# Faculty

## Experimental Condensed Matter

(718) 997-3373, SB B212

Ph.D. Columbia University - 1973

PH 320W - Research & Writing in Science

PH 501 - Modern Aspects of Physics

PH 620W - Research & Writing Physics

## Research

For the last decade, Dr. Genack has been involved in the study of classical wave propagation in the presence of disorder. Both microwave (10 GHz to 20 GHz) and laser (630.8 nm) speckle patterns are studied in Dr. Genack's group. Some typical research projects are 1) 1-dimensional microwave system (10 GHz to 20 GHz); 2) quasi-1-dimensional microwave tube for speckle study (10 GHz to 15 GHz); and 3) He-Ne laser for deformed glass layers study.

Classical waves are the means by which we probe our environment and communicate with one another. As a result of wave - particle duality, studies of classical waves also serve as exacting models of electronic transport, involving quantum mechanical waves, in the solid state. One goal of studies at Queens College of optical and microwave radiation propagation is to provide a universal description of wave scattering in random systems. The Queens College group has demonstrated the relationship between the statistics of fluctuations of intensity and total transmission, non-local intensity correlation, and average transport in space, time, and frequency. This has provided essential models of electronic transport in mesoscopic systems, which are systems in which the phase coherence of the wave is preserved throughout the sample. Essential aspects of transport are described in terms of the degree of intensity correlation in space, which determines the closeness to the threshold for Anderson localization. Beyond the localization threshold, propagation is largely suppressed as a result of the interference of backscattered waves. The microwave laboratory was started in collaboration with Dr. Narciso Garcia. Many key measurements have been compared to theoretical calculations of Dr. A. A. Lisyansky and his students.

Among the milestones achieved in statistical studies have been the following: observations of short, long and infinite range intensity correlation in space and frequency; observation of the consequences of such correlation in producing marked and universal deviations of intensity and transmission distributions from their form for diffusive waves far from the localization threshold; observation of universal dynamical fluctuations in the dwell time of waves in random media; measurements of the statistical character of the transmitted field in the crossover from ballistic to diffusive propagation; creation of localized states in nearly periodic copper wire network filled with random mixtures of scattering particles; observations of resonances and in random media; and the inclusion of boundary effects to quantitatively describe transport. In addition acousto-optic tomography using diffuse light has been demonstrated, and Monte Carlo simulations of the random walk of photons in amplifying random media have established the incoherent nature of laser action in these systems.

In work carried out before coming to Queens College, Dr. Genack has demonstrated the diffusion of nuclear magnetism in superconductors, measured the spectrum of Wannier excitons in Cu_{2}O, demonstrated the use of photochemical hole burning to measure the homogeneous linewidth of molecules in solids, developed methods of coherent transient spectroscopy such as frequency and phase switching which have clarified the loss of coherence in atoms, molecules and solids, and has demonstrated that the origin of surface enhanced Raman scattering from molecules on metal surfaces is the resonant excitation of plasmons associated with surface roughness.

