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Raúl Baragiola, Engineering PhysicsResearch: Laboratory Astrophysics – optical characterization and simulation of micrometeorite impact via pulsed laser energy deposition.
Fellows:
Mark Loeffler - Simulation of micrometeorite impact on asteroids withpulsed laser beams. Characterization by FTIR andelectron spectroscopy
Devin Pugh - Characterization of thin film growth by diffuse laser scattering, interferometry, and microbalance techniques.Application to microporous amorphous ice.
Ben Teolis - Ultraviolet spectroscopy of ozone production incondensed gases by ion and photon irradiation.Application to icy satellites of Jupiter and Saturn.
Associates:Catherine Dukes, Jan Lorincik
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Mark Loeffler research on space weathering of asteroids
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Transient heating of olivine by laser pulse produces changes in near IR absorption bands similar to what is observed on asteroids, and attributed to the impact of micrometeorites and solar wind ions. XPS results show that irradiation forms iron precipitates. Unlike previous research, Mark will do reflectance measurements in situ, to prevent oxidation by air.
Electron microscopy will be used to understand the relationship between Fe nanoparticle size and distribution and the reddening of the mineral due to irradiation.
Lou Bloomfield, Dept. of PhysicsResearch: Dynamics of Cluster Structure, Isomerization, and Photodissociation.
Associates: Andy Dally & Songbai Ye
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Photodesorption of Alkali Negative Ions from Alkali-Halide Cluster
Anions
Using picosecond laser pulses, we have examined the photodesorption of negatively charged alkali ions from alkali-halide clusters. These fragile atomic ions, with extra electrons that are only barely held in place, have not been observed previously among the fragments leaving alkali-halide (salt) surfaces following exposure to light.
We find this unusual desorption in a broad class of negatively charge alkali-halide clusters—those containing two or more electrons that are not involved in the salt’s ionic bonding. The desorption starts via electronic excitation, with the excitation decaying quickly to eject the outgoing negative ion.
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Thermal Isomerization Dynamics and Melting in Alkali-Halide Clusters
We have produced (a) ensembles of cluster ions with enough thermal energy to undergo rapid changes in geometric structure, a process known as thermal isomerization. Because they switch quickly from one isomeric form to another, these clusters are effectively molten.
To study the dynamics of these clusters, we use an ultrashort laser pulse (b) to selectively destroy most of the clusters in one isomeric form. Thermal isomerization immediately begins to repopulate the missing form. We use a second laser pulse to measure the isomer populations at later times (c), and thus learn about the structure, energetics, and thermal properties of these tiny systems.
James Fitz-Gerald, Dept. of Materials Science and Engineering
Associate:Andrew Mercado - Matrix Assisted Pulsed Laser Evaporation (MAPLE) of Biodegradable Polymers: Excimer (ns) laser processing
Research: Laser based processing of organic and inorganic materials. In-situ plasma characterization, Materials characterization
• The volatile solvent absorbs a large % of the laser pulse. Upon heating, the solvent gently desorbs the organic molecule.
laser pulse
frozen target
volatile solvent is pumped away
substrate
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
012345678A
rb
itrary
ppm
Fluence: 0.30 J/cm2
Laser frequency: 20 Hz30,000 pulses
100 mTorr Ar, 60° tilt
100 nmSi wafer
Fluence: 0.43 J/cm2
Laser frequency: 20 Hz4,000 pulses
100 mTorr Ar
Fluence: 0.18 J/cm2
Laser frequency: 10 Hz10,000 pulses100 mTorr Ar
Fluence: 0.18 J/cm2
Laser frequency: 20 Hz21,000 pulses100 mTorr Ar
1 µm
1 µm
1 µm
(b)
(e)(d)
(c)
PLGA thin film
NMR spectra (a) comparing the native and deposited thin films and scanning electron microscopy (SEM) images of the deposited thin films (b-e). NMR spectra of the deposited films are in good agreement with the native material, with the exceptions as noted. SEM micrographs show trends in energy and deposition rate, both of which have a direct relationship to the entrainment process.
