Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Dec 1;8(1):1889.
doi: 10.1038/s41467-017-01662-6.

Unusual Scaling Laws for Plasmonic Nanolasers Beyond the Diffraction Limit

Affiliations
Free PMC article

Unusual Scaling Laws for Plasmonic Nanolasers Beyond the Diffraction Limit

Suo Wang et al. Nat Commun. .
Free PMC article

Abstract

Plasmonic nanolasers are a new class of amplifiers that generate coherent light well below the diffraction barrier bringing fundamentally new capabilities to biochemical sensing, super-resolution imaging, and on-chip optical communication. However, a debate about whether metals can enhance the performance of lasers has persisted due to the unavoidable fact that metallic absorption intrinsically scales with field confinement. Here, we report plasmonic nanolasers with extremely low thresholds on the order of 10 kW cm-2 at room temperature, which are comparable to those found in modern laser diodes. More importantly, we find unusual scaling laws allowing plasmonic lasers to be more compact and faster with lower threshold and power consumption than photonic lasers when the cavity size approaches or surpasses the diffraction limit. This clarifies the long-standing debate over the viability of metal confinement and feedback strategies in laser technology and identifies situations where plasmonic lasers can have clear practical advantage.

Conflict of interest statement

The authors declare no competing financial interests.

Figures

Fig. 1
Fig. 1
Schematic of plasmonic and photonic lasers and their cavity modes. a Top: schematic of the plasmonic nanolaser devices consisting of a nanosquare gain material on top of metal separated by a few nanometers of dielectric. Bottom: top and side views of electric field (|E|) profiles of a cavity mode in a 700 × 700 × 100 nm plasmonic cavity. b Top: schematic of the photonic nanolaser devices consisting of a nanosquare gain material on top of dielectric. Bottom: top and side views of electric field (|E|) profiles of a cavity mode in a 700 × 700 × 100 nm photonic cavity. In both panels, L and T are the length and thickness of the nanosquare, respectively, and TIR represents total internal reflection
Fig. 2
Fig. 2
Room temperature ultralow threshold plasmonic nanolaser. a Laser spectrum of a plasmonic nanolaser with a threshold of ~32 kW cm−2. Inset: atomic force microscope image of the device. b Spectra normalized to peak value vs. pump power highlighting the emergence of a dominant laser mode with reduced linewidth over the spontaneous emission. c Light–light curve of the plasmonic nanolaser (dots show data values). The spontaneous emission coupling (β) factor of the nanolaser is about 0.09 (red line). Black, pink, and blue lines are reference light–light curves corresponding to β = 1, β = 0.5, β = 0.05
Fig. 3
Fig. 3
Scaling laws of physical volume vs. thickness. a The relationship between T and V for only the lasing plasmonic and photonic cavities, where T and V are the thickness and volume of cadmium selenide nanosquares, respectively. The relationship between T and V for the plasmonic nanolasers (black dots) follows the natural scaling law of TV13 determined by the material growth process (black line). However, for photonic devices, the scaling of T shifts significantly away from the natural material scaling law when T approaches the diffraction limit (red dots). The red line is a guide to the eye. Error bar shows the thickness range for a certain number of measured devices with the same volume. b The relationship between cadmium selenide area A and V for only the lasing plasmonic (black dots) and photonic cavities (red dots), where A is the area of cadmium selenide nanosquares. Black line: guide to the eye of AV23. Red line: guide to the eye of AV. Error bar shows the area range for a certain number of measured devices with the same volume. c Cadmium selenide thickness distribution histogram for plasmonic (black columns) and photonic (red columns) lasers. Lines: Gaussian distribution fittings. d Cadmium selenide physical volume distribution histogram for plasmonic (black columns) and photonic (red columns) lasers. Lines: Gaussian distribution fittings. In all the panels, λ refers to 700 nm
Fig. 4
Fig. 4
Scaling laws of threshold and power consumption vs. device sizes. a, b Laser threshold scaling as a function of device volume for plasmonic (black dots) and photonic (red dots) nanolasers with thicknesses in the range of 100 nm < T < 150 nm (a), and 250 nm < T < 350 nm (b). Inset of a: Laser threshold scaling as a function of device volume for plasmonic nanolasers with thicknesses in the range of T < 100 nm. c, d Power consumption scaling as a function of device volume for plasmonic nanolasers with thicknesses in the ranges of 100 nm < T < 150 nm (black dots) and T < 100 nm (olive dots) (c), and 250 nm < T < 350 nm (black dots) (d), and for photonic nanolasers with thicknesses in the ranges of 100 nm < T < 150 nm (red dots) (c), and 250 nm < T < 350 nm (red dots) (d). Lines in ad show exponential fittings to data. e, f Quantitative analysis of power consumption scaling of plasmonic and photonic nanolasers. For each range of device thickness, a phenomenological scaling law is expressed as PthpowerVα, where Pthpower is the power consumption at threshold and α is an exponent. e shows α vs. T, highlighting the distinct scaling of power consumption of photonic (red dots) and plasmonic lasers (black dots) near the diffraction limit. f shows the power consumption of plasmonic and photonic nanolasers at a volume of 0.5λ 3 (black dots for plasmonic nanolasers, red dots for photonic nanolasers) and 2λ 3 (dark cyan circles for plasmonic nanolasers, orange circles for photonic nanolasers) for varied thickness, where lines are guides to the eye. In all the panels, λ refers to 700 nm
Fig. 5
Fig. 5
Scaling laws of emission lifetime vs. physical volume and laser threshold. a Scaling laws of lifetime as a function of device volume for plasmonic (black dots) and photonic (red dots) nanolasers. Error bar shows the lifetime range for a certain number of measured devices with the same volume. Lines are guides to the eye showing simulated relationship between lifetime (τ) and physical volume (V), where black line refers to τV0.53, red line refers to τV0.60, and magenta line refers to τV0.22. λ refers to 700 nm. bd Scaling laws of emission lifetime vs. threshold of plasmonic (black dots) and photonic (red dots) nanolasers in the thicknesses ranges of 100 nm < T < 150 nm (b), 150 nm < T < 250 nm (c), and 250 nm < T < 350 nm (d). Lines show exponential fittings to data by τPthα1, where α 1 is an exponent and P th is the threshold. For plasmonic lasers, the exponents are −0.77, −0.67, and −0.65 in b, c and d, respectively. For photonic lasers, the exponents are −0.49, −0.70, and −0.84 in b, c and d, respectively