## Publications

- “Wave propagation and localization via quasi-normal modes and transmission eigenchannels,” J. Wang, Z. Shi, M. Davy and A. Z. Genack, Jour. Mod. Phys.: E-Conference Series.
- “Focusing through random media: eigenchannel participation number and intensity correlation,” M. Davy, Z. Shi and A. Z. Genack, Phys. Rev. B
**85**, 035105 (2012). - “Transmission Eigenvalues and the Bare Conductance in the Crossover to Anderson Localization,” Z. Shi and A. Z. Genack, Phys. Rev. Lett.
**108**, 043901 (2012). - “Chiral fibres: Adding twist,” V. I. Kopp and A. Z. Genack, Nature Photonics,
**5**, 470 (2011). - “Transport through modes in random media,” J. Wang and A. Z. Genack, Nature
**471**, 345-348 (2011). - “Mesoscopic speckle,” S. Zhang, Y. Lockerman and A.Z. Genack, Phys. Rev. E
**82**, 051114 (2010). - “Intensity statistics and photon localization in 1D and beyond,” J. Park, S. Zhang and A. Z. Genack, Phys, Rev. E
**82**, 045101 (R) (2010). - “Speckle statistics in the photon localization transition,” A. Z. Genack and J. Wang, in Int. J. Mod. Phys. B
**24**, 1950-1988 (2010). - “Speckle statistics in the photon localization transition,” A.Z. Genack and J. Wang, in 50 Years of Anderson Localization, ed. E. Abrahams, 559-597 (World Scientific, Singapore, 2010).
- “Chiral fiber sensors,” V.I. Kopp, V.M. Churikov, J. Singer, D. Neugroschl and A.Z. Genack, Proc. SPIE, 7677, 76770U (SPIE, Bellingham, WA, 2010).
- “Dynamics of fluctuations of localized waves,” J. Wang, A.A. Chabanov, D.Y. Lu, Z.Q. Zhang, and A.Z. Genack, Phys. Rev. B
**81**, 241101(R) (2010). - V.M. Churikov, V.I. Kopp, and A.Z. Genack, “Chiral diffraction gratings in twisted microstructured fibers,” Opt. Lett.
**35**, 342 (2010). - A.Z. Genack and S. Zhang, “Wave interference and modes in random media,” in Tutorials in Complex Photonic Media, eds. M. McCall, M.A. Noginov, N. Zheludev, and G. Dewar, Chapter 9, M. A. Noginov, M. W. McCall, G. Dewar, and N. I. Zheludev, Eds., SPIE Press, Bellingham, WA, 229–276 (2009).
- “Dual-twist fiber long period gratings,” V. M. Churikov, V. I. Kopp and A. Z. Genack, Proc. SPIE 7212, 72120H (2009),
- “Chiral fiber optical isolator,” V. I. Kopp, G. Zhang, S. Zhang, A. Z. Genack, D. Neugroschl, Proc. SPIE 7195, 71950B (2009).
- “Interplay between generic and mesoscopic speckle statistics in transmission through random media,” S. Zhang, Y. Lockerman, J. Park and A. Z. Genack, J. of Optics A: Pure and Applied Optics
**11**, 094018 (2009). - “Polarization properties of chiral fiber gratings,” G. Shvets, S. Trendafilov, V. I. Kopp, D. Neugroschl, and A. Z. Genack, J. Opt. A: Pure Appl. Opt.
**11**074007 (2009). - “Dynamics of localized waves: Pulsed microwave transmissions in quasi-one-dimensional media,” Z.Q. Zhang, A.A. Chabanov, S.K. Cheung, C.H. Wong, and A.Z. Genack, Phys. Rev. B
**79**, 144203 (2009). - “Chiral-fiber gratings sense the environment,” V.I. Kopp, V.M. Churikov and A.Z. Genack, Laser Focus World, page 76 (June, 2008).
- “Delocalization transition in dimensional crossover in random layered media,” S. Zhang, J. Park, V. Milner, A. Z. Genack, Phys. Rev. Lett.
