東華大學圖書館 |

On-Chip UV/VIS Optical Spectrometer.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	On-Chip UV/VIS Optical Spectrometer./
作者:	Sarwar, Tuba.
面頁冊數:	1 online resource (167 pages)
附註:	Source: Dissertations Abstracts International, Volume: 84-12, Section: B.
Contained By:	Dissertations Abstracts International84-12B.
標題:	Engineering. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30548559click for full text (PQDT)
ISBN:	9798379566708

On-Chip UV/VIS Optical Spectrometer.
Sarwar, Tuba.

On-Chip UV/VIS Optical Spectrometer. - 1 online resource (167 pages)

Source: Dissertations Abstracts International, Volume: 84-12, Section: B.

Thesis (Ph.D.)--University of Michigan, 2023.

Includes bibliographical references

Optical spectroscopy is one of the most widely used analytical techniques in science and engineering. Miniaturizing an optical spectrometer can allow for a portable and handheld system and lead to new opportunities for the Internet of Things (IoT) and lab-on-a-chip applications. Visible-light spectrometers have broad applications in UV-VIS, fluorescence, and chemi-/electro-luminescence spectroscopy. A spectrometer is a highly complex system consisting of optical, mechanical, and image processing units. Miniaturizing such a system is a nontrivial task involving the ability to integrate multiple material platforms and careful planning of performance tradeoffs, such as spectral resolution, sensitivity, system size, and cost. Among various approaches, spectrometers based on reconstructive algorithms shift the complexity of processing spectral information from physical components to software computations. With the steady growth of computational power per watt-dollar, this approach has become increasingly promising in constructing an extremely compact spectroscopic system.In this work, a low-profile reconstructive spectrometer with only the thickness of the semiconductors and an operating range spanning the visible wavelength spectrum is reported. This spectrometer concept is based on wavelength-selective semiconductor photodiodes monolithically integrated on a chip area of 0.16 mm2. The absorption properties of individual photodiodes were tuned via local strain engineering in compressively strained Indium Gallium Nitride/Gallium Nitride (InGaN/GaN) multiple quantum well heterostructures. By varying the diameters of individual nanopillars, the cutoff wavelengths of absorption were varied across the chip. The intrinsic wavelength selectivity is insensitive to the incident angle of light. The built-in GaN pn junction enabled a direct photocurrent measurement.In this dissertation, we first proposed and demonstrated a proof-of-concept spectrometer based on 14 photodiodes, without any external optics or spectral filtering components, in the wavelength range of 450 - 590 nm. Using a non-negative least square (NNLS) algorithm enhanced by orthogonal matching pursuit (OMP), the spectrum of a test light source was reconstructed.Secondly, we monolithically integrated a GaN-based LED with the spectroscopic chip. An optical blocking structure was used to suppress the LED-photodetector interference and was shown to be essential for spectroscopic functionality. A proof of concept using a reflection spectroscopy configuration was experimentally conducted to validate the feasibility of simultaneously operating the LED excitation light source and the photodiodes. Spectral reconstruction using an NNLS algorithm enhanced with OMP was shown to reconstruct the signal from the reflection spectroscopy. No external optics, such as collimation optics and apertures were used.Thirdly, we discussed the spectrometer design conditions enabling an ultrathin form factor to increase the light-harvesting efficiency. We proposed and demonstrated a simple strategy, utilizing the well-established sapphire substrate patterning process to greatly enhance the absorption efficiency while maintaining a large acceptance angle for the incident light. We also demonstrate that spectroscopic performance can be significantly enhanced with this strategy.Finally, we demonstrated a reconstructive spectrometer consisting of 16 spectral encoders to deliver a decent spectral reconstruction performance in the wavelength range of 400 - 650 nm. The accuracies of spectral peak positions and intensity ratios between peaks were found to be 0.97% and 10.4%, respectively. No external optics such as collimation optics and apertures were used, enabled by angle-insensitive light-harvesting structures, including an array of cone-shaped back-reflector fabricated on the underside of the sapphire substrate. The small chip area and a computationally efficient spectral reconstruction algorithm make the proposed spectrometer especially suitable for wearable applications.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798379566708Subjects--Topical Terms:

586835
Engineering.
Subjects--Index Terms:

Gallium nitride semiconductorsIndex Terms--Genre/Form:

