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Brochure Laser Research
Transcript of Lasercenter VU Amsterdam
l a s e r c e n t r e v u a m s t e r d a m
0002054/LaserBrchr/DEFINITIEF 06-05-2002 16:24 Pagina 1
3
Prof. Dr. W. Hogervorst (director)
Atomic and Laser Physics
Tel: 31-20-444 79 47
e-mail: [email protected]
Prof. Dr. S. Stolte
Physical Chemistry
Tel: 31-20-444 76 33
e-mail: [email protected]
Prof. Dr. D. Lenstra
Quantum Optics Theory
Tel: 31-20-444 78 55
e-mail: [email protected]
Prof. Dr. R. van Grondelle
Biophysics
Tel: 31-20-444 79 30
e-mail: [email protected]
Prof. Dr. C. Gooijer
Analytical Chemistry
Tel: 31-20-444 75 40
e-mail: [email protected]
Faculty of Sciences,
Vrije Universiteit Amsterdam,
De Boelelaan 1081-1083,
1081 HV Amsterdam NL
The Laser Centre Vrije Universiteit Amsterdam (LCVU) is a multi-disciplinary facility in which physicists, chemists
and biologists have combined their laser-oriented research activities. They share a common infrastructure of an
exceptionally well-equipped laboratory with state-of-the-art laser systems, auxiliary equipment and computer
facilities. A multitude of pulsed and CW laser systems in the infrared, visible, ultraviolet is available as well as a
facility for the generation of extreme ultraviolet radiation. Research activities, performed in a large number of
relatively small-scale experiments, vary from fundamental studies of atoms and molecules, laser cooling and
manipulation of atoms, dynamics of photosynthesis, chemical reaction dynamics and fluorescence spectroscopy of
bio-molecules to more applied studies of environmental trace analysis and atmospheric, bio-analytical and
photochemical chemistry. This makes LCVU an excellent place for visiting scientists from various disciplines.
How to reach Laser CentreVrije Universiteit?• from Schiphol Airport: train to
Amsterdam Zuid/World Trade Centre
(5 min), transfer to tram line 5, or
metro line 51, direction Amstelveen,
first stop is VU/De Boelelaan.
• from Amsterdam Central Station:
tram line 5 or metro line 51, direction
Amstelveen, exit at VU/ De Boelelaan.
• by car: city ring A10 (zuid), exit S108
Amstelveen, turn south, turn left after
about 200 meter to VU hospital on
the De Boelelaan, the University
Campus is next to the hospital.
l a s e r c e n t r e v u a m s t e r d a mDe Boelelaan
Laser Centre VU Amsterdam
0002054/LaserBrchr/DEFINITIEF 06-05-2002 16:24 Pagina 3
3
Prof. Dr. W. Hogervorst (director)
Atomic and Laser Physics
Tel: 31-20-444 79 47
e-mail: [email protected]
Prof. Dr. S. Stolte
Physical Chemistry
Tel: 31-20-444 76 33
e-mail: [email protected]
Prof. Dr. D. Lenstra
Quantum Optics Theory
Tel: 31-20-444 78 55
e-mail: [email protected]
Prof. Dr. R. van Grondelle
Biophysics
Tel: 31-20-444 79 30
e-mail: [email protected]
Prof. Dr. C. Gooijer
Analytical Chemistry
Tel: 31-20-444 75 40
e-mail: [email protected]
Faculty of Sciences,
Vrije Universiteit Amsterdam,
De Boelelaan 1081-1083,
1081 HV Amsterdam NL
The Laser Centre Vrije Universiteit Amsterdam (LCVU) is a multi-disciplinary facility in which physicists, chemists
and biologists have combined their laser-oriented research activities. They share a common infrastructure of an
exceptionally well-equipped laboratory with state-of-the-art laser systems, auxiliary equipment and computer
facilities. A multitude of pulsed and CW laser systems in the infrared, visible, ultraviolet is available as well as a
facility for the generation of extreme ultraviolet radiation. Research activities, performed in a large number of
relatively small-scale experiments, vary from fundamental studies of atoms and molecules, laser cooling and
manipulation of atoms, dynamics of photosynthesis, chemical reaction dynamics and fluorescence spectroscopy of
bio-molecules to more applied studies of environmental trace analysis and atmospheric, bio-analytical and
photochemical chemistry. This makes LCVU an excellent place for visiting scientists from various disciplines.
