Microfluidics

Fluidic devices have been miniaturized over the past decades through the application of lithographic techniques and subsequent stamping or replication molding. The Caltech nanofabrication group has in the past worked with Professor Quake's group. As Professor Quake has taken a Professor position at Stanford University, the Microfluidics Foundry was integrated with the nanofabrication group, and more effort has been devoted to the development of both fluidic systems and thermal control systems. Most importantly, these devices have now been used in health-care applications through a collaboration with Emil Kartalov at the Norris Cancer center at the USC Keck school of Medicine. The most exciting areas of our recent fluidic advances include:

  1. The use of microfluidic systems for human blood serum analysis. Initial tests on the screening for common cancer markers show that it is possible to obtain similar accuracies and sensitivities within microfluidic systems as in conventional (and much more expensive) systems.
  2. The integration of microfluidics with nanophotonics for spectroscopy systems to determine concentrations of gases and ions in solution.
  3. The definition of some of the first microfluidic "dye lasers" that may enable low-cost tunable light sources.
  4. The development of new refrigeration systems based on micro-Peltier junctions and on evaporation systems. Very fast cooling rates in excess of 20C/second have been demonstrated in such systems and these have led to the development of nano-PCR systems that are presently evaluated.
  5. Three-dimensional fluidic systems have been designed and developed, and the traditional limitations of two-dimensional flow in multi-layer soft lithography devices (developed jointly between Professor Quake and Professor Scherer from 1997-2002) has now been overcome. One particularly interesting technique consists of wax molding using a wax-printer that has been recently adapted for fluidics within the Nanofabrication group.

The improvement of microfluidic control and the maturity of nanophotonic devices for spectroscopic applications now enables us to combine these two areas of our expertise to define new classes of chemical and biological sensors. To this combination, we intend to add electrical measurement and control systems in order to apply our technology to the most pressing medical and chemical sensor needs of today.

In one of the most exciting projects in collaboration with Professor Mladen Barbic, we are also developing magnetic techniques for read-out through nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) on a cellular scale. Our expectation is that opportunities will soon arise to integrate magnetic, optic and electronic sensors with fluidic delivery systems.

Technology transfer

Publications and patents have been written on all of the projects detailed above. An incomplete list of publications is summarized below, and a set of power-point slides is attached to describe some of the high-lites of the research areas within Professor Scherer's group. Naturally, some of the results from our work find their way to commercializable devices. One example of such an effort is the continued collaboration between Professor Scherer's group at Caltech and Luxtera. The Chief Technology Officer (CTO) at Luxtera, Dr. Lawrence Gunn, recently completed his studies in Professor Scherer's group, but the interaction between Caltech and Luxtera remains very active.

References

  1. Witzens J, Scherer A "Optoelectronics - Coupling lasers using photonic crystals", NATURE MATERIALS 4 (7): 512-513 JUL 2005
  2. Okamoto K, Niki I, Shvartser A, Narukawa Y, Mukai T, and Scherer A, "Surface plasmon enhanced super bright InGaN light emitter", Physica Status Solidi (c), Vol. 2, No. 7, pp. 2841-2844 (2005)
  3. Neal T.D, Okamoto K, Scherer A. "Surface plasmon enhanced emission from dye doped polymer layers", Optics Express, Vol. 13, No. 14, pp. 5522-5527 (2005)
  4. Maune B, Witzens J, Jones TB, et al. "Optically triggered Q-switched photonic crystal laser" OPTICS EXPRESS 13 (12): 4699-4707 JUN 13 2005
  5. Barbic M, Scherer A "Nanomagnetic planar magnetic resonance microscopy lens", NANO LETTERS 5 (4): 787-792 APR 2005
  6. Witzens J, Baehr-Jones T, Scherer A "Hybrid superprism with low insertion losses and suppressed cross-talk" PHYSICAL REVIEW E 71 (2): Art. No. 026604 Part 2 FEB 2005
  7. Witzens J, Scherer A, Pickrell G, et al. "Monolithic integration of vertical-cavity surface-emitting lasers with in-plane waveguides" APPLIED PHYSICS LETTERS 86 (10): Art. No. 101105 MAR 7 2005
  8. T. Baehr-Jones, M. Hochberg, C.A. Walker. A. Scherer, "High-Q optical resonators in silicon-on-insulator-based slot waveguides" APPLIED PHYSICS LETTERS 86 (8): Art. No. 081101 FEB 21 2005
  9. W.M.J. Green, R.K. Lee, G.A. DeRose, A. Scherer, A. Yariv. "Hybrid InGaAsP-InP Mach-Zehnder racetrack resonator for thermooptic switching and coupling control", OPTICS EXPRESS 13 (5): 1651-1659 MAR 7 2005
  10. J. Schilling, J. White, A. Scherer, G. Stupian, R. Hillebrand, U. Gosele, "Three-dimensional macroporous silicon photonic crystal with large photonic band gap" APPLIED PHYSICS LETTERS 86 (1): Art. No. 011101 JAN 3 2005
  11. W.M.J. Green, J. Scheuer, G.A. DeRose, A. Yariv, A. Scherer, "Assessment of lithographic process variation effects in InGaAsP annular Bragg resonator lasers", JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 22 (6): 3206-3209 NOV-DEC 2004
  12. Okamoto K, Zhang ZY, Wei DT, A. Scherer, "Photothermal molecular sensing by using metal thin-film nanograting for chemical and biomedical applications," THIN SOLID FILMS 469-70: 420-424 Sp. Iss. SI DEC 22 2004
  13. Okamoto K, Zhang ZY, Scherer A, et al. Mask pattern transferred transient grating technique for molecular-dynamics study in solutions APPLIED PHYSICS LETTERS 85 (21): 4842-4844 NOV 22 2004
  14. T. Yoshie, A. Scherer, J. Hendrickson, G. Khitrova, H. M. Gibbs, G. Rupper, C. Ell, O. B. Shchekin, and D. G. Deppe, "Vacuum Rabi splitting with a single quantum dot in a photonic crystal nanocavity," Nature 432, 200-203 (2004)
  15. J. Witzens, G. Pickrell, D. Louderback, P. Guilfoyle, A. Scherer, "Monolithic integration of vertical-cavity surface emitting lasers", Appl. Phys. Lett., 86, 101105-101105 3 (2005)
  16. M. Hochberg, T. Baehr-Jones, C. Walker, and A. Scherer, Integrated plasmon and dielectric waveguides, Opt. Express 12, 5481-5486 (2004)
  17. Okamoto K, Niki I, Shvartser A, Narukawa Y, Mukai T, Scherer A, Surface-plasmon-enhanced light emitters based on InGaN quantum wells NATURE MATERIALS 3 (9): 601-605 SEP 2004