Lasers producing tailored beams

Miyai, Eiji; Sakai, Kyosuke; Okano, Takayuki; Kunishi, Wataru; Ohnishi, Dai; Noda, Susumu

doi:10.1038/441946a

Cited by 263 publications

(140 citation statements)

References 10 publications

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“…support to the premise that the GPH devices are operating on radiative modes, where the emission is naturally single lobed without any π-phase shift in the photonic lattice [31][32][33] .…”

Section: ) H(r)mentioning

confidence: 83%

Efficient power extraction in surface-emitting semiconductor lasers using graded photonic heterostructures

et al. 2012

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symmetric and antisymmetric band-edge modes exist in distributed feedback surface-emitting semiconductor lasers, with the dominant difference being the radiation loss. Devices generally operate on the low-loss antisymmetric modes, although the power extraction efficiency is low. Here we develop graded photonic heterostructures, which localize the symmetric mode in the device centre and confine the antisymmetric modes close to the laser facet. This modal spatial separation is combined with absorbing boundaries to increase the antisymmetric mode loss, and force device operation on the symmetric mode, with elevated radiation efficiency. Application of this concept to terahertz quantum cascade lasers leads to record-high peakpower surface emission ( > 100 mW) and differential efficiencies (230 mW A − 1 ), together with low-divergence, single-lobed emission patterns, and is also applicable to continuous-wave operation. such flexible tuning of the radiation loss using graded photonic heterostructures, with only a minimal influence on threshold current, is highly desirable for optimizing secondorder distributed feedback lasers.

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Section: ) H(r)mentioning

confidence: 83%

Efficient power extraction in surface-emitting semiconductor lasers using graded photonic heterostructures

et al. 2012

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“…Researchers first observed this effect via a suppression of radiation into the normal direction in a surface-emitting distributed feedback laser with onedimensional periodicity 58,59 . This led to PhC surface emitting lasers (PCSELs) that lase through BICs with two-dimensional periodicity 214,215 , followed by the realizations of various lasing patterns 216,217 , lasing at the blue-violet wavelengths 218 , and lasing with organic molecules 221 . The suppressed radiation at the normal direction means that a PCSEL can have a low lasing threshold but also with a limited output power.…”

Section: Applications Of Bics and Quasi-bicsmentioning

confidence: 99%

“…This makes them useful for many optical and photonic applications. In particular, the macroscopic size (on the centimeter scale or larger) and ease of fabrication make BICs in PhC slabs unique for large-area high-power applications such as lasers [214][215][216][217][218][219] , sensors 220,221 , and filters 222 .…”

Section: Applications Of Bics and Quasi-bicsmentioning

confidence: 99%

Bound states in the continuum

et al. 2016

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Bound states in the continuum are waves that, defying conventional wisdom, remain localized even though they coexist with a continuous spectrum of radiating waves that can carry energy away. Their existence was first proposed in quantum mechanics and, being a general wave phenomenon, later identified in electromagnetic, acoustic, and water waves. They have been studied in a wide variety of material systems such as photonic crystals, optical waveguides and fibers, piezoelectric materials, quantum dots, graphene, and topological insulators. This Review describes recent developments in this field with an emphasis on the physical mechanisms that lead to these unusual states across the seemingly very different platforms. We discuss recent experimental realizations, existing applications, and directions for future work.

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“…Two-dimensional surface-emitting photonic-crystal lasers often emit donut beams with azimuthal polarization, 4 while surface plasmon lasers create radially polarized vector-vortex beams. 5 Devices can be tailored to emit other beam shapes, 6 but information about the phase and amplitude profile is scarce and either has low resolution 7 or an electrical contact blocks the view. 8 A better understanding of gain and feedback in plasmonic systems is important for improving photonics applications that use the strong confinement and light−matter interaction provided by plasmons.…”

mentioning

confidence: 99%

Measurement of the Phase and Intensity Profile of Surface Plasmon Laser Emission

2016

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ABSTRACT:We study the near-and far-field radiation patterns of surface plasmon (SP) lasers in metal hole arrays and observe radially polarized vortex-vector laser beams in both near and far field. Besides the intensity profile, also the complementary phase profile is obtained with a beam block experiment, where we block part of the beam in the near field, measure the resulting changes in the far field, and retrieve the phase using an iterative algorithm. This phase profile provides valuable information on the feedback mechanisms and coherence of the laser and shows that our SP laser operates in a phaseslip mode instead of a pure dark mode. To explain our observations, we extend the standard model for distributed feedback lasers by introducing a position dependence in the optical gain and refractive index. KEYWORDS: surface plasmon laser, distributed feedback, phase retrieval, metal hole array, plasmonic crystal laser, active mirror O ptically coherent laser radiation can be generated if both gain and optical feedback are present in a medium. Our physical understanding of these phenomena originates from comparisons between measured intensity distributions and models of both the amplitude and the phase of the radiation. The optical phase is typically discarded because it evolves too fast to resolve directly with an optical detector or a camera. The inability to measure both amplitude and phase of the emitted laser radiation presents a recurring challenge in optics and limits progress in the field.More ingenious schemes are needed to observe the phase using slow detectors. One of the simplest schemes uses the mixing of the amplitude and phase information on the light field upon propagation. At the laser exit the amplitude contains information where the light is emitted, while the phase profile contains information about the propagation direction. Recording the intensity distribution on different positions allows retrieval of the phase information by an iterative algorithm. 1−3The ability to resolve both amplitude and phase is particularly relevant for lasers that emit nonstandard beam profiles that are not yet fully understood. Examples of such lasers are surface-emitting distributed feedback lasers, such as photonic and plasmonic crystal lasers. Two-dimensional surface-emitting photonic-crystal lasers often emit donut beams with azimuthal polarization, 4 while surface plasmon lasers create radially polarized vector-vortex beams. 5 Devices can be tailored to emit other beam shapes, 6 but information about the phase and amplitude profile is scarce and either has low resolution 7 or an electrical contact blocks the view. 8 A better understanding of gain and feedback in plasmonic systems is important for improving photonics applications that use the strong confinement and light−matter interaction provided by plasmons. These applications include ultrasensitive molecule sensors (SERS), 9 anticounterfeiting measures, 10 perfect absorbers, 11 ultrafast optical modulators, 12 and future metal−dielectric metamaterials consi...

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Lasers producing tailored beams

Cited by 263 publications

References 10 publications

Efficient power extraction in surface-emitting semiconductor lasers using graded photonic heterostructures

Efficient power extraction in surface-emitting semiconductor lasers using graded photonic heterostructures

Bound states in the continuum

Measurement of the Phase and Intensity Profile of Surface Plasmon Laser Emission

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