Physical Optics and Electronics Group
Prof. Rajeev Ram

Major Research Themes:

Advanced Photonics

Provide new optical system functionality by exploiting novel physics from quantum interference to electron spin.


III-V devices are fabricated in the Microsystems Technology Lab clean rooms as well as the Nanostructures Lab clean room. Back-end device processing (facet cleaving, lapping, and bonding) is performed in the group laboratory. Fiber alignment stages, IR cameras, and tunable sources and optics are available for characterization of waveguide devices.


Huaiyu Meng and Karan Mehta


  1. K. K. Mehta, A. M. Eltony, C. D. Bruzewicz, I. L. Chuang, R. J. Ram,
    J. M. Sage, and J. Chiaverini. “Ion Traps Fabricated in a CMOS Foundry.” Applied Physics Letters 105, 044103 (2014). [PDF]
  2. Loh, William, Siva Yegnanarayanan, Rajeev Ram, and Paul Juodawlkis. “A Nonlinear Optoelectronic Filter for Electronic Signal Processing.” Nature Scientific Reports 4, 3613 (2014). [PDF]
  3. Mehta, Karan, Jason Orcutt, Ofer Tehar-Zahav, Zvi Sternberg, Reha Bafrali, Roy Meade, and Rajeev Ram. “High-Q CMOS-Integrated Photonic Crystal Microcavity Devices.” Nature Scientific Reports 4, 4077 (2014). [PDF]
  4. Mehta, Karan K., Jason S. Orcutt, and Rajeev J. Ram. “Fano Line Shapes in Transmission Spectra of Silicon Photonic Crystal Resonators.” Applied Physics Letters 102 (2013): 081109. [PDF]
  5. Santhanam, Parthiban, Dodd Joseph Gray, Jr., and Rajeev J. Ram. “Thermoelectrically Pumped Light-Emitting Diodes Operating above Unity Efficiency.” Phys. Rev. Lett. 108 (2012). [PDF]
  6. Summers, Joseph A., and Rajeev J. Ram. “Thermal and Optical Characterization of Resonant Coupling between Surface Plasmon Polariton and Semiconductor Waveguides.” Applied Physics Letters 99 (2011). [PDF]
  7. Loh, W., J. J. Plant, J. Klamkin, J. P. Donnelly, F. J. O’Donnell, and R. J. Ram. “Noise Figure of Watt-Class Ultralow-Confinement Semiconductor Optical Amplifiers.” IEEE Journal of Quantum Electronics 47.1 (2011): 66-75. [PDF]
  8. Zaman, T., X. Guo, and R. J. Ram. “Semiconductor Waveguide Isolators.” Journal of Lightwave Technology 26.2 (2008): 291-301. [PDF]

  9. Zaman, T., X. Guo, and R. J. Ram. “Faraday Rotation in an InP Waveguide.” Applied Physics Letters 90 (2007): 023514. [PDF]

  10. Zaman, T., X. Guo, and R. J. Ram. “Proposal for a Polarization Independent Integrated Optical Circulator.” IEEE Photonics Technology Letters 18.12 (2006): 1359-61. [PDF]

  11. Guo, X., T. Zaman, and R. J. Ram. “Faraday Rotation in Magneto-Optical Semiconductor Waveguides for Integrated Isolators.” Proceedings of SPIE 6124 (2006): 612416-7. [PDF]

  12. Fuchs, E., E. J. Bruce, R. J. Ram, and R. E. Kirchain. “Process Based Cost Modeling of Photonics Manufacture: The Cost Competitiveness of Monolithic Integration of a 1550nm DFB Laser and an Electro-Absorptive Modulator on an InP Platform.” IEEE Journal of Lightwave Technology 24.8 (2006): 3175-86. [PDF]

  13. Pipe, K. P., R. J. Ram, and A. Shakhouri. “Internal Cooling in a Semiconductor Laser Diode.” IEEE Photonics Technology Letters 14.4 (2002): 453-5. [PDF]
  14. Tepper, T., F. Illievski, C. A. Ross, T. R. Zaman, R. J. Ram, S. Y. Sung, and B. J. G. Stradler. “Magneto-Optical Properties of Iron Oxide Films.” Journal of Applied Physics 93.10 (2003): 6948-50. [PDF]
  15. Schmidt, H. and R. J. Ram. “All-Optical Wavelength Converter and Switch Based on Electromagnetically Induced Transparency.” Applied Physics Letters 76 (2000): 3173-5. [PDF]
  16. Patterson, S. G., E. K. Lau, K. P. Pipe, and R. J. Ram. “Temperature Characteristics of Bipolar Cascade Lasers.” Applied Physics Letters 77 (2000): 172-4. [PDF]
  17. Knodl, T., H. K. H. Choy, J. L. Pan, R. King, R. Jager, G. Lullo, J. F. Ahadian, R. J. Ram, C. G. Fonstad, Jr., and K. J. Ebeling. “RCE Photodetectors Based on VCSEL Structures.” IEEE Photonics Technology Letters 11 (1999): 1289-91. [PDF]
  18. Patterson, S. G., G. S. Petrich, R. J. Ram, and L. A. Kolodziejski. “X-ray Diffraction Analysis of Bandgap-Engineered Distributed Bragg Reflectors.” Journal of Electronic Materials 28 (1999): 1081-3. [PDF]
  19. Patterson, S. G., G. S. Petrich, R. J. Ram, and L. A. Kolodziejski. “Continuous-Wave Room Temperature Operation of Bipolar Cascade Laser.” Electronics Letters 35 (1999): 395-7. [PDF]


  1. K. Mehta, R.J. Ram, "Precise and diffraction-limited waveguide-to-free-space focusing gratings," Nature, Scientific Reports, 7, Article Number: 2019 (2017) (2017) DOI: 10.1038/s41598-017-02169-2 [PDF]
  2. K. Mehta, C. Bruzewicz, R. McConnell, R. J. Ram, J. Sage, J. Chiaverini, "Integrated optical addressing of an ion qubit," Nature Nanotechnology (2016) DOI: 10.1038/NNANO.2016.139 [PDF]
  3. N. Han, S. Cho, A. Atabaki, E. Ye, W. Herrington, R. J. Ram , "Non-paraxial Talbot Effect for Building Compact Spectrometers," Computational Optical Sensing and Imaging (COSI), Heidelberg, Germany (2016) [PDF]
  4. E. Ye, A. Atabaki, N. Han, R. J. Ram, "Miniature, sub-nanometer resolution Talbot spectrometer," Optics Letters, V. 41, 11 (2016): 2434-2437, [PDF]
  5. K. K. Mehta, A. M. Eltony, C. D. Bruzewicz, I. L. Chuang, R. J. Ram, J. M. Sage, and J. Chiaverini, "Ion Traps Fabricated in a CMOS Foundry," Applied Physics Letters 105, 044103 (2014) [PDF]
  6. W. Loh, S. Yegnanarayanan, R. J. Ram, P. Juodawlkis, "A Nonlinear Optoelectronic Filter for Electronic Signal Processing," Nature Scientific Reports 4, 3613 (2014) [PDF]