Lab Affiliation(s):
Qing Hu, Vladimir Boluvic
Post Doc Sponsor / Advisor:
Vladimir Bulovic
Areas of Expertise:
  • Terahertz Quantum Cascade Lasers
  • Medical + Energy Technologies
  • Quantum Dot opto/electronics devices
Date PhD Completed:
September, 2012
Expected End Date of Post Doctoral Position:
September 8, 2014

Qi Qin

  • Post Doctoral

MIT Unit Affiliation: 

  • Electrical Engineering & Computer Science

Lab Affiliation(s): 

Qing Hu, Vladimir Boluvic

Post Doc Sponsor / Advisor: 

Vladimir Bulovic

Date PhD Completed: 

Sep, 2012

Top 3 Areas of Expertise: 

Terahertz Quantum Cascade Lasers
Medical + Energy Technologies
Quantum Dot opto/electronics devices

Personal Statement: 

As a MITer, I would like to dedicated my future research to applying electricial engineering discipline to solve problems in energy and medical fields. In this journey, the expertise aquired at MIT on terahertz photonics, nanotechnology and organic electronics will help me to achieve the goal.  

Expected End Date of Post Doctoral Position: 

September 8, 2014

CV: 

Research Projects: 

MIT Dept. of EECS, postdoc associate                                                10/2013--present

  • Conducted researches in large area display, light emitting diode and solar cell technologies.
  • Initiated the project to enhance light extraction efficiency of quantum dot LED and study of charge balance. 

MIT Dept. of EECS, Graduate Research Assistant                              2006 – 2012

  • Designed and built a mechanical positioning system in ultra-high vacuum and cryogenic condition with 100nm movement resolution.
  • First to modeled, designed and built tunable terahertz (THz) quantum cascade laser (This work resulted in a groundbreaking progress in THz research, published in Nature Photonics, featured in MIT home page, Nature Photonics: Review, and Photonics Focus).
  • Designed and fabricated a Microeletromechanical Systems (MEMS) based on Silicon-on-Insulator technology to achieve a record tuning range of THz QCLs(This work resulted in a broad media coverage including OSA.org, Reuters, ScienceDaily, Photonics Online and Terahertz Network)

Founder, Neuron One                                                                             10/2013—present

   Led commercialization of multimaterial fiber technologies applied as a medical device: steered the core business strategies, such as managing IP strategy, team dynamics, product development, market analysis, and strategic collaboration. 

   Managed recruitment and interviewing process of more than 30 physicians and researchers to obtain primary data for product definition and marketing case. Analyzed information from interviews and secondary marketing research to form new product and development strategies. 

Thesis Title: 

Development of tunable terahertz quantum cascade wire lasers

Thesis Abstract: 

For a long time, terahertz (THz) radiation has been of great interest to scientific community because of its spectroscopic and imaging applications based on its unique properties, such as the capabilities to penetrate many materials which are opaque in other frequency range (e.g. packaging, plastics, paints and semiconductors), and spectroscopic signatures of many important materials. In this thesis, a continuously tunable THz wire QC laser, which comprises a QC laser with deep sub-wavelength transverse dimensions, and a movable side object, termed as "plunger", is demonstrated. This deep sub-wavelength cross-section results in a large fraction of mode propagating outside of the laser core (GaAs/A1₀.₁₅Ga₀.₈₅As material system). The frequency tuning is achieved by changing the transverse wave vector, using a plunger made by metal (metal plunger) or silicon (dielectric plunger). When nudged close to the wire laser core, the metal plunger can push modes to the opposite side of the waveguide. Confined by a metal-metal waveguide, the mode is squeezed and the transverse wave vector is increased, resulting in a blue-shifted frequency. In contrast, a silicon plunger can suck the mode out due to its similar refractive index to GaAs/Al₀.₁₅Ga₀.₈₅As material system of laser core. Thus a decreased transverse wave vector results in a redshifted frequency. Although a tuning record of 138GHz (3.6%) was achieved, a discontinuous tuning resulted from a jittering movement of the plungers due to its friction with the guiding system. To solve this problem, an improved plunger based on micro-mechanical system (MEMS) was implemented. This MEMS plunger uses a two-stage folded-beam flexure to isolate the misaligned external actuation. The plunger is attached with the flexure which suspends above a silicon substrate to eliminate friction. Eventually, this MEMS flexure was actuated by a mechanical system which comprised a lever to de-amplify the displacement of a linear mechanical feedthrough. This MEMS plunger enabled a restorable and frictionless movement which led to a continuous tuning range of 330GHz (8.6%) centered at ~3.85 THz. The challenges posted by the weak mode discrimination led to the development of comb-shape connectors which electrically connect the top metal of wire lasers and the side bonding pad. This design can significantly increase the mode discrimination by selectively guiding undesired mode into the lossy bonding pad. This robust design of single mode operation enables the initial lasing at a frequency far below the gain peak, which can potentially increase the tuning range significantly.

Top 5 Awards and honors (name of award, date received): 

Semi-finalist (20 out of 1000 papers) of Maiman Paper Competition (2010)
People’s Scholarship of NJU 2002
Silver Medal of University Soccer League 2001

5 Recent Papers: 

1.      Qi Qin, N. Han, W. Kao, J. L. Reno and Q. Hu. “Effective mode selector for tunable terahertz wire-lasers,” Opt. Lett. 38, 407, 2013.

2.      S. Kumar, AWM Lee, Qi Qin, BS Williams, Q. Hu, J. L. Reno, “High-temperature performance and broad continuous tunability of terahertz quantum-cascade lasers”, Proc. SPIE, I9090, 2011

3.      Qi Qin, J. L. Reno and Q. Hu. “MEMS-plunger platform for tunable terahertz wire-laser at ~ 5 K,” J. Micromechanics and Microengineering, 21, 075004, 2011.

  1. Qi Qin, J. L. Reno and Q. Hu. “MEMS-based tunable terahertz wire-laser over 330 GHz”, Opt. Lett. 36, 692, 2011.
  2. Qi Qin, S. Kumar, B. S. Williams, Q. Hu, and J. L. Reno. “Tuning of Terahertz Wire Lasers”, Nature Photonics, 2009 3: 732 – 737

1.      Qi Qin, N. Han, W. Kao, J. L. Reno and Q. Hu. “Effective mode selector for tunable terahertz wire-lasers,” Opt. Lett. 38, 407, 2013.

2.      S. Kumar, AWM Lee, Qi Qin, BS Williams, Q. Hu, J. L. Reno, “High-temperature performance and broad continuous tunability of terahertz quantum-cascade lasers”, Proc. SPIE, I9090, 2011

3.      Qi Qin, J. L. Reno and Q. Hu. “MEMS-plunger platform for tunable terahertz wire-laser at ~ 5 K,” J. Micromechanics and Microengineering, 21, 075004, 2011.

  1. Qi Qin, J. L. Reno and Q. Hu. “MEMS-based tunable terahertz wire-laser over 330 GHz”, Opt. Lett. 36, 692, 2011.
  2. Qi Qin, S. Kumar, B. S. Williams, Q. Hu, and J. L. Reno. “Tuning of Terahertz Wire Lasers”, Nature Photonics, 2009 3: 732 – 737
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