Seeing glass in a new light: Chalcogenide glass-enabled integrated photonics Juejun (JJ) Hu Materials Science & Engineering, MIT Juejun (JJ) Hu PMAT hujuejun@mit.edu
Former Members & Collaborators PMAT T @ Lan Li Tian Gu Derek Kita Hongtao Lin Jerome Michon Ying Pan Qingyang Du Kathleen Richardson Sarah Geiger Duanhui Li Anu Agarwal Shaoliang Yu Skylar Deckoff-Jones Carlos-Rios Ocampo Funding support Yifei Zhang Samuel Serna Mikhail Shalaginov Jun Qin Juejun (JJ) Hu PMAT hujuejun@mit.edu
Photonic Materials Research Group (PMAT) Nonreciprocal & nonlinear optics ACS Photonics 5 , 5010 (2018) Photon. Res. 6 , B37 (2018) Opt. Express 27 , 13781 (2019) On-chip Sensing 2-D material photonic integration Appl. Phys. Lett. 114 , 051103 (2019) Photon. Res. 6 , 506 (2018) Nat. Photonics 11 , 798 (2017) Nanophotonics 7 , 393 (2018) J. Opt. 20 , 044004 (2018) Chalcogenide photonics Flexible photonics Metasurfaces Nat. Photonics 8 , 643 (2014) Nat. Commun. 9 , 1481 (2018) Light Sci. Appl. 7 , e17138 (2018) Optica 5 , 44 (2018) Optical phase change materials Nat. Commun. (2019) Opt. Lett. 43 , 94-97 (2018)
Photonic Materials Research Group (PMAT) Nonreciprocal & nonlinear optics ACS Photonics 5 , 5010 (2018) Photon. Res. 6 , B37 (2018) Opt. Express 27 , 13781 (2019) On-chip Sensing 2-D material photonic integration Appl. Phys. Lett. 114 , 051103 (2019) Photon. Res. 6 , 506 (2018) Nat. Photonics 11 , 798 (2017) Nanophotonics 7 , 393 (2018) J. Opt. 20 , 044004 (2018) Chalcogenide photonics Flexible photonics Metasurfaces Nat. Photonics 8 , 643 (2014) Nat. Commun. 9 , 1481 (2018) Light Sci. Appl. 7 , e17138 (2018) Optica 5 , 44 (2018) Optical phase change materials Nat. Commun. (2019) Opt. Lett. 43 , 94-97 (2018)
ChGs enabling substrate-agnostic integration ☺ Epitaxy-free deposition ☺ Low deposition temperature B C N O F Weaker Al Si P S Cl inter-atomic bonds Ga Ge As Se Br In Sn Sb Te I Tl Pb Bi Po At Room temperature processing Juejun (JJ) Hu PMAT hujuejun@mit.edu
ChGs enabling substrate-agnostic integration ☺ Epitaxy-free deposition ☺ Low deposition temperature ☺ Versatile microfabrication Waveguide loss: Ge 23 Sb 7 S 70 0.5 dB/cm glass waveguide Cavity Q-factor: 1.2 × 10 6 2 µm Opt. Lett. 41 , 3090 (2016) Juejun (JJ) Hu PMAT hujuejun@mit.edu
ChGs enabling substrate-agnostic integration ☺ Epitaxy-free deposition ☺ Low deposition temperature ☺ Versatile microfabrication ☺ Chemical stability & inertness ChG can function as a passivation coating for 2-D materials Juejun (JJ) Hu PMAT hujuejun@mit.edu
R ~ 0.2 mm Juejun (JJ) Hu PMAT hujuejun@mit.edu
Making stretchable photonics out of rigid glass Grating coupler Devices on locally stiffened islands interconnected by serpentine waveguides Resonator Juejun (JJ) Hu PMAT hujuejun@mit.edu
Light Sci. Appl. 7 , e17138 (2018) ▪ Before 3000 cycles @ 42% ▪ After 3000 cycles @ 42% Juejun (JJ) Hu PMAT hujuejun@mit.edu
The world is not flat but rather 3-D Create 3-D photonics from planar structures via deterministic deformation Planar device 3-D structure Juejun (JJ) Hu PMAT hujuejun@mit.edu