(a)
(PLGA)
CH3
OHO
1GA
CH3
O
OLA
[ OO
2
3 4[] ]Andrew Mercado’s Research on
MAPLE of a Biodegradable Polymer - PLGA
Thomas Gallagher, Dept. of PhysicsResearch: Interactions of Rydberg atoms with radiation fields and
with each other.
Fellows:Edward Shuman – Dielectronic Recombination in crossed static and
microwave fields.Ken Baranowski - Microwave ionization of alkali atoms.
Associate:Michael Bajema – Control of the branching ratio for autoionization with
the time delay between femtosecond laser pulses.
NSF IGERT: Science and Engineering of Laser Interactions with Matter
University of Virginia
Edward Shuman’s Research on Dielectronic Recombination
Dielectronic Recombination is the recombination of an ion and an electron via an autoionizing Rydberg state. It is enhanced by a static field below the classical limit, but does not occur above the classical limit. Adding a microwave field polarized perpendicular to the static field enables recombination above the classical limit. The mechanism is m transitions to more stable high m states.
Dielectronic Recombination signals with an 11 GHz field polarized perpendicular to a static field. The classical limit is the solid bold line. The signals above the classical limit are not present without the microwave field.
NSF IGERT: Science and Engineering of Laser Interactions with Matter
University of Virginia
0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
DR
sig
nal (
arb.
uni
ts)
-120-100 -80 -60 -40 -20 0
Relative binding energy (cm-1
)
0.09.919.729.738.548.858.467.078.588.397.6107.4118.7127.2137.8
Static electric field (V/cm
)
Tatiana Globus, Boris Gelmont, Dept. of Electrical and Computer EngineeringResearch:Terahertz Wave Interaction with Biological Macromolecules (Experiment + Modeling)
Fellow:Tiffany Mapp - Computer modeling of submillimeter wave absorption of short biological molecules.
Associate:Maria Bykhovskaia- Theoretical Prediction of Absorption Spectra.
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Tiffany Mapp’s Research on Computer Modeling of Submillimeter Wave Absorption
of Short Biological Molecules
Absorption spectra of double stranded RNA fragments Poly A-Poly U calculated for oscillator decay values =1 cm-1 and =0.5 cm -1 and for two different orientation of electric field of radiation relative to the long axes of a molecule.
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
THEORETICAL PREDICTION OF ABSORPTION SPECTRA
Torsion angles Frequencies<300 cm -1
Energy minimum Normal modes Spectra
Absorption Spectrum PolyAPolyU (z)= 1
Frequency (cm-1)
0 10 20 30 40 50 60
Abs
orpt
ion
0.000
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
Absorption of PolyAPolyU = 0.5
Frequency (cm-1)
0 10 20 30 40 50 60
Ab
sorp
tion
0.000
0.005
0.010
0.015
0.020
0.025
RNA Infra-red active modes have been calculated directly from the base pair sequence and topology of a moleculeSpectra are sensitive to a molecule’s compositionIntense peak is predicted at the lowest frequency ~ 2 cm-1.
() 2 (pk)2 / ( (k2 - 2 )2 + 2 2 )
Absorption spectra are calculated using the normalized dipole moment p
Ian Harrison, Dept. of ChemistryResearch: Laser induced photochemistry and spectroscopy at surfaces,
reaction dynamics of catalysis.
Fellows:Alex Bukoski - Microcanonical rate theory at surfaces: Application to
non-equilibrium laser, electron, and collisionally induced processes at surfaces.
Kristin Buck - Surface photochemistry and spectroscopy: Broadband ir/visible sum frequency generation,ultrafast photochemistry of adsorbates
Associates:Rob Zehr, Neel Samanta - Adsorbate photochemical dynamics: ns lasers.Todd Schwendemann - Electron transfer chemistry of single adsorbates studied by scanning tunneling microscopy.
