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公开(公告)号：US12158426B2
公开(公告)日：2024-12-03
申请号：US17999331
申请日：2021-05-20
Inventor： In-Cheol Jang , Benny Jian Rong Sng , Gajendra Pratap Singh , Rajeev J. Ram
Abstract: The present invention relates to the use of a Raman spectral signature for detection of plant metabolites, specifically carotenoids, in tissue of a plant leaf. Carotenoids are used as a biomarker for an early, real-time diagnosis of shade avoidance syndrome (SAS) in growing plants in a non-invasive or non-destructive way in order to detect the adverse effect of the SAS upon their health, and ultimately their yield. The early, real-time diagnosis of SAS provides a window period within which further adverse effects of SAS may be slowed or prevented without negatively affecting the yield of growing plants or leafy vegetables.
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公开(公告)号：US11756983B2
公开(公告)日：2023-09-12
申请号：US17765361
申请日：2021-12-10
Applicant: Massachusetts Institute of Technology
Inventor： Rajeev J. Ram , Jaehwan Kim , Jin Xue , Zheng Li
IPC: H01L27/15
CPC classification number: H01L27/156
Abstract: Light-emitting diodes having radiative recombination regions with deep sub-micron dimensions are described. The LEDs can be fabricated from indirect bandgap semiconductors and operated under forward bias conditions to produce intense light output from the indirect bandgap material. The light output per unit emission area can be over 500 W cm−2, exceeding the performance of even high brightness gallium nitride LEDs.
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公开(公告)号：US11605752B2
公开(公告)日：2023-03-14
申请号：US17032223
申请日：2020-09-25
Applicant: Massachusetts Institute of Technology
Inventor： Amir H. Atabaki , Rajeev J. Ram , Ebrahim Dakhil Al Johani
IPC: H01L31/105 , H01L31/0368 , H01L27/146
Abstract: Photodetectors using photonic crystals (PhCs) in polysilicon film that include an in-plane resonant defect. A biatomic photodetector includes an optical defect mode that is confined from all directions in the plane of the PhC by the photonic bandgap structure. The coupling of the resonance (or defect) mode to out-of-plane radiation can be adjusted by the design of the defect. Further, a “guided-mode resonance” (GMR) photodetector provides in-plane resonance through a second-order grating effect in the PhC. Absorption of an illumination field can be enhanced through this resonance.
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4.发明授权公开(公告)号：US12228518B2
公开(公告)日：2025-02-18
申请号：US17999312
申请日：2021-05-20
Inventor： Bong Soo Park , Rajeev J. Ram , Chung Hao Huang , Gajendra Pratap Singh , Nam-Hai Chua
Abstract: The present invention relates to the use of a Raman spectral signature of nitrate, as a biomarker for an early, real-time diagnosis of nitrogen status in growing plants in a non-invasive or non-destructive way in order to detect nitrogen deficiency before the onset of any visible symptoms. The early, real-time diagnosis of nitrogen deficiency in plants makes it possible to correct nitrogen deficiency for the avoidance of negative effects on the yield and biomass of growing plants or leafy vegetables.
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公开(公告)号：US11650440B1
公开(公告)日：2023-05-16
申请号：US17353081
申请日：2021-06-21
Applicant: Massachusetts Institute of Technology
Inventor： Marc De Cea Falco , Amir H. Atabaki , Rajeev J. Ram
IPC: G02F1/025 , G02F1/225 , H01L31/0745
CPC classification number: G02F1/025 , G02F1/2257 , H01L31/0745
Abstract: A photovoltaic modulator utilizes free carriers generated by absorption of optical radiation passing through the modulator to achieve ultra-low energy modulation of the radiation. The photovoltaic modulator can also function as an electro-optic transducer for low-power, low-EMI, high-density sensing applications.
