BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4//
BEGIN:VEVENT
UID:20260728T154738EDT-5903NF7EIi@132.216.98.100
DTSTAMP:20260728T194738Z
DESCRIPTION:Abstract\n\nAn hour of sunlight can satisfy global power consum
 ption for a year\, yet solar energy contributes to only 2% of electricity 
 generation. This gap is due to the high price per watt of capture\, conver
 sion\, and retention. Solar panels capture direct sunlight\, but this depe
 nds on weather conditions. A fraction of light is converted into electrici
 ty as determined by the absorption bandwidth of silicon (Si). Electrical e
 nergy is then retained in batteries whose functionality is constrained by 
 the fermionic nature of electrons. These limitations on the electrical pro
 cess of harvesting solar energy motivate us to reconsider it as an optical
  process.\n\nIn this thesis\, we show that ambient light can be captured i
 nto confined modes\, retained by exploiting the bosonic nature of photons\
 , and also converted into kinetic energy of free electrons. Rather than co
 nverting energy from direct sunlight to bound electrons\, our novel scheme
  converts energy from ambient light to free electrons. It employs compleme
 ntary metal oxide-semiconductor technology to ensure inexpensive mass-manu
 facturability and leverages the maturity of the Si photonic (SiP) platform
  to design scale-invariant\, optical devices. We present this scheme as a 
 SiP circuit consisting of 6 devices which perform the following functions:
  (i) capture ambient light into confined modes\, (ii) split the modes base
 d on polarization\, (iii) rotate one polarization\, (iv) match the phases\
 , (v) combine them into a single mode\, and (vi) convert the energy to fre
 e electrons.\n\n(i) To capture ambient light\, we analyze the solar energy
  harvesting mechanisms of naturally occurring\, biosilica frustules in dia
 toms. We find that sub wavelength structures localized in the frustule pro
 duce a combined response to enhance optical capture\, redistribution\, and
  retention in the cell by 9.83%. This shows how the silica cladding of a S
 iP chip can enhance free-space coupling to the devices on-chip. (ii) To sp
 lit the fundamental transverse electric (TE0) and transverse magnetic (TM0
 ) modes\, we demonstrate an on-chip polarization beam splitter. Our design
  offers a high fabrication tolerance in a compact form factor resulting in
  an insertion loss of 2 dB and extinction ratio of 11.45 dB over a wavelen
 gth range of 1500-1600 nm. (iii) To rotate the TE0 mode towards TM0\, we d
 emonstrate an on chip electromagnetic coil which uses 14 mA of current to 
 generate an alternating magnetic flux density up to 1.16 mT inside a strip
  waveguide. We calculate a Faraday rotation of 34.65 pico-degrees at 1550 
 nm over an interaction length of 1097.4 μm. Our analysis also reveals ways
  to increase the rotation by orders of magnitude. (iv) To phase-match both
  polarization branches\, we design a dual polarization phase shifter to in
 duce the Pockels effect in an electro optic polymer. Simulations show a ph
 ase shift of 1.35 radians per 20 V over an interaction length of 8 mm. (v)
  The two branches are then combined (demonstrated but not included). (vi) 
 To convert light into electricity\, we design an on-chip device to maximiz
 e the overlap between an exposed TM0 supermode in a slot waveguide with co
 -propagating free electrons in an electron microscope. We optimize the cou
 pling efficiency over the interaction length to predict either an unpreced
 ented acceleration gradient of 3.81 GeV/m or an energy gain of 43.68 keV. 
 This increase in kinetic energy of the electron represents an increase in 
 electric current.\n\nOur novel device designs already offer direct applica
 tions to a variety of fields including telecommunications\, sensing\, and 
 quantum information science. Their separate applications incentivize furth
 er development\, which is supported by the modularized design of our circu
 it. Hence\, this thesis provides a starting point on the roadmap towards h
 arvesting solar energy on a SiP chip.\n
DTSTART:20221216T150000Z
DTEND:20221216T170000Z
LOCATION:\, Room 603\, McConnell Engineering Building\, CA\, QC\, Montreal\
 , H3A 0E9\, 3480 rue University
SUMMARY:PhD defence of Yannick D'Mello - Harvesting solar energy on a silic
 on photonic chip
URL:/ece/channels/event/phd-defence-yannick-dmello-har
 vesting-solar-energy-silicon-photonic-chip-344240
END:VEVENT
END:VCALENDAR