Personal Information

1963:    Born:  September 5,  Bronx,  New York,  USA.
1990:    Married:  August 8,  Rina Danelia Trochez,  Bronx,  New York,  USA .

Education

1990:    B.S. in Physics,  City College of New York, NY,  USA.
1993:    M.S. in Physics,  University of California, Irvine, CA,  USA.
1999:    Ph.D. in Condensed Matter Physics, Imaging of Metallic Multilayer Structures Through   Nonequilibrium Electron Transport  
              and Energy Dynamics of Nonequilibrium Electrons in Thin Aluminum Films ,  University of California,  Irvine,  CA, USA.

Honors

1990:    Magna Cum Laude,  City College of New York, NY, USA.
1998:    Ph.D. Dissertation Fellowship, University of California, Irvine, CA,  USA.
1999:    NIH Post-Doctoral Fellowship, University of California, Irvine, CA, USA.
2006:    Voted "UCI Most Outstanding Professor in the School of Physical Sciences" by the graduating class of 2006.

Publications

1.    W. E. Bron, A. Guerra III, C. Suarez, "Imaging through quasi-particle transport." Optics Letters , 21, (1996) 997.
2.    W. E. Bron, A. Guerra III, C. Suarez, "Quasi-electron and phonon interactions in the femtosecond time domain." Journal of
        Luminescence , 76 &77 , (1998) 518.
3.    A. Melikyan, H. Minassian, A. Guerra III, W. Wu, "On the theory of relaxation of electrons excited by femtosecond duration  laser 
       pulses in thin metallic films." Applied Physics B, 68, no.3, (1999) 411.
4.    A. Guerra III, W. E. Bron, C. Suarez, "Imaging metallic multilayer structures through ultrafast optically driven excited electron
        transport." Applied Physics B, 68 , no.3, (1999) 405.
5.    A. Guerra III, V. Venugopalan, K. Nahen, A. Vogel, "Experimental investigation of optical breakdown using nanosecond 532- and
       1064-nm laser pulses delivered at high numerical aperture." Proceedings of SPIE , 4260 , 74 (2001). 
6.    V. Venugopalan, A. Guerra III, K. Nahen, A. Vogel, "The role of laser-induced plasma formation in pulsed cellular microsurgery
       and micromanipulation." Phys. Rev. Lett. 88 , Number 7, 078103 ( 2002). 
7.    K. Rau, A. Guerra III, A. Vogel, V. Venugopalan, "Investigation of laser-induced cell lysis using time-resolved imaging." Applied  
       Physics Letters, 84  , no. 15, (2004) 2940.

Research Interests

My research interests are focused on performing experiments that seek an undestanding of the interaction of ultrashort laser pulses with condensed matter, including biological tissues.

A.  Ph.D. Work   As a Ph.D. student working under the supervision of Prof. Walter E. Bron at UC-Irvine, I worked on ultrafast time-resolved experiments that allowed for the investigation of the dynamics and transport of excited (nonequilibrium) electrons in ultrathin metallic films.  The electrical and thermal conductivity (transport properties) of metals are critically influenced by electron scattering processes.  The advent of ultrafast laser systems permits investigations of the electron thermalization dynamics (and transport) in thin metallic films with femtosecond time resolution.  The experimental technique involves pulsed laser excitation at the "front" surface of a metallic film and detection of the evolution of the excitation by an appropriately time-delayed probe pulse incident at the "back" surface, as the schematic shown in figure 1 indicates.  The orange closed circles represent the excited electrons.

The duration of the pump and probe laser pulses is of the order of 100 fs.  The presence of excitations at the surfaces of the film produces changes in the optical constants (i.e. index of refraction)  which, in turn, induce changes in the optical reflectivity.  The incident pump pulse excites, to within the optical skin depth, electrons in the "front" surface of the film effecting, thereby,  their distribution among the energy states above (and below) the Fermi energy.  The excited electrons travel across the film and arrive at the "back" surface .  The transport of the excited electrons (also called quasiparticles) is driven by the quasiparticle concentration gradient originally created by the absorbed pump pulse between the excited and nonexcited volumes of the film.  We found that the theoretical basis for the analysis of the experimental data is best described by Landau's Fermi Liquid Theory.  It was also demonstrated that the transport of the excited electrons across thin metallic films can be used to generate "images" of the inner components of a multilayer structure composed of gold-titanium-gold thin films.  Figures 2 and 3 clearly show (in red) a titanium interlayer sandwiched between two layers of gold. The "front" layer of gold was 25 nm thick, the titanium interlayer consisting of two quares and one rectangle was 64 nmthick, and the "back" layer of gold was 26 nm thick.  Each titanium square was 1.0 mm on a side.
 
 

Figure 2.    The red areas represent regions of low transport electrons and correspond to a gold-titanium-gold multilayer. The blue
                       areas represent regions of high excited electron transport and correspond to a pure gold film only. 