Similar articles

See all similar articles

Cited by 2 articles

  • Electron beam-based metrology after CMOS.
    Liddle JA, Hoskins BD, Vladár AE, Villarrubia JS. Liddle JA, et al. APL Mater. 2018;6:10.1063/1.5038249. doi: 10.1063/1.5038249. APL Mater. 2018. PMID: 30984475 Free PMC article.
  • Miniature lasers: Is metal a friend or foe?
    Noginov MA, Khurgin JB. Noginov MA, et al. Nat Mater. 2018 Feb;17(2):116-117. doi: 10.1038/nmat5065. Epub 2018 Jan 1. Nat Mater. 2018. PMID: 29300053 Review. No abstract available.

References

    1. Noda S. Seeking the ultimate nanolaser. Science. 2006;314:260–261. doi: 10.1126/science.1131322. - DOI - PubMed
    1. Hill MT, Gather MC. Advances in small lasers. Nat. Photonics. 2014;8:908–918. doi: 10.1038/nphoton.2014.239. - DOI
    1. Stockman MI. On the fast track. Nat. Phys. 2014;10:799–800. doi: 10.1038/nphys3127. - DOI
    1. Eaton SW, Fu A, Wong AB, Ning CZ, Yang PD. Semiconductor nanowire lasers. Nat. Rev. Mater. 2016;1:16028. doi: 10.1038/natrevmats.2016.28. - DOI
    1. Bergman DJ, Stockman MI. Surface plasmon amplification by stimulated emission of radiation: quantum generation of coherent surface plasmons in nanosystems. Phys. Rev. Lett. 2003;90:027402. doi: 10.1103/PhysRevLett.90.027402. - DOI - PubMed

Publication types

Feedback