Germanium vertically light-emitting micro-gears generating orbital angular momentum

Al-Attili, Abdelrahman; Burt, Daniel; Zuo, Liang; Higashitarumizu, Naoki; Gardes, Frederic Y.; Oda, Katsuya; Ishikawa, Yasuhiko; Saito, Shinichi

doi:10.1364/oe.26.034675

Cited by 11 publications

(22 citation statements)

References 53 publications

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“…A more efficient way, however, would be realizing a CMOS light source with vertical emission capability. Although VECSEL structures are an option, yet there is a room for novel cavities to compete in terms of fabrication and yield 12 , 13 .…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Vertical emission has been demonstrated from much simpler CMOS-compatible cavities based on germanium (Ge) micro-disks with a grating imposed around the circumference to interact with the confined whispering-gallery modes (WGM) 12 . Such cavities can be micro-disks or rings with a grating etched or deposited on top 13 , a ring with a grating etched on the inner circumference 14 , or a micro-disk with a grating on the outer circumference 12 . The latter form is referred to as a micro-gear cavity 12 , 15 , 16 , having privileges in terms of simpler fabrication as the grating is made from the same disk material, and easier electrical and optical pumping compared to ring cavities.…”

Section: Introductionmentioning

confidence: 99%

“…Such cavities can be micro-disks or rings with a grating etched or deposited on top 13 , a ring with a grating etched on the inner circumference 14 , or a micro-disk with a grating on the outer circumference 12 . The latter form is referred to as a micro-gear cavity 12 , 15 , 16 , having privileges in terms of simpler fabrication as the grating is made from the same disk material, and easier electrical and optical pumping compared to ring cavities. Interestingly, vertically-emitted modes out of micro-gears can have non-zero orbital-angular momentum (OAM) due to the rotating nature of WGMs.…”

Section: Introductionmentioning

confidence: 99%

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Chiral germanium micro-gears for tuning orbital angular momentum

Al-Attili

Burt

Zuo

et al. 2022

Sci Rep

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Group IV light sources with vertical emission and non-zero orbital-angular momentum (OAM) promise to unlock many novel applications. In this report, we demonstrate cylindrically symmetrical germanium micro-gear cavities, fabricated by etching a grating around the circumference of standard micro-disks, with periods ranging from 14 to 22. Photoluminescence (PL) measurements were done to identify the confined whispering-gallery modes (WGM). Finite-difference time-domain (FDTD) simulations were conducted to map the resonant modes to their modal profiles and characteristics. Vertical emission of WGMs with non-zero OAM was demonstrated, with a clear dependence of the OAM order ($$\ell$$ ℓ ) on the WGM azimuthal order and the number of micro-gear grating periods. As the chirality, or the direction of rotation, is not controlled in a symmetrical cavity, we propose introducing staircase or triangular-shaped gear periods resulting in an asymmetry. By choosing the diameter, number of periods, and the asymmetrical direction of the gear-teeth, it is possible to generate OAM signals with certain wavelength, OAM order and chirality.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Chiral germanium micro-gears for tuning orbital angular momentum

Al-Attili

Burt

Zuo

et al. 2022

Sci Rep

Self Cite

View full text Add to dashboard Cite

show abstract

“…The wave-front modulations are mostly based on changing the optical path difference, employing a geometry phase, or controlling diffraction on demand with suitable optical elements, such as spiral phase plates, lens, Pancharatnam-Berry phase elements, and holograph [16][17][18][19][20][21][22][23] and so forth. In addition, the direct generation of OAM light within the laser cavity has been developed, to the great attention of researchers [24][25][26][27][28][29][30][31][32][33][34]. Microring has advantages in realizing compact lasers.…”

Section: Introductionmentioning

confidence: 99%

Vortex Laser Based on a Plasmonic Ring Cavity

Wang

Zhai

2021

Crystals

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The orbital angular momentum (OAM) of the structure light is viewed as a candidate for enhancing the capacity of information processing. Microring has advantages in realizing the compact lasers required for on-chip applications. However, as the clockwise and counterclockwise whispering gallery modes (WGM) appear simultaneously, the emitted light from the normal microring does not possess net OAM. Here, we propose an OAM laser based on the standing-wave WGMs containing clockwise and counterclockwise WGM components. Due to the inhomogeneous intensity distribution of the standing-wave WGM, the single-mode lasing for the OAM light can be realized. Besides, the OAM of the emitted light can be designed on demand. The principle and properties of the proposed laser are demonstrated by numerical simulations. This work paves the way for exploring a single-mode OAM laser based on the plasmonic standing-wave WGMs at the microscale, which can be served as a basic building block for on-chip optical devices.

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