Near-infrared nonreciprocal thermal emitters induced by asymmetric embedded eigenstates

Author(s):  
M.Q. Liu ◽  
C.Y. Zhao
Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2820
Author(s):  
Qi Meng ◽  
Xingqiao Chen ◽  
Wei Xu ◽  
Zhihong Zhu ◽  
Shiqiao Qin ◽  
...  

Graphene absorbers have attracted lots of interest in recent years. They provide huge potential for applications such as photodetectors, modulators, and thermal emitters. In this letter, we design a high-quality (Q) factor resonant graphene absorber based on the phase change material Sb2S3. In the proposed structure, a refractive index grating is formed at the subwavelength scale due to the periodical distributions of amorphous and crystalline states, and the structure is intrinsically flat. The numerical simulation shows that nearly 100% absorption can be achieved at the wavelength of 1550 nm, and the Q factor is more than hundreds due to the loss-less value of Sb2S3 in the near-infrared region. The absorption spectra can be engineered by changing the crystallization fraction of the Sb2S3 as well as by varying the duty cycle of the grating, which can be employed not only to switch the resonant wavelength but also to achieve resonances with higher Q factors. This provides a promising method for realizing integrated graphene optoelectronic devices with the desired functionalities.


2016 ◽  
Vol 2 (12) ◽  
pp. e1600499 ◽  
Author(s):  
Takashi Asano ◽  
Masahiro Suemitsu ◽  
Kohei Hashimoto ◽  
Menaka De Zoysa ◽  
Tatsuya Shibahara ◽  
...  

Control of the thermal emission spectra of emitters will result in improved energy utilization efficiency in a broad range of fields, including lighting, energy harvesting, and sensing. In particular, it is challenging to realize a highly selective thermal emitter in the near-infrared–to–visible range, in which unwanted thermal emission spectral components at longer wavelengths are significantly suppressed, whereas strong emission in the near-infrared–to–visible range is retained. To achieve this, we propose an emitter based on interband transitions in a nanostructured intrinsic semiconductor. The electron thermal fluctuations are first limited to the higher-frequency side of the spectrum, above the semiconductor bandgap, and are then enhanced by the photonic resonance of the structure. Theoretical calculations indicate that optimized intrinsic Si rod-array emitters with a rod radius of 105 nm can convert 59% of the input power into emission of wavelengths shorter than 1100 nm at 1400 K. It is also theoretically indicated that emitters with a rod radius of 190 nm can convert 84% of the input power into emission of <1800-nm wavelength at 1400 K. Experimentally, we fabricated a Si rod-array emitter that exhibited a high peak emissivity of 0.77 at a wavelength of 790 nm and a very low background emissivity of <0.02 to 0.05 at 1100 to 7000 nm, under operation at 1273 K. Use of a nanostructured intrinsic semiconductor that can withstand high temperatures is promising for the development of highly efficient thermal emitters operating in the near-infrared–to–visible range.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tse-An Chen ◽  
Meng-Ju Yub ◽  
Yu-Jung Lu ◽  
Ta-Jen Yen

AbstractPerfect absorbers (PAs) at near infrared allow various applications such as biosensors, nonlinear optics, color filters, thermal emitters and so on. These PAs, enabled by plasmonic resonance, are typically powerful and compact, but confront inherent challenges of narrow bandwidth, polarization dependence, and limited incident angles as well as requires using expensive lithographic process, which limit their practical applications and mass production. In this work, we demonstrate a non-resonant PA that is comprised of six continuous layers of magnesium fluoride (MgF2) and chromium (Cr) in turns. Our device absorbs more than 90% of light in a broad range of 900–1900 nm. In addition, such a planar design is lithography-free, certainly independent with polarization, and presents a further advantage of wide incidence up to 70°. The measured performance of our optimized PA agrees well with analytical calculations of transfer matrix method (TMM) and numerical simulations of finite element method, and can be readily implemented for practical applications.


2020 ◽  
Author(s):  
Tse-An Chen ◽  
Meng-Ju Yub ◽  
Yu-Jung Lu ◽  
Ta-Jen Yen

Abstract Perfect absorbers (PAs) at near infrared allow various applications such as biosensors, nonlinear optics, color filters, thermal emitters and so on. These PAs, enabled by plasmonic resonance, are typically powerful and compact, but confront inherent challenges of narrow bandwidth, polarization dependence, and limited incident angles as well as requires using expensive lithographic process, which limit their practical applications and mass production. In this work, we demonstrate a non-resonant PA that is comprised of six continuous layers of magnesium fluoride (MgF2) and chromium (Cr) in turns. Our device absorbs more than 90% of light in a broad range of 900-1900 nm. In addition, such a planar design is lithography-free, certainly independent with polarization, and presents a further advantage of wide incidence up to 70°. The measured performance of our optimized PA agrees well with analytical calculations of transfer matrix method (TMM) and numerical simulations of finite element method, and can be readily implemented for practical applications.


2013 ◽  
Vol 9 (S296) ◽  
pp. 214-221 ◽  
Author(s):  
Bon-Chul Koo

AbstractSupernova remnants (SNRs) are strong thermal emitters of infrared radiation. The most prominent lines in the near-infrared spectra of SNRs are [Fe II] lines. The [Fe II] lines are from shocked dense atomic gases, so they trace SNRs in dense environments. After briefly reviewing the physics of the [Fe II] emission in SNR shocks, I describe the observational results which show that there are two groups of SNRs bright in [Fe II] emission: middle-aged SNRs interacting with molecular clouds and young core-collapse SNRs in dense circumstellar medium. The SNRs belonging to the former group are also bright in near-infrared H2 emission, indicating that both atomic and molecular shocks are pervasive in these SNRs. The SNRs belonging to the latter group have relatively small radii in general, implying that most of them are likely the remnants of SN IIL/b or SN IIn that had strong mass loss before the explosion. I also comment on the “[Fe II]-H2 reversal” in SNRs and on using the [Fe II]-line luminosity as an indicator of the supernova (SN) rate in galaxies. In the mid- and far-infrared regimes, thermal dust emission is dominant. The dust in SNRs can be heated either by collisions with gas species in a hot plasma or by radiation from a shock front. I discuss the characteristics of the infrared morphology of the SNRs interacting with molecular clouds and their dust heating processes. Finally, I give a brief summary of the detection of SN dust and crystalline silicate dust in SNRs.


Nanoscale ◽  
2020 ◽  
Vol 12 (14) ◽  
pp. 7875-7887 ◽  
Author(s):  
Ying Lan ◽  
Xiaohui Zhu ◽  
Ming Tang ◽  
Yihan Wu ◽  
Jing Zhang ◽  
...  

A near-infrared (NIR) activated theranostic nanoplatform based on upconversion nanoparticles (UCNPs) is developed in order to overcome the hypoxia-associated resistance in photodynamic therapy by photo-release of NO upon NIR illumination.


2020 ◽  
Vol 56 (43) ◽  
pp. 5819-5822
Author(s):  
Jing Zheng ◽  
Yongzhuo Liu ◽  
Fengling Song ◽  
Long Jiao ◽  
Yingnan Wu ◽  
...  

In this study, a near-infrared (NIR) theranostic photosensitizer was developed based on a heptamethine aminocyanine dye with a long-lived triplet state.


2020 ◽  
Vol 48 (6) ◽  
pp. 2657-2667
Author(s):  
Felipe Montecinos-Franjola ◽  
John Y. Lin ◽  
Erik A. Rodriguez

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light &gt;600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.


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