542853
Electronic books.

On-Chip UV/VIS Optical Spectrometer.
LDR:05488nmm a2200421K 4500 001 2362777
005 20231102122823.5
006 m o d
007 cr mn ---uuuuu
008 241011s2023 xx obm 000 0 eng d
020 $a 9798379566708
035 $a (MiAaPQ)AAI30548559
035 $a (MiAaPQ)umichrackham004913
035 $a AAI30548559
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Sarwar, Tuba. $3 3703517
245 1 0 $a On-Chip UV/VIS Optical Spectrometer.
264 0 $c 2023
300 $a 1 online resource (167 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 84-12, Section: B.
500 $a Advisor: Ku, Pei-Cheng.
502 $a Thesis (Ph.D.)--University of Michigan, 2023.
504 $a Includes bibliographical references
520 $a Optical spectroscopy is one of the most widely used analytical techniques in science and engineering. Miniaturizing an optical spectrometer can allow for a portable and handheld system and lead to new opportunities for the Internet of Things (IoT) and lab-on-a-chip applications. Visible-light spectrometers have broad applications in UV-VIS, fluorescence, and chemi-/electro-luminescence spectroscopy. A spectrometer is a highly complex system consisting of optical, mechanical, and image processing units. Miniaturizing such a system is a nontrivial task involving the ability to integrate multiple material platforms and careful planning of performance tradeoffs, such as spectral resolution, sensitivity, system size, and cost. Among various approaches, spectrometers based on reconstructive algorithms shift the complexity of processing spectral information from physical components to software computations. With the steady growth of computational power per watt-dollar, this approach has become increasingly promising in constructing an extremely compact spectroscopic system.In this work, a low-profile reconstructive spectrometer with only the thickness of the semiconductors and an operating range spanning the visible wavelength spectrum is reported. This spectrometer concept is based on wavelength-selective semiconductor photodiodes monolithically integrated on a chip area of 0.16 mm2. The absorption properties of individual photodiodes were tuned via local strain engineering in compressively strained Indium Gallium Nitride/Gallium Nitride (InGaN/GaN) multiple quantum well heterostructures. By varying the diameters of individual nanopillars, the cutoff wavelengths of absorption were varied across the chip. The intrinsic wavelength selectivity is insensitive to the incident angle of light. The built-in GaN pn junction enabled a direct photocurrent measurement.In this dissertation, we first proposed and demonstrated a proof-of-concept spectrometer based on 14 photodiodes, without any external optics or spectral filtering components, in the wavelength range of 450 - 590 nm. Using a non-negative least square (NNLS) algorithm enhanced by orthogonal matching pursuit (OMP), the spectrum of a test light source was reconstructed.Secondly, we monolithically integrated a GaN-based LED with the spectroscopic chip. An optical blocking structure was used to suppress the LED-photodetector interference and was shown to be essential for spectroscopic functionality. A proof of concept using a reflection spectroscopy configuration was experimentally conducted to validate the feasibility of simultaneously operating the LED excitation light source and the photodiodes. Spectral reconstruction using an NNLS algorithm enhanced with OMP was shown to reconstruct the signal from the reflection spectroscopy. No external optics, such as collimation optics and apertures were used.Thirdly, we discussed the spectrometer design conditions enabling an ultrathin form factor to increase the light-harvesting efficiency. We proposed and demonstrated a simple strategy, utilizing the well-established sapphire substrate patterning process to greatly enhance the absorption efficiency while maintaining a large acceptance angle for the incident light. We also demonstrate that spectroscopic performance can be significantly enhanced with this strategy.Finally, we demonstrated a reconstructive spectrometer consisting of 16 spectral encoders to deliver a decent spectral reconstruction performance in the wavelength range of 400 - 650 nm. The accuracies of spectral peak positions and intensity ratios between peaks were found to be 0.97% and 10.4%, respectively. No external optics such as collimation optics and apertures were used, enabled by angle-insensitive light-harvesting structures, including an array of cone-shaped back-reflector fabricated on the underside of the sapphire substrate. The small chip area and a computationally efficient spectral reconstruction algorithm make the proposed spectrometer especially suitable for wearable applications.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Engineering. $3 586835
650 4 $a Computer engineering. $3 621879
650 4 $a Optics. $3 517925
650 4 $a Electrical engineering. $3 649834
653 $a Gallium nitride semiconductors
653 $a Reflection spectroscopy
653 $a Reconstructive spectrometers
653 $a Photodetection
653 $a Sapphire
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0537
690 $a 0752
690 $a 0544
690 $a 0464
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a University of Michigan. $b Electrical and Computer Engineering. $3 3284714
773 0 $t Dissertations Abstracts International $g 84-12B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30548559 $z click for full text (PQDT)