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Alex Bukoski’s Research on Microcanonical Unimolecular Rate Theory at Surfaces
Dissociative chemisorption of a methane molecular beam incident on a Ni(100) surface with and without infrared laser excitation of the 3 antisymmetric C-H stretching vibration of the gas-phase CH4. Comparison of experiment to theory with different reaction threshold energies, E0.
Schematic depiction of the kinetics and energetics of activated dissociative chemisorption. Zero-point energies are implicitly included within the potential energy curve along the reaction coordinate.
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
CH4 : J = 2 , v3 = 1 Eigenstate
Tn = 400 K
Normal Translational Energy [kJ/mol]
20 30 40 50 60 70
Init
ial S
tick
ing
Co
effi
cien
t
10-7
10-6
10-5
10-4
10-3
10-2
10-1
PC - MURTE0 = 67 kJ/mol
E0 = 53 kJ/mol
Bob Jones, Department of PhysicsResearch: Investigating the response of atoms and small molecules to intense short laser pulses and the use of coherent light to view and control quantum dynamics in atoms and molecules
Fellows:Dan Pinkham - Characterization and control of ultra-fast laser pulse shapes for manipulation of intense field fragmentation processes in small molecules and clusters.Brett Sickmiller - Creation of sub-20 femtosecond VUV light pulses from intense near infrared light via high harmonic generation.
Associates:Merrick DeWitt, Eric Wells - Investigation of intense laser ionization and fragmentation in molecules and small clustersSantosh Pisharody, Jason Zeibel, Jeremy Murray-Krezan- Manipulation of electronic wavepackets for probing coherent time-dependent processes in atoms
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Pinkham/Well’s Research on Closed Loop Control of Intense Laser Fragmentation of Clusters
Typical results from a control experiment using S8 as a target. The left most columns show the S+ and S2+ product yields using an unshaped 100 fsec laser pulse. The middle and right hand columns show the same product yields when the algorithm is told to optimize the ratios S2+:S+ and S+:S2+, respectively.
Schematic of a closed loop laser control apparatus. A genetic algorithm searches for the “best” laser pulse to optimize a specified laser fragmentation pattern. The algorithm controls a liquid crystal based laser pulse shaper based on feedback from a fragmentation experiment .
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Transform S2
+ / S+ S+ / S2
+
S2+
Yie
ld
S+ Y
ield
3.6x
2.9x
0.0 1.0x10-5 2.0x10-5 3.0x10-5-0.02
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
Yie
ld
TOF
Laser
1 kHz800 nm120 fsec
James Landers, Dept. of ChemistryResearch: Analytical microchip technology for diagnostics and biomedical research.
Fellows:
James Karlinsey - Precision laser ablation of microstructures in glass chips - Acousto-optic technology development for laser-induced fluorescence detection on microchips
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
James Karlinsey’s Research on the Development of Microchip Technology
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Laser Machining with Femtosecond
Pulses: The SEM shows the exit plane of a microscope slide, after exposure to 2 mJ pulses fired at a 1 kHz repetition from a fs Regen laser focused at 250 mm. The laser-drilled has small dimensions (<100 µm) and will allow for microfluidic connects between different layers in a microdevice.
0
1
2
3
4
5
35 40 45 50 55 60 65
time/sR
FU
514 nm
488 nm 476 nm
457 nm
Multiline Ar+ Laser Scan: The RF applied to the AOTF was scanned from 100-180 MHz (~450-700 nm) at an interval of 0.5 MHz every 0.1 s. This offers new approaches for controlling the addressing of lasers on microchips.
Gabriel Laufer – Mechanical and Aerospace EngineeringResearch: Remote sensing of the distribution of CH4 in the
stratosphere and of oceanic chlorophyll from sounding rockets
Fellows:W. Clayton Nunnally- Wide Field of View Gas Filter Correlation Radiometer for Sounding Rocket Deployment
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Clayton Nunnaly’s research on measuring the stratospheric distribution of CH4
Absorption spectra of atmospheric CH4 and HCl, superimposed by the transmission curve of a spectral-limiting bandpass filter. By correlating this spectrum with the absorption by CH4 in a sample cell within the system, optical densities of 0.0001-0.001 atm-m can be measured at an uncertainty of <0.3% and FOV >30 while rejecting HCl interference.