Figure 3.    Rotated view of Figure 2.  
 

B.  Post-doctoral Work    As an NIH post-doctoral fellow, I  worked under the supervision of Prof. Vasan Venugopalan and Prof. Bruce Tromberg within the Laser Microbeam and Medical Program (LAMMP) at UC-Irvine.  LAMMP is located within the Beckman Laser Institute & Medical Clinic, an interdisciplinary biomedical research, teaching and clinical facility at UC-Irvine.   My participation in the LAMMP resource had two primary goals:

(a)  The first goal was to understand the underlying physical mechanisms, which enable a variety of pulsed cellular microsurgery and micromanipulation procedures.  Optical Breakdown is so far the number one suspect as the leading mechanism which drives such procedures.  We have completed the analysis of the data collected in a series of experiments on laser-induced breakdown in pure water.  These experiments were performed in Germany in collaboration with Prof. Alfred Vogel at the Medical Laser Center Lübeck. Our purpose was to investigate the laser parameters necessary to achieve laser-induced breakdown in pure water under nanosecond pulsed laser microbeam irradiation, and to compare these parameters with those used to perform intracellular surgery.  The results of this study strongly suggest that intracellular surgery relies on nonlinear absorption of photons leading to laser-induced breakdown at the focal volume of the laser beam.   I have integrated, with Dr. Kaustubh Rau, a time-resolved fluorescent microscopy system in order to investigate the dynamics of the molecular delivery process occurring in intracellular surgery such as optoporation and optoinjection.  Some pictures of the laser-induced plasmas and propagating shock wave are shown in figures 4 and 5 below.
 
 

                                                                         Figure 4.                                                                                Figure 5.

Figure 4.  Photographs of plasmas generated in pure water with pump pulse energies of 2x, 5x, and 10x threshold at 532 nm and at
                    1064 nm laser wavelengths.

Figure 5.  Photograph of plasma and shock wavefront 32 ns after generation with a pump pulse of energy 10x threshold and 1064 nm
                    center wavelength. The diameter of the shock wavefront is 144 micrometers .
 

(b)  The second goal  was to construct a laser interferometric system with high temporal and spatial resolution, suited for clinical diagnostic applications.  The interferometer is now being used to image bulk tissue phantoms by measuring the dynamic thermal expansion of the tissue surface resulting from the absorption of a nanosecond laser pulse.  More theoretical work needs to be done in order to correctly interpret the data collected with the interferometer.  The interferometer will soon be employed to image tissue heterogeneities with submillimeter resolution and at depths on the order of a centimeter.

In addition, I used my expertise in laser optics to further the development of the technology within LAMMP.  I participated a little bit in a collaborative effort to build a combined scanning Optical Coherence Tomography and Two-Photon Excitation microscope system.  The Optical Coherence Tomography (OCT) component will be used to provide information on the morphology of biological tissues, whereas the Two-Photon Excitation (TPE) component of the microscope will be used to provide information on the functionality of biological tissues.

I am very happy to have been a part of such an interdisciplinary group of distinguished scientists working in biomedical laser optics at the Beckman Laser Institute & Medical Clinic.  My participation in the LAMMP resource  provided me with a unique opportunity to build optical systems designed to investigate the dynamics and transport processes induced by high-intensity laser beams in biological tissues.  

Teaching Experience

1.    Physics Lab Instructor;  Resource Center for Science and Engineering;  City College of New York;  Summers of 1987, 1988, and
       1989.

2.     Physics Tutor and Assistant Coordinator;  Physics/Chemistry Learning Center;  City College of New York;  Jan. 1985 - Aug. 1990.

3.    Planetarium Shows Director;  Physics Department;  City College of New York;  Jan. 1987 - Aug. 1990.

4.    Physics Lab Instructor;  California Alliance for Minority Participation (CAMP);  University of California - Irvine;  Summers of
       1992 and 1993.

5.    Physics Instructor;  Kids Investigating and Discovering Science;  University of California - Irvine;  Summer of 1993.

6.    Physics Instructor;  California Alliance for Minority Participation;  University of California - Irvine;  Summers of 1994 - present. 

7.    Mathematics Instructor;  Saturday Science, Mathematics, and Technology Academy;  Willard Intermediate School;  Santa Ana
       Unified School District;  Feb. 3, 1996 - June 8, 1996.

8.    Physics Instructor; Middle School Summer Science, Mathematics, and Technology Academy;  University of California - Irvine;
       Aug. 5-23, 1996.

9.    Teacher of Series of 4 Workshops on Electricity and Magnetism to the gifted and talented students at John Adams Elementary
       School in Santa Ana, CA;  Jan. 30 - Feb. 18, 1997.

10.  Teacher of Series of 5 Workshops on Research Methodologies to the McNair/STAR students;  University of California - Irvine;
       Jan. 12 - Feb. 09, 1997.

