| NSF Org: |
TI Translational Impacts |
| Recipient: |
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| Initial Amendment Date: | August 17, 2013 |
| Latest Amendment Date: | May 27, 2014 |
| Award Number: | 1330955 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Steven Konsek
TI Translational Impacts TIP Directorate for Technology, Innovation, and Partnerships |
| Start Date: | September 1, 2013 |
| End Date: | February 29, 2016 (Estimated) |
| Total Intended Award Amount: | $500,000.00 |
| Total Awarded Amount to Date: | $599,999.00 |
| Funds Obligated to Date: |
FY 2014 = $99,999.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
958 SAN LEANDRO AVE STE 100 MOUNTAIN VIEW CA US 94043-1996 (617)399-6405 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
381 Elliot St #140 L Newton MA US 02464-1159 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | SBIR Phase II |
| Primary Program Source: |
01001415DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.084 |
ABSTRACT
This Small Business Innovation Research (SBIR) Phase II project will demonstrate a prototype frequency tunable quantum cascade laser (TQCL) operating at terahertz frequencies (2-5 THz) for applications including gas spectroscopy and non-destructive imaging. This novel source is based on distributed feedback (DFB) terahertz QCL with a lateral waveguide dimension much smaller than the wavelength (wire laser). This optical mode extends outside the waveguide, allowing an external MEMS plunger to interact with the mode and affect tuning. A cryogenically operated motor is used to deflect the MEMS plunger allowing for electronic control of output frequency. A combination of mechanical electrical Stark shift tuning will allow frequency tuning range of >300 GHz with a resolution of 1 MHz. The output frequency of the TQCL will be coarsely calibrated allowing the output frequency to be selected in software. The TQCL will be housed in a small footprint cryocooler, and will have output powers greater than 100 µW.
The broader impact/commercial potential of this project will be in detection and characterization of narrow gas lines (MHz) or solid absorption features (GHz) in spectroscopy, remote sensing, astronomy and spectroscopic imaging. The innovation will be useful for academic, industrial and governmental research. The electrical operation of the MEMS tunable source and the turnkey nature of the cryogenic system will allow non-expert researcher access to the terahertz spectral region. Future uses include incorporation into a swept-source optical coherence tomography system for non-destructive evaluation (NDE). Terahertz frequency radiation is of particular interest for use in NDE because they are able to penetrate materials that are opaque at infrared and visible wavelengths such as structural foams, polymers and paints. Potential applications include the validation of the structural integrity of foams used in the aerospace industry, continuous monitoring of paint processes in the automotive industry, and the validation of pharmaceuticals tablet coatings used in controlled release formulations.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
This project has demonstrated a frequency tunable quantum cascade laser (TQCL) operating at terahertz frequencies (2-5 THz) for applications including gas spectroscopy and non-destructive imaging. In this frequency range, there is a dearth of tunable sources which can produce >10 uW of continuous wave output power, with a line width of <10 MHz – suitable for resolving low pressure vibrational-rotational lines for basic studies. The TQCL source is based on distributed feedback (DFB) terahertz QCL with a lateral waveguide dimension much smaller than the wavelength (wire laser). This optical mode extends outside the waveguide, allowing an external MEMS plunger to interact with the mode and affect tuning. To achieve this goal a recipe for the permanent and precise attaching of a silicon MEMS structure to a GaAs quantum cascade laser die was achieved. The micron level precision necessary for the aligment of the MEMS and GaAs pieces was achived with an in-house developed die attach machine. Once bonded, the combined MEMS/GaAs device survived repeated thermal cycling to cryogenic temperatures. To actuate the MEMS structure a cryogenically operated motor was demonstrated. The motor survived multiple thermal cyclings to cryogenic temperatures and demonstrated nanometer level positioning accuracy using an in-house developed cryogenic position sensitive detector (PSD) based encoder. To control the laser frequency, software was developed to control the position of the motor at cryogenic temperatures. This project resulted in a novel demonstration of continuous frequency tuning and is the broadest demonstration of electronically (software) controlled tuning in the terahertz frequency range to date. To increase the output power of the TQCL, a two stage, master-oscillator power-amplifier, configuration was demonstrated showing 3x amplification of the TQCL to power levels > 10 uW.
Last Modified: 06/01/2016
Modified by: Alan Lee
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