**101**, 183901 (2008). - “Coupling and level repulsion in the localized regime: From isolated to quasi-extended modes,” K. Yu. Bliokh, Yu. P. Bliokh, V. Freilikher, A. Z. Genack, P. Sebbah, Phys. Rev. Lett.
**101**, 133901 (2008). - Statistics of random fields in the vortex core, S. Zhang and A. Z. Genack, Phys. Rev. Lett.
**99**, 203901 (2007). - Chiral fiber gratings: perspectives and challenges for sensing applications" V.I. Kopp, V.M. Churikov, G. Zhang, J. Singer, C.W. Draper, N. Chao, D. Neugroschl, and A.Z. Genack, Proceedings of SPIE 6619, 66190B (2007).
- Single and double helix chiral fiber sensors, V. I. Kopp, V. M. Churikov, G. Zhang, J. Singer, C. W. Draper, N, Chao, D. Neugroschl and A.Z. Genack, Jour. Opt. Soc. Am. B 24, A48 (2007).
- Effect of absorption on quasimodes of a random waveguide, P. Sebbah, B. Hu, V. I. Kopp, A. Z Genack, Jour. Opt. Soc. Am B 24, A77 (2007).
- Observation of singularities in multiply-scattered microwave fields, S. Zhang, B. Hu, Y. Lockerman, P. Sebbah, and A. Z. Genack, Jour. Opt. Soc. Am. A 24, A33 (2007).
- Speckle evolution of diffusive and localized waves, S. Zhang, B. Hu, P. Sebbah, and A. Z. Genack, Phys. Rev. Lett. 99, 063902 (2007).
- Conference Review: Meta 2006 highlights random, periodic optical metamaterials, V. M. Shalaev and A. Z. Genack, Laser Focus, 30 (August 2006).
- Localized Modes in Open One-Dimensional Dissipative Random Systems, K. Yu. Bliokh, Yu. P. Bliokh, V. Freilikher, A.Z. Genack, B. Hu, and P. Sebbah, Phys. Rev. Lett. 97, 243904 (2006).
- Quasimodes of spatially extended field distributions within nominally localized random waveguides, P. Sebbah, B. Hu, J. Klosner, and A. Z. Genack, Phys. Rev. Lett. 96, 183902 (2006).
- Synchronization of optical polarization conversion and scattering in chiral fibers, V. I. Kopp, V. M. Churikov, and A. Z. Genack, Opt. Lett. 31, 571 (2006).
- Signatures of photon localization, A. Z. Genack and A. A. Chabanov, J. Phys. A: Math. Gen. 38 10465-10488 (2005).
- Statistics of the Mesoscopic Field, A. A. Chabanov and A. Z. Genack, Phys. Rev. E 72, 055602 (2005).
- Statistics of the near-field speckle pattern in transmission through random media, P. Sebbah, B. Hu, A. A. Chabanov, and A. Z. Genack, in Complex Mediums VI: Light and Complexity, ed. by M. McCall and M. Noginov, Proceedings of SPIE vol. 5924 (SPIE, Bellingham, WA, 2005) p. 59240T.
- Electromagnetic fluctuations, correlation and localization in the time domain, A.Z. Genack, AA. Chabanov, B. Hu, Z.-Q. Zhang and P. Sebbah, in Complex Mediums VI: Light and Complexity ,ed. by M. McCall and M. Noginov, Proceedings of SPIE vol. 5924 (SPIE, Bellingham, WA, 2005) p. 592404.
- Optics: Waves in random media, A. Z. Genack, B. A. van Tiggelen, P. Sebbah and A. A. Chabanov, in Encyclopedia of Condensed Matter Physics, Elsevier (2005).
- Light Controllable Tuning and Switching of Lasing in Chiral Liquid Crystals, P V. Shibaev, R. L. Sanford, D. Chiappetta, V. Milner, A. Z. Genack, A. Bobrovsky, Optics Express 13, 2358 (2005).
- From planar to fiber chiral gratings, A. Z. Genack, V. I. Kopp, V. M. Churikov, J. Singer, N. Chao and D. Neugroschl, in Emerging Liquid Crystal Technologies, ed. by L.C. Chien, Proceedings of SPIE vol. 5742 (SPIE, Bellingham, WA, 2005) p. 90.
- Synchronization of optical polarization conversion and scattering in chiral optical fibers, V.I. Kopp, V.M. Churikov, and A.Z. Genack, Proceedings of SPIE vol. 5742 (SPIE, Bellingham, WA, 2005).
- Photon Localization Laser: Low-Threshold Lasing in a Random Amplifying Layered Medium via Wave Localization, V. Milner and A. Z. Genack, Phys. Rev. Lett. 94, 073901 (2005).
