公开(公告)号：US20180284492A1

公开(公告)日：2018-10-04

申请号：US15941879

申请日：2018-03-30

Applicant: Massachusetts Institute of Technology

Inventor： Zhuoran FANG ,  Tian GU ,  Juejun HU ,  Junying LI ,  Yifei ZHANG

IPC: G02F1/01 ,  G02F1/225 ,  C22C30/00 ,  C23C14/06

Abstract: An alloy of GexSbySezTem includes atoms of Ge, Sb, Se, and Te that form a crystalline structure having a plurality of vacancies randomly distributed in the crystalline structure. The alloy can be used to construct an optical device including a first waveguide to guide a light beam and a modulation layer disposed on the first waveguide. The modulation includes the alloy of GexSbySezTem which has a first refractive index n1 in an amorphous state and a second refractive index n2, greater than the first refractive index by at least 1, in a crystalline state. The first waveguide and the modulation layer are configured to guide about 1% to about 50% of the light beam in the modulation layer when the alloy is in the amorphous state and guide no optical mode when the alloy is in the crystalline state.

公开(公告)号：US20210025756A1

公开(公告)日：2021-01-28

申请号：US16928197

申请日：2020-07-14

Applicant: Massachusetts Institute of Technology

Inventor： Tian GU ,  Derek Kita ,  Juejun HU

IPC: G01J3/44 ,  G01J3/453 ,  G01J3/02 ,  G01N21/65

Abstract: State-of-the-art portable Raman spectrometers use discrete free-space optical components that must be aligned well and that don't tolerate vibrations well. Conversely, the inventive spectrometers are made with monolithic photonic integration to fabricate some or all optical components on one or more planar substrates. Photonic integration enables dense integration of components, eliminates manual alignment and individual component assembly, and yields superior mechanical stability and resistance to shock or vibration. These features make inventive spectrometers especially suitable for use in high-performance portable or wearable sensors. They also yield significant performance advantages, including a large (e.g., 10,000-fold) increase in Raman scattering efficiency resulting from on-chip interaction of the tightly localized optical mode and the analyte and a large enhancement in spectral resolution and sensitivity resulting from the integration of an on-chip Fourier-transform spectrometer.