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Patent Agency Ranking
公开(公告)号：US11307092B2
公开(公告)日：2022-04-19
申请号：US16853811
申请日：2020-04-21
Applicant: Massachusetts Institute of Technology
Inventor： Amir H. Atabaki , Rajeev J. Ram , William F. Herrington
IPC: G01J3/44 , G01J3/02 , G01J3/10 , G01J3/28 , G01J3/18 , G01N21/65 , G01J1/42 , G01J3/433 , G02B6/293
Abstract: In swept source Raman (SSR) spectroscopy, a swept laser beam illuminates a sample, which inelastically scatters some of the incident light. This inelastically scattered light is shifted in wavelength by an amount called the Raman shift. The Raman-shifted light can be measured with a fixed spectrally selective filter and a detector. The Raman spectrum can be obtained by sweeping the wavelength of the excitation source and, therefore, the Raman shift. The resolution of the Raman spectrum is determined by the filter bandwidth and the frequency resolution of the swept source. An SSR spectrometer can be smaller, more sensitive, and less expensive than a conventional Raman spectrometer because it uses a tunable laser and a fixed filter instead of free-space propagation for spectral separation. Its sensitivity depends on the size of the collection optics. And it can use a nonlinearly swept laser beam thanks to a wavemeter that measures the beam's absolute wavelength during Raman spectrum acquisition.
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公开(公告)号：US10533895B2
公开(公告)日：2020-01-14
申请号：US16244207
申请日：2019-01-10
Applicant: Massachusetts Institute of Technology
Inventor： Erika Ye , Amir H. Atabaki , Ningren Han , Rajeev J. Ram , William F. Herrington
Abstract: A non-paraxial Talbot spectrometer includes a transmission grating to receive incident light. The grating period of the transmission grating is comparable to the wavelength of interest so as to allow the Talbot spectrometer to operate outside the paraxial limit. Light transmitted through the transmission grating forms periodic Talbot images. A tilted detector is employed to simultaneously sample the Talbot images at various distances along a direction perpendicular to the grating. Spectral information of the incident light can be calculated by taking Fourier transform of the measured Talbot images or by comparing the measured Talbot images with a library of intensity patterns acquired with light sources having known wavelengths.
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公开(公告)号：US20190323892A1
公开(公告)日：2019-10-24
申请号：US16244207
申请日：2019-01-10
Applicant: Massachusetts Institute of Technology
Inventor： Erika Ye , Amir H. Atabaki , Ningren Han , Rajeev J. Ram , William F. Herrington
Abstract: A non-paraxial Talbot spectrometer includes a transmission grating to receive incident light. The grating period of the transmission grating is comparable to the wavelength of interest so as to allow the Talbot spectrometer to operate outside the paraxial limit. Light transmitted through the transmission grating forms periodic Talbot images. A tilted detector is employed to simultaneously sample the Talbot images at various distances along a direction perpendicular to the grating. Spectral information of the incident light can be calculated by taking Fourier transform of the measured Talbot images or by comparing the measured Talbot images with a library of intensity patterns acquired with light sources having known wavelengths.
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公开(公告)号：US11698301B2
公开(公告)日：2023-07-11
申请号：US17335299
申请日：2021-06-01
Applicant: Massachusetts Institute of Technology
Inventor： Rajeev J. Ram , Amir H. Atabaki , Nili Persits , Jaehwan Kim
CPC classification number: G01J3/0218 , G01J3/4412 , G01N21/65 , G01N2201/06113 , G02B6/4206
Abstract: Swept-source Raman spectroscopy uses a tunable laser and a fixed-wavelength detector instead of a spectrometer or interferometer to perform Raman spectroscopy with the throughput advantage of Fourier transform Raman spectroscopy without bulky optics or moving mirrors. Although the tunable laser can be larger and more costly than a fixed wavelength diode laser used in other Raman systems, it is possible to split and switch the laser light to multiple ports simultaneously and/or sequentially. Each site can be monitored by its own fixed-wavelength detector. This architecture can be scaled by cascading fiber switches and/or couplers between the tunable laser and measurement sites. By multiplexing measurements at different sites, it is possible to monitor many sites at once. Moreover, each site can be meters to kilometers from the tunable laser. This makes it possible to perform swept-source Raman spectroscopy at many points across a continuous flow manufacturing environment with a single laser.
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公开(公告)号：US11624941B2
公开(公告)日：2023-04-11
申请号：US17227457
申请日：2021-04-12
Applicant: Massachusetts Institute of Technology
Inventor： Rajeev J. Ram , Marc De Cea Falco , Jin Xue
IPC: G02F1/025
Abstract: Semiconductor optical modulators are described that utilize bipolar junction transistor (BJT) structure within the optical modulator. The junctions within the BJT can be designed and biased to increase modulator efficiency and speed. An optical mode may be located in a selected region of the BJT structure to improve modulation efficiency. The BJT structure can be included in optical waveguides of interferometers and resonators to form optical modulators.
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