11.  Teaching Assistant;  Department of Physics and Astronomy;  University of California - Irvine;  All Freshman Physics courses and
        Labs, Electricity and Magnetism, Quantum Mechanics, and Graduate Electromagnetic Theory; From Sept. 1990 - June 1999.

12.  Research Assistant;  Department of Physics and Astronomy; University of California - Irvine; From Jan. 1993 - June 1999.

13.  Calculus Instructor;  California Alliance for Minority Participation;  University of California - Irvine; Summers of 1998, and 1999.

14.  Physics Instructor;  Long Beach City College; Fall 1997, Spring 1998, Fall 1998, and Spring 1999.

15.  Physics Lecturer;  University of California - Irvine;  2000 - present.

16.  Physics Lecturer for MCAT review course, Postbaccalaureate Program, UCI Medical School,  1999, 2005, 2006, and 2007.

Presentations

1.    A. Guerra III, C. Suárez, W.E. Bron; “Imaging metallic multilayer structures through ultrafast optically driven  quasi-particle
       transport.”  Poster presented at the March Meeting of  The American Physical Society, March 18-22, 1996 in St. Louis, MO. 
       Vol. 41, No. 1. S36  9.

2.    A. Guerra III, C. Suárez, W.E. Bron; “Imaging metallic multilayer structures through ultrafast optically driven quasi-particle
       transport.” Poster presented at the Quantum Electronic Laser Sciences Conference (QELS ‘96), June 2-7, 1996 in Anaheim, CA.
       QTuB23.

3.    A. Guerra III, C. Suárez, W. E. Bron; “Imaging metallic multilayer structures through ultrafast optically driven excited electron
       transport.”  Graduate student Oral presentation given at the 1996 Annual Conference of the Society for The Advancement of
       Chicanos and Native Americans in Science (SACNAS), October 24-27, 1996 in Los Angeles, CA.
   
4.    A. Guerra III, W. Wu, W.E. Bron; “Quasiparticle Dynamics and  Transport in Thin Ferromagnetic Nickel Films.” Poster
       presented at the  March Meeting of  The American Physical Society,  March 16-20, 1998 in Los Angeles, CA. Vol. 43, No. 1,  I38 93.

5.    A. Guerra III, W.E. Bron, C. Suárez; “Imaging Metallic Multilayer Structures Through Ultrafast Optically Driven Excited
       Electron Transport.” Oral presentation given at the Nonlinear Optics at Interfaces Conference (NOPTI), September 21-24, 1998 
       in Berlin, Germany.

6.   A. Melikyan, H. Minassian, A. Guerra III, W. Wu;  “On the theory of relaxation of electrons excited by femtosecond duration laser
      pulses in thin metallic films.”  Poster presented at the March Meeting of  The  American Physical Society, March 20-26, 1999 in
      Atlanta, Ga. Vol. 44, No. 1, VP05  6.

7.   A. Guerra III, A. Vogel, K. Nahen, V. Venugopalan; “Optical breakdown using nanosecond laser pulses focused at high numerical
      aperture.” Poster presented at the United Engineering Foundation conference on Advances in Optics for Biotechnology, Medicine
      and Surgery. July 22-26, 2001 in Banff, Alberta, Canada.

8.    A. Guerra III, V. Venugopalan, K. Nahen, A. Vogel; “Is optical breakdown the mechanism driving the optoinjection of exogenous
       molecules into cells?” Oral presentation to be given at the XIV International Biophysics Congress, April 27 – May 1, 2002, Buenos
      Aires, Argentina. 

9.   A. Guerra III, V. Venugopalan, K. Nahen, A. Vogel; “Is optical breakdown the mechanism driving the optoinjection of exogenous
      molecules into cells?” Poster presented at the Gordon Conference on Lasers in Medicine and Biology, July 14-19, 2002, Kimball
      Union Academy, Meriden, New Hampshire. 

Professional Service

1.  Judge for the Physical Sciences Undergraduate Student Oral Presentation;  Third Annual National Science Foundation AMP
     (Alliance for Minority Participation) Research Conference; Held at The University of California - Irvine; July 31, 1995.

2.  Teaching Assistant chosen from the Physics Department to participate in the Student Parent Orientation Program (SPOP) held
     during the Summers of 1996, 1997, and 1998 at The University of California - Irvine.

3.  Judge for the Physical Sciences, Engineering, and Mathematics Poster Presentation; National conference of the Society for the
     Advancement of Chicanos and Native Americans in Science (SACNAS); Phoenix, Arizona; Sept. 27-30, 2001.

4.  Judge for the undergraduate oral/poster Presentations, state wide CAMP Symposium IV at the University of California - Riverside,
     February 2002, 2006.

5.  Judge for the UC-Edison Scholarship selection process for students transfering from a Community College to one of the 9 campuses
     of the University of California system.  July 2002.

Nuclear family Photographs