3-D photonic fabrication 5 mm On substrate Delamination On stage 2 mm 3-D structure Tape removal After buckling Juejun (JJ) Hu PMAT hujuejun@mit.edu
A sensor for 3-D stress mapping in soft materials Collagen Fibers Fiber array block Device A 3-D stress sensor with force sensitivity down to 10 nN Photon. Res. 8 , 194-201 (2020) Juejun (JJ) Hu PMAT hujuejun@mit.edu
Photonic Materials Research Group (PMAT) Nonreciprocal & nonlinear optics ACS Photonics 5 , 5010 (2018) Photon. Res. 6 , B37 (2018) Opt. Express 27 , 13781 (2019) On-chip Sensing 2-D material photonic integration Appl. Phys. Lett. 114 , 051103 (2019) Photon. Res. 6 , 506 (2018) Nat. Photonics 11 , 798 (2017) Nanophotonics 7 , 393 (2018) J. Opt. 20 , 044004 (2018) Chalcogenide photonics Flexible photonics Metasurfaces Nat. Photonics 8 , 643 (2014) Nat. Commun. 9 , 1481 (2018) Light Sci. Appl. 7 , e17138 (2018) Optica 5 , 44 (2018) Optical phase change materials Nat. Commun. (2019) Opt. Lett. 43 , 94-97 (2018)
Photonic Materials Research Group (PMAT) Nonreciprocal & nonlinear optics ACS Photonics 5 , 5010 (2018) Photon. Res. 6 , B37 (2018) Opt. Express 27 , 13781 (2019) On-chip Sensing 2-D material photonic integration Appl. Phys. Lett. 114 , 051103 (2019) Photon. Res. 6 , 506 (2018) Nat. Photonics 11 , 798 (2017) Nanophotonics 7 , 393 (2018) J. Opt. 20 , 044004 (2018) Chalcogenide photonics Flexible photonics Metasurfaces Nat. Photonics 8 , 643 (2014) Nat. Commun. 9 , 1481 (2018) Light Sci. Appl. 7 , e17138 (2018) Optica 5 , 44 (2018) Optical phase change materials Nat. Commun. (2019) Opt. Lett. 43 , 94-97 (2018)
Photonic integration of 2-D materials relies on hybrid transfer Nature 474 , 64-67 (2011) Fabricated device 2-D layer transfer Hybrid transfer: Monolithic integration: ✓ Improved yield and × 2-D layer rupture at pattern edges throughput ✓ Flexible 2-D layer placement × Weak evanescent interaction ✓ Superior alignment accuracy × Limited throughput and integration capacity × Material degradation Juejun (JJ) Hu PMAT hujuejun@mit.edu
Thick dielectric growth on graphene is difficult due to its inert surface 3000 Prior to deposition 2500 After deposition 2 /Vs) 2000 Mobility (cm 1500 1000 500 0 SiO 2 TiO 2 × Direct dielectric deposition often results in defect formation which degrades graphene properties × Atomic layer deposition: low throughput for optical devices Juejun (JJ) Hu PMAT hujuejun@mit.edu
Compatibility of ChGs with graphene 2D G ChG maintains the structural and optoelectronic properties of graphene Nat. Photonics 11 , 798 (2017) Juejun (JJ) Hu PMAT hujuejun@mit.edu
Compatibility of ChGs with other 2-D materials MoS 2 Black phosphorus Hexagonal InSe BN Juejun (JJ) Hu PMAT hujuejun@mit.edu
ChGs as a passivation layer for 2-D materials The multifunctional ChG material Black phosphorus ✓ Broadband light guiding medium ✓ Passivation layer for 2-D materials ✓ Gate dielectric 30 nm Ge 23 Sb 7 S 70 glass film Nat. Photonics 11 , 798 (2017) Juejun (JJ) Hu PMAT hujuejun@mit.edu