How to reach Laser CentreVrije Universiteit?• from Schiphol Airport: train to
Amsterdam Zuid/World Trade Centre
(5 min), transfer to tram line 5, or
metro line 51, direction Amstelveen,
first stop is VU/De Boelelaan.
• from Amsterdam Central Station:
tram line 5 or metro line 51, direction
Amstelveen, exit at VU/ De Boelelaan.
• by car: city ring A10 (zuid), exit S108
Amstelveen, turn south, turn left after
about 200 meter to VU hospital on
the De Boelelaan, the University
Campus is next to the hospital.
l a s e r c e n t r e v u a m s t e r d a mDe Boelelaan
Laser Centre VU Amsterdam
0002054/LaserBrchr/DEFINITIEF 06-05-2002 16:24 Pagina 3
Atomic and Laser Physics
Research is concerned with the interaction of laser light with atoms and molecules. This interaction can be used to
cool metastable helium atoms to ultra-low temperatures. With powerful lasers radiation at short wavelength is
generated using non-linear optical processes. The energetic photons are used to investigate atoms and small
molecules such as H2 and CO. Applied atomic and molecular spectroscopy and laser development are also part of
the group’s activities.
54
1 Doppler-free, high resolution spectroscopy is
performed on beams of rare-earth atoms. Rydberg
and autoionising states are populated in multi-step
excitation processes using pulsed or CW laser
systems.
2 Short-wavelength laser radiation can be generated
by focussing powerful, pulsed visible laser light in
a gaseous medium. Through a non-linear optical
process higher harmonics of the fundamental
radiation are produced. A bright source of
narrowband coherent radiation for high resolution
spectroscopy of atoms and molecules in the
wavelength range 50-200 nm is operational;
extension to 20 nm is pursued. With this source
some surprising new data on highly-excited, exotic
states of the H2 molecule have been obtained.
3-5 Large numbers of laser-cooled metastable helium
atoms can be stored in magneto-optical and magneto-
static traps. With the isotope 4He options to create a
macroscopic quantum state of matter (Bose-Einstein
condensate) are being explored. Further experiments
involve the realisation of an accurate atomic clock
based on laser-cooled 3He atoms, and new approaches
to build nano-scale structures with atom lithography.
1 2
4
3
5
0002054/LaserBrchr/DEFINITIEF 06-05-2002 12:21 Pagina 6
Atomic and Laser Physics
Research is concerned with the interaction of laser light with atoms and molecules. This interaction can be used to
cool metastable helium atoms to ultra-low temperatures. With powerful lasers radiation at short wavelength is
generated using non-linear optical processes. The energetic photons are used to investigate atoms and small
molecules such as H2 and CO. Applied atomic and molecular spectroscopy and laser development are also part of
the group’s activities.
54
1 Doppler-free, high resolution spectroscopy is
performed on beams of rare-earth atoms. Rydberg
and autoionising states are populated in multi-step
excitation processes using pulsed or CW laser
systems.
2 Short-wavelength laser radiation can be generated
by focussing powerful, pulsed visible laser light in
a gaseous medium. Through a non-linear optical
process higher harmonics of the fundamental
radiation are produced. A bright source of
narrowband coherent radiation for high resolution
spectroscopy of atoms and molecules in the
wavelength range 50-200 nm is operational;
extension to 20 nm is pursued. With this source
some surprising new data on highly-excited, exotic
states of the H2 molecule have been obtained.