- Chiral fiber gratings polarize light, VI. Kopp, A.Z. Genack , V.M. Churikov, J. Singer, N. Chao, Photonics Spectra,
**38**, 78 (2004). - The Statistics of the Mesoscopic Field, A.A. Chabanov and A.Z. Genack , submitted (2004).
- Impact of weak localization on wave dynamics: crossover from quasi-1D to slab geometry, Z. Q. Zhang, S. K. Cheung, X. Zhang, A. A. Chabanov , and A. Z. Genack , to be published in Meth. and Appl. of Analysis (2004).
- Lasing and narrowing of spontaneous emission from responsive cholesteric films, P. V. Shibaev, J. Madsen and A. Z. Genack , Chem. Mater.
**16**, 1397-1399 (2004). - Chiral fiber gratings, VI. Kopp, V.M. Churikov, J. Singer, N. Chao, D. Neugroschl, and A.Z. Genack , Science
**305**, 74 (2004). - Dynamic correlation in wave propagation in random media, A. A. Chabanov , B. Hu, and A.Z. Genack , Phys. Rev. Lett.,
**93**, 123901 (2004). - Chiral fiber Bragg gratings, A.Z. Genack , V.I. Kopp, V.M. Churikov, J. Singer, N. Chao and D. Neugroschl, Complex Mediums V: Light and Complexity, ed. by Martin W. McCall and Graeme Dewar, Proc. of SPIE Vol. 5508 (SPIE, Bellingham, WA , 2004).
- Impact of weak localization in the time domain, S. K. Cheung, X. Zhang, Z. Q. Zhang, A.A. Chabanov , and A. Z. Genack , Phys. Rev. Lett.
**92**, 173902 (2004). - Polarization correlation in random media, A. A. Chabanov , A.Z. Genack, N. Tregoures and B.A. van Tiggelen, Phys. Rev. Lett.
**92**, 173901(2004). - Lasing from chiral photonic band gap materials based on cholesteric glasses, P.V. Shibaev, V.I. Kopp, A.Z. Genack, and E. Hanelt, Liq. Cryst.
**30**, 1391-1400 (2003). - Narrowing of spontaneous emission and lasing in lyotropic and thermotropic liquid crystals, P.V. Shibaev and A.Z. Genack, Liq. Cryst.
**30**, 1365-1368 (2003). - Photonic Materials Based on Mixtures of Cholesteric Liquid Crystals with Polymers, P.V. Shibaev, V.I. Kopp and A.Z. Genack, Jour. Phys. Chem. B,
**107**6961 (2003). - Double helix chiral fibers, V.I. Kopp and A.Z. Genack, Opt. Lett.
**28**, 1876 (2003). - Breakdown of diffusion in dynamics of extended waves in mesoscopic media, A.A. Chabanov, A.Z. Genack and Z.-Q. Zhang, Phys. Rev. Lett.
**90**, 203903-1 (2003). [APS link] - Lasing in chiral photonic structures, V.I. Kopp, Z.-Q. Zhang and A.Z. Genack, Prog. in Quant. Elec., to appear (2003).
- Photon localization in resonant media, A.A. Chabanov and A.Z. Genack in
*Wave Scattering in Complex Media,*ed by and B.A. van Tiggelen and S.E Skipetrov (Kluwer, Dordrecht , 2003). - Mesoscopic dynamics: a study of phase, A.Z. Genack, A.A. Chabanov, P. Sebbah and B.A. van Tiggelen in
*Wave Scattering in Complex Media,*ed by and B.A. van Tiggelen and S.E Skipetrov (Kluwer, Dordrecht, 2003). - Photonic Materials Based on Mixtures of Cholesteric Liquid Crystals with Polymers, P.V. Shibaev, V.I. Kopp and A.Z. Genack, to be published in Jour. Phys. Chem. B,
**107**6961 (2003). - Transmission through chiral twist defect in anisotropic periodic structures, V.I. Kopp, R. Bose and A.Z. Genack, Opt. Lett.
**28**, 349 (2003). - Photon localization in resonant media, A.A. Chabanov and A.Z. Genack, Optics and Photonics News,
**13**, 25 (2002). - Lasing from a stiff chain polymeric lyotropic cholesteric liquid crystal, P.V. Shibaev, K. Tang A. Genack, V.I. Kopp, M. M. Green, Macromolecules
**35**, 3022 (2002). - Twist defect in chiral photonic structures, V.I. Kopp and A.Z. Genack, Phys. Rev. Lett.