Schematic of the solar gas filter correlation radiometer (GFCR). The system was designed to detect CH4 at high specificity using the absorption spectrum of solar radiation. A wide field of view (FOV) optical collection allows detection during rocket ascent without the need for active control.
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Stratospheric Absorbance 3.2-3.4 micronsTemp:233K Pressure: 0.01atm Path 50km
0.00E+00
2.50E-01
5.00E-01
7.50E-01
1.00E+00
3.46 3.38 3.31 3.24WL (m)
Ab
sorb
an
ce(1
-T)
Bandpass Filter CH4 HCL
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Microscale Heat Transfer LabProfessor Pamela Norris
Department of Mechanical and Aerospace Engineering
Research: • Observe transient carrier phenomena on a subpicosecond timescale using
non-destructive optical techniques.200 femtosecond laser in a pump-probe setup
• Contribute to the foundation for the continued development of nanoscale technologies.
Measure critical properties of metals and semiconductorsDevelop and verify models of transient carrier phenomena
• Fellow:Rob Stevens - Ultrafast carrier dynamics in a-Si:H and energy
transport in thin metallic films.
Rob Stevens’ Research on Ultrafast Carrier Dynamics in a-Si:H Films
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Chopper 500 HzPhotodetector
Prism on micropositioning
stage (0.1 m res.)
Pump:
1 kHz, ~100 fs, 625-1000nm, 20-120J
Probe:
1 kHz, ~100 fs, white light
Computer
Sample
Lock-in Amp
-1.2
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
-1 0 1 2 3 4 5 6
1.426 eV1.551 eV1.591 eV1.611 eV1.632 eV1.654 eV1.677 eV1.700 eV
T
/T
Time (ps)
Devising optical pump-probe techniques and models to better understand the transient carrier phenomena of a-Si:H films used by the photovoltaic industry. Primary focus is on recombination mechanisms and the role of band tail states.
Below is a series transmission scans of intrinsic a-Si:H collected using varying probe energies. The decays indicated by scans are a combination of thermalization of hot electrons, recombination, and trapping.
Brooks H. Pate, Dept. of ChemistryResearch: unimolecular isomerization kinetics, solvent effects on intramolecular vibrational dynamics, dynamic rotational spectroscopy
Fellows:Pam Crum (2nd Year) - Reaction dynamics in gas and solution by
selective-excitation, broadband probe ultrafast IR spectroscopy (ps pump - fs probe)
Kevin Douglass (2nd Year) - Time-domain 2D-Microwave spectroscopy of high-energy isomerization reactions (using
Fourier transform signal acquisition) Associates:John Keske (Ph.D. 2001) - Rotational spectroscopy of isomerizing
moleculesHyun Yoo (Ph.D. 2002) - Vibrational dynamics in gas and solutionYehudi Self-Medlin (Ph.D. 2003) - Vibrational dynamics and
isomerization in gas and solution
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
log(3330cm-1)0 1 2 3 4
Rat
e (1
011
s-1
)
0
1
2
3 IVRThreshold
kIVR (1011 s-1)0.0 0.5 1.0 1.5 2.0 2.5 3.0
k TO
T (1
011
s-1
)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
CCl4kVER = (67 ps)-1
kTOT = kIVR + kVER
Competition BetweenIntramolecular and Solution Dynamics
kTOT
kIVR 0 10 20 30 40 50Abs
orpt
ion
Cha
nge
(mO
D)
0
5
10
Time (ps)0 5 10 15 20
0
2
4Acetylenic CH Stretch
C6H5CCH
0 30 60 90 120 150
0
2
3 OH StretchCD3OH
OH Stretch(CF3)3COH
Direct Comparison ofGas- and Solution-Phase Dynamics
MW Frequency Scan to Measure303 - 202 Rotational Transition
Frequency (MHz)
26358.5 26359.5 26360.5
Inte
nsity
at P
eak
(V)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
FTMW 111 - 202 Excited
State Transition
Frequency (MHz)13647.10 13647.75 13648.40
Inte
nsity
(V)
0.0
0.1
0.2
0.3
0.4
Rotational Spectroscopy of Excited States by IR - FTMW - MW Triple Resonance Spectroscopy
Level Diagram for Fluoroproyne
FTMW Monitor(13647.75)
MW Scan
IR(3332.26 cm-1)
212
(JKaKc)
202
111
303 C
H
C
C
H
HF
Using the SELIM Ultrafast Laser Facility we have performed the first direct comparison of the isolated molecule and solution phase vibrational energy relaxation rates of polyatomic molecules. We find that solvent effects are minor and that the total relaxation rate in solution is dominated by the purely intramolecular dynamics. (Second plot: Gas (black), 0.05 M CCl4 solution (red))
The first measurements of the rotational spectrumof a laser-prepared vibrational excited state byFourier transform microwave (FTMW) spectroscopy is shown. This technique has also been extended to include IR-MW-MW triple-resonance measurements.
