quantum wells into NWs, the gain characteristics could be flexibly tuned and NW lasers exhibit superior device performance, like low threshold and high-temperature stability 10 , 11 , 17 – 19 . In recent years, the development of selective area epitaxy enables the demonstration of NW-array-based lasers with other photonic modes 6 , 20 , 21 .…”
Semiconductor nanowires (NWs) could simultaneously provide gain medium and optical cavity for performing nanoscale lasers with easy integration, ultracompact footprint, and low energy consumption. Here, we report III–V semiconductor NW lasers can also be used for self-frequency conversion to extend their output wavelengths, as a result of their non-centrosymmetric crystal structure and strongly localized optical field in the NWs. From a GaAs/In0.16Ga0.84As core/shell NW lasing at 1016 nm, an extra visible laser output at 508 nm is obtained via the process of second-harmonic generation, as confirmed by the far-field polarization dependence measurements and numerical modeling. From another NW laser with a larger diameter which supports multiple fundamental lasing wavelengths, multiple self-frequency-conversion lasing modes are observed due to second-harmonic generation and sum-frequency generation. The demonstrated self-frequency conversion of NW lasers opens an avenue for extending the working wavelengths of nanoscale lasers, even to the deep ultraviolet and THz range.
“…1g , where the insets display the end facets. The flat end facets of the NW are perpendicular to the longitudinal direction, which enables high reflectance for the guided mode in the NW as well as resonance modes of the optical cavity with high-quality factors 19 . Fig.…”
Section: Resultsmentioning
confidence: 99%
“…NW lasers have been demonstrated in a variety of materials, such as III–V and II–VI compound semiconductors, and perovskites 3 , 8 – 16 . With the successful introduction of quantum confined structures such as quantum dots and quantum wells into NWs, the gain characteristics could be flexibly tuned and NW lasers exhibit superior device performance, like low threshold and high-temperature stability 10 , 11 , 17 – 19 . In recent years, the development of selective area epitaxy enables the demonstration of NW-array-based lasers with other photonic modes 6 , 20 , 21 .…”
Semiconductor nanowires (NWs) could simultaneously provide gain medium and optical cavity for performing nanoscale lasers with easy integration, ultracompact footprint, and low energy consumption. Here, we report III–V semiconductor NW lasers can also be used for self-frequency conversion to extend their output wavelengths, as a result of their non-centrosymmetric crystal structure and strongly localized optical field in the NWs. From a GaAs/In0.16Ga0.84As core/shell NW lasing at 1016 nm, an extra visible laser output at 508 nm is obtained via the process of second-harmonic generation, as confirmed by the far-field polarization dependence measurements and numerical modeling. From another NW laser with a larger diameter which supports multiple fundamental lasing wavelengths, multiple self-frequency-conversion lasing modes are observed due to second-harmonic generation and sum-frequency generation. The demonstrated self-frequency conversion of NW lasers opens an avenue for extending the working wavelengths of nanoscale lasers, even to the deep ultraviolet and THz range.
“…Through strong light confinement for obtaining sufficient gain, ZnO NWs lasers could be well optimized to realize lasing emissions with a low light loss. [49,50]…”
Section: Lasing Analysis Of Zno Nws Without and With Pt Metalmentioning
Among the most studied nanomaterials, 1D nanowires (NWs) with ultra-high intrinsic photoelectric gain, multiple array light confinement, and subwavelength size effects could be suitable for designing structures with advanced performance, which fully satisfy the practical needs. [9][10][11][12] Due to the small size and self-formed cavity, semiconductor NWs have attracted more and more attention to fabricating nanostructured lasers, [13] which could provide natural cavities for low size lasers. [15][16][17][18] Among all the low dimensional materials, ZnO is considered to be a promising candidate as a UV media considering its wide bandgap (3.37 eV) and large exciton binding energy of 60 meV, which is suitable for fabricating room temperature optoelectronic devices. [19][20][21] Compared with GaN (25 meV), the large exciton binding energy of ZnO material enables to achieve room temperature optoelectronic devices with high stability. At present, optically pumped UV lasing action in ZnO was realized as the gain medium with single forms such as microwires, microspheres, nanoribbons, nanowires, etc. [22][23][24][25] and the preparation methods could be thermal oxidation, chemical vapor deposition (CVD), hydrothermal reaction, magnetron sputtering, atomic layer deposition (ALD), pulsed laser Due to optical radiation losses, a high pumping threshold or low temperature is necessary for driving ultraviolet (UV) light emission devices, and surface/interface engineering method is one of the alternatives for tailoring photon behavior. Here, a fully integrated nanowire (NW) laser device is thus constructed, resulting in suppressed interface light loss. Enhanced UV spontaneous and lasing emission is observed due to adequate gain to compensate for the optical loss. Applying well-aligned ZnO NW cavities, optimized UV spontaneous and lasing emission is realized, supporting an effective optical path through interface engineering for photon extraction. As proven by experimental results, through interface integration with Pt metal for ZnO NWs, 170% photoluminescence (PL) emission enhancement accompanied by 145% broaden emission spectra width in the UV region is obtained. It is also observed that more lasing modes appeare when excitation density is high enough, lasing modes interspacing of around 3 nm, and full width at half maximum of the modes <0.003 eV for the lasing device could be observed. The detailed optical simulation is proposed to understand the physical origin of internal mechanisms contributing to the optimized spontaneous and stimulated lasing emission behaviors.
“…Increasing the In composition of the ternary alloy provides tunability across the near-infrared (NIR) region of the electromagnetic spectrum to a minimum value of 0.354 eV at 300 K . This optical tunability allows extended applications related to infrared optics and laser materials. − However, methods of achieving the growth of high-quality crystalline GaAs are currently not cost-competitive due to their higher production costs and lower throughput relative to Si growth methods. Thus, the development of alternative low-cost routes to GaAs growth is required to meet the growing needs of the optoelectronics industry …”
Compared to Si, GaAs
offers unique material advantages such as
high carrier mobility and energy conversion efficiency, making GaAs
a leading competitor to replace Si on several technological fronts
related to optoelectronics and solar energy conversion. Alloying the
GaAs lattice with elemental In allows the direct bandgap of the resulting
ternary alloy to be tuned across the near-infrared (NIR) region of
the electromagnetic spectrum from ∼0.9 to 3.5 μm. However,
methods of fabricating high-quality crystalline GaAs are currently
limited by their high cost and low throughput relative to Si growth
methods, suggesting the need for alternative low-cost routes to GaAs
growth and alloying. This research documents the first instance in
the literature of the electrodeposition and controlled alloying of
polycrystalline In
x
Ga1–x
As films at ambient pressure and near-room temperature
using the electrochemical liquid–liquid–solid (ec-LLS)
process. X-ray diffraction and Raman spectroscopy support the polycrystalline
growth of (111)-oriented In
x
Ga1–x
As films. Consistent redshifts of the GaAs-like TO
peaks were observed in the Raman data as the In composition of the
liquid metal electrode was increased. Optical bandgaps, determined
via diffuse reflectance measurements, displayed a consistent decrease
with the increase in the In composition of In
x
Ga1–x
As films. While Raman,
diffuse reflectance, and energy-dispersive X-ray spectroscopy data
support controlled alloying efforts, all techniques suggest an overall
decrease of the In/Ga ratios present in deposited films relative to
those of the liquid metal electrodes. These results lend support for
the continued development of ec-LLS as a viable method of achieving
crystalline growth and alloying of binary and ternary semiconductor
material systems using a benchtop setup under ambient pressure and
near-room temperature.
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