**88**, 033901 (2002). [APS] - Anisotropic Photonic Band Gap Structures, V.I. Kopp. P.V. Shibaev. R. Bose, and A.Z. Genack, Proc. SPIE,
**4655**, 141 (2002). - Spatial field correlation: the building block of mesoscopic fluctuations, P. Sebbah, B. Hu, A.Z. Genack, R. Pnini and B. Shapiro, Phys. Rev. Lett.
**88**, 123901 (2002). - Statistics of dynamics of localized waves, A.A. Chabanov and A.Z. Genack, Phys. Rev. Lett.
**87**, 233903 (2001). - Photon Localization in Resonant Media, A.A. Chabanov and A.Z. Genack, Phys. Rev. Lett.
**87**, 153901 (2001). [APS] - Large coherence area thin-film photonic stop-band lasers, V.I. Kopp, Z.-Q. Zhang and A.Z. Genack, Phys. Rev. Lett.
**86**__,__1753 (2001). [APS] - Statistical approach to photon localization, A.Z. Genack, A.A. Chabanov, in
*Waves and Imaging through Complex Media*ed. by P. Sebbah, p. 53-84 (Kluwer, Dordrecht, 2001). - Field and intensity correlation in random media, P. Sebbah, R. Pnini and A.Z. Genack, Phys. Rev. E
**62**, 7348 (2000). - Statistical approach to photon localization, A. A. Chabanov, M. Stoytchev, and A. Z. Genack, Nature
**404**, 850 (2000). - Spatial distribution of lasing at the edge of a photonic stop band in dye-doped cholesteric liquid crystals, V.I. Kopp, Z-Q Zhang, and AZ. Genack, Proc. SPIE Vol. 3939, p. 39-48, Organic Photonic Materials and Devices II, Donal D. Bradley; Bernard Kippelen; Eds. (2000)
- Observations of photon localization and exponential scaling of intensity fluctuations, A.Z. Genack and A. A. Chabanov, in
*Frontiers of Laser Physics and Quantum Optics*, ed. By Z. X. Xu, S. Xie, S-Y Zhu and M. O. Scully, p. 197-202 (Springer, 2000). - Delay-time statistics for diffuse waves, B.A. van Tiggelen, P. Sebbah, M Stoytchev, and A.Z. Genack, Phys. Rev. E
**59**, 7166 (1999). - Lasing at the edge of a photonic stop band in cholesteric liquid crystals, A.Z. Genack and V.I. Kopp, IEEE LEOS
**13**, 8 (1999). - Density of states and lasing at the edge of a photonic stop band in dye doped cholesteric liquid crystals, V.I. Kopp and A.Z. Genack, SPIE Proceedings vol. 3623,
*Organic Photonic Materials and Devices*(1999). - Statistics of wave dynamics in random media, A.Z. Genack, P. Sebbah, M. Stoytchev, and B.A. van Tiggelen, Phys. Rev. Lett.
**82**, 715 (1999). - Observations of non-Rayleigh statistics in the approach to localization, M. Stoytchev, A.Z. Genack, Opt Lett.
**24**, 262 (1999). - Fluctuations in photon local delay time and their relation to phase spectra in random media, P. Sebbah, O. Legrand and A.Z. Genack, Phys. Rev. E
**59**, 2406 (1999). - Low-threshold lasing at the edge of a photonic stop band in cholesteric liquid crystals, V.I. Kopp, B. Fan, H.K.M. Vithana, and A.Z. Genack, Opt. Lett.
**23**, 1707 (1998). - Multiple Scattering of Microwaves, P. Sebbah and A.Z. Genack, in New Aspects of Electromagnetic and Acoustic Wave Diffusion, Springer Tracts of Modern Physics, Vol.
**144**, p. 28 ed. by B. van Tiggelen, (Springer, Berlin, 1998). - Acousto-optic tomography with multiply scattered light, M. Kempe, M. Larionov, D. Zaslavsky, and A.Z. Genack, J. Opt. Soc. Am. A
**14**, 1151 (1997). - Ballistic and Diffuse Light Detection in Confocal and Heterodyne Imaging Systems, M. Kempe, A.Z. Genack, W Rudolph, and P. Dorn, J. Opt. Soc. Am. A
**14**, 216 (1997). - Dynamics of Stimulated Emission from Random Media Studied by Monte Carlo Simulation, G.A. Berger, M. Kempe, and A.Z. Genack, Phys. Rev. E
**56**, 6118 (1997). - Field Distributions in the Crossover from Ballistic to Diffusive Wave Propagation, A. Chabanov and A.Z. Genack, Phys. Rev. E
**56**, R1338 (1997). - Statistics of Cumulative Phase in Microwave Radiation in Random Media, P. Sebbah, O. Legrand. B. A. van Tiggelen and A.Z. Genack, Phys. Rev. E
**56**, 3619 (1997). - Measurement of the probability distribution of total transmission in random waveguides, M. Stoytchev and A.Z. Genack, Phys. Rev. Lett.