Vibrational Dynamics by Ultrafast Infrared Spectroscopy andDynamic Rotational Spectroscopy
Olivier Pfister, Dept. of PhysicsResearch: Quantum Optics and Quantum Information; experimental and theoretical studies of continuous-variable entanglement.
Fellows:
Raphael Pooser, 2nd year Engineering Physics student (Ph.D.)
- Theory of interferometry at the Heisenberg limit. - Design of a three-photon optical parametric oscillator and experimental investigation of its quantum and classical properties.
Gregory Jennings, 2nd year Material Science Engineering student (M.S.)
- Study and characterization of periodically poled nonlinear optical ferroelectrics.
Darrell Gullatt, 1st year Engineering Physics student (Ph.D.)
- Laser frequency stabilization and characterization.
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
QUANTUM OPTICS/QUANTUM INFORMATION Pfister Labs, UVa Physics
• Entanglement of two quantum optical fields: Quantum teleportation: “the disembodied transfer of an
unknown quantum state from one location to another” Ultra-precise interferometry at the Heisenberg limit:
measure optical phase
(N=photon number)
Time-domain: ultrasensitive detection of phase shifts (e.g. gravitational waves)
Space-domain: ultra-high-resolution quantum imaging / quantum lithography.
• Entanglement of three quantum optical fields: Quantum error correction and parallel quantum
communication (quantum telecloning).
k
r t 1
N 1
N
Cass Sackett, Dept. of PhysicsResearch: Laser cooling, Bose-Einstein condensation, and atom interferometry
Fellow:Jessica Reeves -Bose-Einstein condensation: Development of BEC machine, application to atom-interferometric measurement of inertial and interaction effects.
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
Jessica Reeves’s Research on Bose-Einstein Condensation and Atom Interferometry
Vacuum chamber constructed for BEC experiment. Currently trapping ~109 atoms at T ~ 50 K, and transferring atoms to UHV cell for further cooling.
Schematic depiction of atom interferometry with a Bose-Einstein condensate. A stationary cloud of atoms can be split into two pieces using laser manipulation, and later recombined. The atomic wave function will exhibit interference fringes that depend on the phase difference experienced.
NSF IGERT: Science and Engineering of Laser Interactions with MatterUniversity of Virginia
1
2
Suely Black, Department of Chemistry and CMR Research: Ab initio electronic structure modeling of infinite structures by van der Waals and covalent clusters
Fellows:Cheryl Blumenberg -Theoretical study of urea clusters structures and vibrational spectra using Hartree-Fock, DFT, and MP2 methods.Kendra Brown - Determination of the electrostatic potential of the hydrogen- terminated Si(100) 2x1 surface by ab inito methods for adsorption studies.Charmagne Harris - Calculation of the static first hyperpolarizabilities of methyl-nitroaniline (MNA) clusters.Associates:Chalette Sapp-Mobley - Theoretical study of the adsorption of MNA on the hydrogen-terminated Si(100) 2x1 surface.Sheena Inge - Application of semi-empirical/ab initio hybrid methods to model the Si(100) 2x1 surface.
