Quantum Information Related Optics Research @ UBC Physics and Astronomy

1. Department of Physics and Astronomy University of British Columbia Quantum Information Related Optics Research @ UBC Physics and Astronomy Jeff Young et al. Kirk Madison et al. David Jones et al.

2. Three Principal Areas • Optical lattices (Kirk Madison) • Simulating complex quantum problems • Photonic crystal/quantum dot-based nonlinear optics (Jeff Young) • Towards QED on-a-chip • Phase-controlled laser sources (David Jones) • Coherent control

3. Quantum materials research with ultra-cold atomic gases Kirk Madison Theme: An ensemble of ultra-cold atoms held in optical potentials can be used to experimentally realize and study certain model Hamiltonians Directions: Realize N-body quantum systems of fundamental interest to condensed matter physics - low dimensional and/or strongly correlated systems - examples include • 1-D chains - (Luttinger liquids and Tonks gas) • 2-D and 3-D Hubbard (lattice) models with bosons and/or fermions Goal: study the behavior of various model Hamiltonians to determine the essential “ingredients” (terms in H) of new and/or unexplained phenomena - examples include • high-Tc superconductivity proof of principle : recent experimental realization of the Bose-Hubbard model What is its connection (if any) to the Fermi-Hubbard model?

4. Intensity = |E1 + E2|2 = I1 + I2 + 2(I1I2)1/2 cos[(k1-k2)•r] k2 E2 k1 periodicity d = l/2 sin(q/2) E1 in this example q = p , d = l/2 Periodic optical potentials are the analog of ionic crystal potentials - the optical-dipole potential experienced by an atom (AC stark shift) is proportional to the laser intensity - an intensity standing wave can be made by interfering two monochromatic lasers Designer Potentials: • the depth (intensity), position (phase), and periodicity (wave vectors) of the potential can be controlled by changing the properties of the interfering beams • the topography can also be changed by adding more beams • linear gradients can be added using external fields (gravitational, magnetic)

5. The connection to electronic condensed matter systems is by analogy analogous to electron atom optical lattice ionic crystal collisional interaction Coulomb interaction spatial rotations magnetic fields in some cases Notable differences: • optical lattices possess (almost) perfect crystal order no phonons, no impuries, no dislocations but “imperfections” can be added in... • the atoms considered here are neutral but mass ~ equivalent to charge d.o.f.

6. The connection to theoretical model systems is more direct proof of principle : recent experimental realization of the Bose-Hubbard model Greiner, Mandel, Esslinger, Haensch, and Bloch “Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms”, Nature 415, 39 (2002) new and relevant proposals to observe other effects with cold atoms abound Hofstetter, Cirac, Zoller, Demler, and Lukin “High-Temperature Superfluidity of Fermionic Atoms in Optical Lattices”, Phys. Rev. Lett. 89, 220407 (2002) A major contribution that experiments with ultra-cold atomic gases could make is to “bridge the gap” between models and real materials

7. Integrated (Nonlinear) Optical Circuits • Based on highly-evolved silicon-on-insulator and III-V semiconductor wafer processing technology (optical steppers, tight tolerances) • High-Q, ultra small volume microcavities defined by lithography and etching (ie. engineerable) • Integrate with artificial quantum dots to achieve nonlinear optics at the single photon level

8. Ideal Design Scenario… PC Inside Cavity Bend I/O Coupler Optical Transistor

9. SOI Sample Geometry 100 fs OPO (200 nm x 450 nm Si channels) Galian Photonics Inc.

10. Photoresist ~1 mm Si, 200 nm SiO2 1 mm Si substrate 2 mm Nanostructured Microcavity embedded in Single Mode SOI Waveguide Cowan, Rieger and Young, Optics Express (in press)

11. Bandgap of barriers |a> |b> Photonic crystal tunneling barriers |b> |a> 3D Microcavities in Waveguides Q~ 250

12. Photoresist ~1 mm Si, 200 nm SiO2 1 mm Si substrate 2 mm Add PbSe Quantum Dots to Enhance Nonlinear Susceptibility in Cavity

13. Soon to be Integrated Murray McCutcheon, in progress

14. Close Up

15. Q~10,000 FDTD Green’s Function

16. I () T() R() Minimize Switching Power Using 1D Waveguide + Nonlinear 0D Defect Cavity

17. Vmode=0.055 mm3 Lorentzian Bistability (no background) lb2/n2= 0, 0.1 & 0.4 Soljacic et al., PRE 66, 055601(R) 2002 Cowan and Young, PRE 68, 46606, 2003

18. Nonlinear Cavity Effect with QDots Q~1200 Pumped on resonance Transmission (a.u.) Pumped off resonance Energy (cm-1) Cowan, in progress

19. Optical Waveform Synthesis (David Jones) • Phase-stabilized fs lasers are used to engineer coherent electric field waveforms at optical (300-600 THz) frequencies with well-defined optical phases • Controlling the carrier-envelope phase (fCE) • Combined with pulse shaping techniques • Leads to… • Analog optical signal processing • Coherent control of atomic, molecular, and semiconductor systems • Designer (…and electric field coherent) optical pulses for selective probing of chemical reactions • Quantum information…? (very likely) f CE f f f f lens lens grating grating spatial light modulator (SLM) input pulse shaped pulse

20. LUX - Laser Systems Laser-based timing system - femtosecond x-ray pulses derived from laser pulses or laser-based RF Interconnected femtosecond laser systems - actively synched or seeded from master Maintain <100 fs synchronization - laser to laser synchronization - stabilized timing distribution network Master Oscillator Laser + RF HGHG FEL Seed Laser distribution network crab cavity Photo Injector Laser Multiple Beamline Endstation Lasers LINAC RF R. Schoenlein LUX Review 4/28/03

21. Summary • UBC Physics and Astronomy has a number of optical research activities that are directly relevant to quantum information technologies Acknowledgements: NSERC, CIAR, Galian Photonics Inc., CFI, BCKDF

22. Spectra: 800 mm Long Single Mode

23. 20:1 Negative Differential Transmission Using In-line Filter

24. Distribution of Time/Frequency Standards Time/frequency ? Plentywood Known time/frequency • How do you compare time/frequency? • Transport clock • via GPS/ two way satellite transfer • optical fiber link • Motivation for high stability time/frequency transfer • Comparison of optical standards for fundamental physics,… • Remote pulse synchronization: Laser and Linac http://bc1.lbl.gov/CBP_pages/CBP/groups/LUX/ • Surveillance • Telecom network synchronization Increase in stability