**79**, 309 (1997). - Microwave transmission through a periodic three-dimensional metal-wire network containing random scatterers, M. Stoytchev, A.Z. Genack, Phys. Rev. B
**55**, R8617 (1997). - Acousto-optic tomography with multiply scattered light, M. Kempe, M. Larionov, D. Zaslavsky, and A.Z. Genack, J. Opt. Soc. Am.
**14**, 1151 (1997). - Ballistic and Diffuse Light Detection in Confocal and Heterodyne Imaging Systems, M. Kempe, A.Z. Genack, W Rudolph, and P. Dorn, J. Opt. Soc. Am. A
**14**, 216 (1997). - Stimulated emission from amplifying random media, M. Kempe, G.A. Berger, and A.Z. Genack, in Handbook of Optical Properties, vol. 2; Optics of Small Particles, Interfaces and Surfaces, ed. R.E. Hummel and P. Wissmann (CRC Press, Boca Raton, 1997).
- Phase Statistics in Random Media, P. Sebbah, O. Legrand, and A.Z. Genack, OSA TOPS on Advances in Optical Imaging and Photon Propagation, Vol.
**2**, p. 386 ed. R.R. Alfano and J.G. Fujimoto (OSA, 1996). - Electromagnetic Resonances in Low Density Collections of Dielectric Spheres, M. Stoytchev, N. Garcia, and A.Z. Genack, Advances in Optical Imaging and Photon Propagation, ed. R.R. Alfano, (OSA, 1996).
- Confocal Spatial Filtering for Imaging with Ballistic Light in transillumination, M. Kempe, J. Wong and A.Z. Genack, Advances in Optical Imaging and Photon Propagation, (OSA, 1996).
- Intensity and Phase Distributions in the Transition from Ballistic to Diffusive Wave Propagation, A. Chabanov, M. Stoytchev, N. Garcia, and A.Z. Genack, Advances in Optical Imaging and Photon Propagation, ed. R.R. Alfano, (OSA, 1996).
- Acousto-Optic Imaging of Absorbing Structures with Multiply-Scattered Light, M. Kempe, M. Larionov, D. Zaslavsky, and A.Z. Genack, OSA TOPS on Advances in Optical Imaging and Photon Propagation, Vol.
**2**, p. 328 ed. R.R. Alfano and J.G. Fujimoto (OSA, 1996). - Time-Resolved Studies of Stimulated Emission from Colloidal Dye Solutions, M. Siddique, R.R. Alfano, G.A. Berger, M. Kempe, and A.Z. Genack, Opt. Lett.
**21**, 450 (1996)

**Facilities:**

**microwave facilities include:**

Hewlett Packard network analyzers from 50 MHZ - 40 GHz and from 50 MHZ - 40 GHz

Pulsed microwave spectrometer from 4-26 GHz with subnanosecond time resolution

Tektronix digital 11801B digital sampling oscilloscope

Wiltron 6759-B10 swept frequency synthesizer from 10 MHz - 26 GHz

Traveling Wave Tube Amplifiers

**laser facilities include**

Coherent Autoscan 899-29 high-resolution computer controlled tunable dye laser

Coherent Radiation argon ion-laser pumping swept single frequency dye laser

Quantronix YAG laser synchronously pumping mode locked, cavity dumped Coherent Radiation picosecond dye laser producing of 1 picosecond duration

Time correlated single photon detection apparatus with 30 picosecond time resolution

Princeton Instruments CCD detector camera for material imaging

Spex Industries Triplemate Spectrometer