Photonic Materials Research Group (PMAT) Nonreciprocal & nonlinear optics ACS Photonics 5 , 5010 (2018) Photon. Res. 6 , B37 (2018) Opt. Express 27 , 13781 (2019) On-chip Sensing 2-D material photonic integration Appl. Phys. Lett. 114 , 051103 (2019) Photon. Res. 6 , 506 (2018) Nat. Photonics 11 , 798 (2017) Nanophotonics 7 , 393 (2018) J. Opt. 20 , 044004 (2018) Chalcogenide photonics Flexible photonics Metasurfaces Nat. Photonics 8 , 643 (2014) Nat. Commun. 9 , 1481 (2018) Light Sci. Appl. 7 , e17138 (2018) Optica 5 , 44 (2018) Optical phase change materials Nat. Commun. (2019) Opt. Lett. 43 , 94-97 (2018)
Photonic Materials Research Group (PMAT) Nonreciprocal & nonlinear optics ACS Photonics 5 , 5010 (2018) Photon. Res. 6 , B37 (2018) Opt. Express 27 , 13781 (2019) On-chip Sensing 2-D material photonic integration Appl. Phys. Lett. 114 , 051103 (2019) Photon. Res. 6 , 506 (2018) Nat. Photonics 11 , 798 (2017) Nanophotonics 7 , 393 (2018) J. Opt. 20 , 044004 (2018) Chalcogenide photonics Flexible photonics Metasurfaces Nat. Photonics 8 , 643 (2014) Nat. Commun. 9 , 1481 (2018) Light Sci. Appl. 7 , e17138 (2018) Optica 5 , 44 (2018) Optical phase change materials Nat. Commun. (2019) Opt. Lett. 43 , 94-97 (2018)
Optical phase change materials (O-PCMs) Amorphous Crystalline Quench Anneal Covalent Resonant bonding bonding Index change D n > 1 Juejun (JJ) Hu PMAT hujuejun@mit.edu
Traditional O-PCMs (Ge-Sb-Te) are optically lossy Short l : Long l : Band-to-band Free carrier Free carrier absorption absorption (both a- & c-) (c- only) Band-to-band Optical losses in O-PCMs are bound by interband absorption at short wavelength and free carrier absorption at long wavelength Juejun (JJ) Hu PMAT hujuejun@mit.edu
GSST: an extreme broadband transparent phase change alloy 6 6 Ge 2 Sb 2 Se 4 Te 1 (GSST) Extinction coefficient k ✓ Index change: 5 5 Refractive index n D n = 1.7 – 2.1 4 4 ✓ Loss: k < 0.01 D n = 1.7 – 2.1 3 3 1 – 18.5 m m (a) 4 – 18.5 m m (c) 2 2 FOM 100x higher 1 1 than GST-225 k < 0.01 0 0 2 4 6 8 10 12 14 16 18 Nat. Commun. 10 , 4279 (2019) Wavelength ( m m) Juejun (JJ) Hu PMAT hujuejun@mit.edu
Free-space reflective light modulator pixel Patterned Metasurfaces Vdd 1 30 μm GSS4T1 2 Pulse 2 1 Subwavelength Pixels 30 μm 1 μm Nat. Commun. 10 , 4279 (2019) Juejun (JJ) Hu PMAT hujuejun@mit.edu
Switching of free-space reflective pixel 0.4 0.3 Reflectance 0.2 0.1 0.0 0 2 4 6 8 10 12 14 Time [s] 22% absolute Consistent 1,000 cycle reflectance contrast switching Juejun (JJ) Hu PMAT hujuejun@mit.edu
Electrically switchable metasurface based on GSST First demonstration of electrically switchable metasurface based on O-PCMs Juejun (JJ) Hu PMAT hujuejun@mit.edu
Switchable metasurface: multi-state operation 40 5 µs – 24.5 V Amorphous 9.5 V 11.3 V Increasing voltage 30 Reflectance (%) 20 Crystalline 500 ms – 10 variable voltage 0 Half-octave (480 nm) 1200 1300 1400 1500 1600 spectral tuning Wavelength (nm) Juejun (JJ) Hu PMAT hujuejun@mit.edu
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