Concentric circular focusing reflector realized using high index contrast gratings

Fang, Wenjing; Huang, Yongqing; Fei, Jiarui; Duan, Xiaofeng; Li, Kai; Ren, Xiaomin

doi:10.1016/j.optcom.2017.06.096

Cited by 6 publications

(8 citation statements)

References 30 publications

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“…However, it is still 23 times larger than the intensity of the incident light, which to the best of our knowledge gives our design the highest light intensity at the focal point that has been reported so far among subwavelength grating mirrors. 15 , 16 …”

Section: Results and Discussionmentioning

confidence: 99%

“…This is about 29% of the simulated value and, to the best of our knowledge, by far the highest value reported so far in the literature for any subwavelength grating-based mirror or lens. 15 , 16 …”

Section: Discussionmentioning

confidence: 99%

“…Nonetheless, the light intensity at the focal point shown in this article is over an order of magnitude higher than any reported for a focusing mirror previously in the literature. 15 , 16 Out of five reports on focusing grating mirrors, 13 − 17 only two 15 , 16 provide information on the light intensity relative to the incident light intensity at the focal point, which is 1.2 at best.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Demonstration of Light Focusing Enabled by Monolithic High-Contrast Grating Mirrors

Komar

Gębski

Lott

et al. 2021

ACS Appl. Mater. Interfaces

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We present the first experimental demonstration of a planar focusing monolithic subwavelength grating mirror. The grating is formed on the surface of GaAs and focuses 980 nm light in one dimension on the high-refractive-index side of the mirror. According to our measurements, the focal length is 475 μm (300 μm of which is GaAs) and the numerical aperture is 0.52. The intensity of the light at the focal point is 23 times larger than that of the incident light. To the best of our knowledge, this is the highest value reported for a grating mirror. Moreover, the full width at half-maximum (FWHM) at the focal point is only 3.9 μm, which is the smallest reported value for a grating mirror. All of the measured parameters are close to or very close to the theoretically predicted values. Our realization of a sophisticated design of a focusing monolithic subwavelength grating opens a new avenue to technologically simple fabrication of the gratings for use in diverse optoelectronic materials and applications.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Demonstration of Light Focusing Enabled by Monolithic High-Contrast Grating Mirrors

Komar

Gębski

Lott

et al. 2021

ACS Appl. Mater. Interfaces

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show abstract

“…[31][32][33] In addition, another type of periodic or non-periodic concentric-circular HCGs not only provide high reflectivity, but also achieve distinct point focusing ability, while readily realizing wafer-scale integration of Si-based optoelectronic devices. [34][35][36] In this letter, a high focusing-reflection (FR) uni-traveling-carrier photodetector (FR-UTC-PD) structure is proposed by using wafer-bonding technology to improve the responsivity of UTC-PDs without sacrificing the bandwidth performance. The schematic diagram of the FR-UTC-PD is shown in Fig.…”

mentioning

confidence: 99%

“…Obviously, the discrete grating bars along the 𝑥 direction coincides exactly with the theoretical calculation results. Furthermore, the FR characteristics of the NP-CC-HCG mirror are modeled and simulated using COMSOL that is based on the finite element method (FEM) 37) with a preset focal length of 12 μm 34) to avoid the duplicate calculation of the mass data, and the relevant result is shown in Fig. 3 (b).…”

mentioning

confidence: 99%

Uni-traveling-carrier photodetector with high-contrast grating focusing-reflection mirrors

Chen

Fang

Huang

et al. 2019

Appl. Phys. Express

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A novel uni-traveling-carrier photodetector (UTC-PD) structure with an integrated focusingreflection (FR) mirror realized by a non-periodic concentric circular high-contrast grating (NP-CC-HCG), referred to as FR-UTC-PD, is proposed to enhance responsivity in conventional UTC-PDs. The FR-UTC-PD allows improving the responsivity by 36.5% at a 1.55-μm wavelength as compared to a UTC-PD without integrated an FR mirror with 84.59% reflectivity. For 40-μm-diameter PDs, the obtained 3-dB bandwidths are unaltered with values of 18 GHz at -3.0 V bias voltage. The radio-frequency (RF) output power and photocurrent are -1.77 dBm and 17.56 mA, respectively, at 10 GHz and the -6.0 V bias voltage. Submitted To APEX 2The high-speed and high-responsivity photodetectors operating at long wavelength regimes have been widely used in wireless communication system, broadband optical communication system, and high-frequency measurement systems. 1-2) The uni-travelingcarrier photodetector (UTC-PD) [3][4] only utilizes electrons as active carriers and thus easily exhibits high-speed and high-output characteristics simultaneously, which has been of great interest both for research [5][6][7][8] and broad ranges of applications. 9-14) Moreover, high-speed UTC-PDs also need high-responsivity to prevent the waveform distortion of the high-speed signals and thus degrade the total power consumption of the system. Therefore, it is very important to adopt methods to further improve the bandwidth and responsivity performance for UTC-PDs. For instance, a UTC-PD with the downscaling absorber thickness and absorption area starting with 86 nm, 13μm 2 scaled down to 30 nm, 5 μm 2 , achieves 3-dB bandwidths from 235 GHz to 310 GHz while having the responsivities from 0.126 A/W to 0.07 A/W, respectively, at a 1.55-μm wavelength. [5][6] In order to achieve higher responsivity, a UTC-PD with a 1.2-μm-thick InGaAs absorber exhibits the responsivity up to 1.0 A/W, with a 3-dB bandwidth of only 9 GHz under low photocurrent. 15) Hence, balancing the tradeoff between the bandwidth and responsivity in UTC-PDs has become an active research area.Recently, various structures have been explored to address the bandwidth-responsivity

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Design of grating based narrow band reflector on SOI waveguide

Sharma

Rana

Wang

et al. 2021

Optik

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Concentric circular focusing reflector realized using high index contrast gratings

Cited by 6 publications

References 30 publications

Experimental Demonstration of Light Focusing Enabled by Monolithic High-Contrast Grating Mirrors

Experimental Demonstration of Light Focusing Enabled by Monolithic High-Contrast Grating Mirrors

Uni-traveling-carrier photodetector with high-contrast grating focusing-reflection mirrors

Design of grating based narrow band reflector on SOI waveguide

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