NSF IGERT: Science and Engineering of Laser Interactions with MatterNorfolk State University
Blumenberg’s urea cluster structure determination using HF, DFT and MP2 methods
Clusters of up to seven urea molecules optimized with selected degrees of freedom to reproduce the crystal arrangement. Relative internal molecular coordinates are allowed to change. The OCNH dihedral angle decreases with increasing cluster size, approaching zero, which corresponds to the value found in the crystal.
NSF IGERT: Science and Engineering of Laser Interactions with MatterNorfolk State University
0
5
10
15
20
25
30
0 1 2 3 4 5 6 7 8
Allowed degrees of freedom in geometry optimization
Internal Dihedral Angle (º) OCNH, 6-31G** HF Optimized Geometries
# molecules in cluster
Carl Bonner, Department of Chemistry and CMR
Research: Investigating the 1st and 2nd order hyperpolarizability of molecular chromophores and polymers and the response transformation from individual molecules to clusters to films. Fellows:
LaQuita Huey – Measurement of two photon absorptivities in a range of thiacyanine analogues for optical limiting applications at Ti-Sapphire wavelengths
Associates:Olu Bolden - Characterization of 1st hyperpolarizbility of chromophores chiral or other tertiary structures, such as Ni-salophen (binapthol) compounds
NSF IGERT: Science and Engineering of Laser Interactions with MatterNorfolk State University
HyperRayleigh Scattering Measuerments of the 1st Hyperpolariability of Ni Salophen
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0
0
50
100
150
200
Slope = 3.8443 x 10-38
Slope = 1.05443 x 10-41
pNA reference DR-19
I 2/I
2 (ar
b un
its)
x 1
0-23
Number Density (particle/cm3) x 10
18
The dependence of the signal on concentration (expressed as number density) gives the molecular hyperpolarizbility. Measurements are made relative to a standard compound para-nitrobenzene.
Schematic of HyperRayleigh Scattering (HRS) experiment. The experiment measures the intensity of the second harmonic of the Rayleigh scattered line. This intensity is proportional to the square of the incident intensity. A confocal cavity maximizes the collection efficiency.
The signal is
I(2) = G i Ni<HRS2>i I()2
which for a two component system of solute and solvent is
=G[ Ns<HRS2>s + Nc<HRS
2>c ] I()2
NSF IGERT: Science and Engineering of Laser Interactions with MatterNorfolk State University
input
chopper
lens beamdump
Lock-in ampref
Ar+ ion pumped AmplifiedTi-Sapphire Laser, 800 nm
150 fsec, 250kHz, 4 J
ComputerBPF
PMT
IFattenuator
esu
0.0 0.5 1.0 1.5 2.0 2.5
0
3
6
9
12 Signal of 21 mM (V)
Signal of 12 mM (V)
Signal of 7 mM (V)
I(2
) (
Vol
ts)
I() (watt/cm2) x 1011
Mikhail A. Noginov Department of Physics and CMRResearch: The effect of the diameter of the pumped spot on the threshold and the slope efficiency of Nd0.5La0.5Al3(BO3)4 ceramic random powder lasers
Fellows:Kaleem J. Morris, MS student (directly supported by IGERT)
Associates:G. Zhu, MS student (not supported by IGERT directly)M. Bahoura, research faculty (not supported by IGERT directly)
NSF IGERT: Science and Engineering of Laser Interactions with MatterNorfolk State University
Study of random laser emission at different sizes of the pumped spot
Experimental setup
NSF IGERT: Science and Engineering of Laser Interactions with MatterNorfolk State University
0
0.02
0.04
0.06
0.08
0.1
0 10 20
Pumping energy (mJ)
1
2
3
0.1
1
10
100
0.001 0.01 0.1 1Diameter (cm)
Slope=1
Input/Output curves
Threshold density vs. spot diameter