3-5 Large numbers of laser-cooled metastable helium
atoms can be stored in magneto-optical and magneto-
static traps. With the isotope 4He options to create a
macroscopic quantum state of matter (Bose-Einstein
condensate) are being explored. Further experiments
involve the realisation of an accurate atomic clock
based on laser-cooled 3He atoms, and new approaches
to build nano-scale structures with atom lithography.
1 2
4
3
5
0002054/LaserBrchr/DEFINITIEF 06-05-2002 12:21 Pagina 6
Physical Chemistry
Research activities are mainly oriented towards a fundamental study of reactivity and energy transfer in chemical
dynamics. Processes of interest to atmospheric chemistry and surface science are studied at the state-to-state
quantum level of both reactants and products.
A broad range of femtosecond, nanosecond and continuous single-frequency laser systems is applied in
combination with molecular beam techniques to study and control chemical dynamics.
6
1
2
7
1 A cylindrical hexapole serves as a focusing
quantum state selector for polar molecules
by virtue of its high electric field gradients.
The selected molecules can then be oriented
with a uniform electric field to study the
effect of orientation on the outcome of a
collision with other molecules or atoms, or
on photolysis.
2 Angular and velocity resolved recoil of
fragments resulting from laser photolysis of
isotropic and oriented CX3Y reactant
molecules, such as CH3I.
3 4
3 A diode laser is externally injected with a
time-reversed feedback induced by phase-
conjugated reflection in a Rb vapour. At
a feedback level of only 10-3 a chaotic
coherence collapse is observed in the output
of the diode. The application of this type of
feedback to achieve GHz rate encrypted
optical communication is investigated now.
This experimental study is carried out in
close collaboration with the theoretical
quantum optics group.
4 Laser spectroscopy can elucidate highly-
excited molecular states on multiple
electronic surfaces. A conical intersection
between two potential surfaces may result
in a breakdown of the Born-Oppenheimer
approximation. The structure of the
hyperfine-resolved excitation spectrum
reveals the resulting electronically mixed
character of the NO2 eigenstates.
0002054/LaserBrchr/DEFINITIEF 06-05-2002 12:49 Pagina 8
Physical Chemistry
Research activities are mainly oriented towards a fundamental study of reactivity and energy transfer in chemical
dynamics. Processes of interest to atmospheric chemistry and surface science are studied at the state-to-state
quantum level of both reactants and products.
A broad range of femtosecond, nanosecond and continuous single-frequency laser systems is applied in
combination with molecular beam techniques to study and control chemical dynamics.
6
1
2
7
1 A cylindrical hexapole serves as a focusing
quantum state selector for polar molecules
by virtue of its high electric field gradients.
The selected molecules can then be oriented
with a uniform electric field to study the
effect of orientation on the outcome of a
collision with other molecules or atoms, or
on photolysis.
2 Angular and velocity resolved recoil of
fragments resulting from laser photolysis of
isotropic and oriented CX3Y reactant
molecules, such as CH3I.
3 4
3 A diode laser is externally injected with a
time-reversed feedback induced by phase-
conjugated reflection in a Rb vapour. At
a feedback level of only 10-3 a chaotic
coherence collapse is observed in the output
of the diode. The application of this type of
feedback to achieve GHz rate encrypted
optical communication is investigated now.
This experimental study is carried out in
close collaboration with the theoretical
quantum optics group.
4 Laser spectroscopy can elucidate highly-
excited molecular states on multiple
electronic surfaces. A conical intersection
between two potential surfaces may result
in a breakdown of the Born-Oppenheimer
approximation. The structure of the
hyperfine-resolved excitation spectrum
reveals the resulting electronically mixed
character of the NO2 eigenstates.
0002054/LaserBrchr/DEFINITIEF 06-05-2002 12:49 Pagina 8
98
Biophysics
Research in the Biophysics group is aimed at resolving basic (bio)physical concepts of photosynthesis, the process
by which green plants and algae efficiently convert light into chemical free energy. It is focused in particular on the
analysis of the first, extremely fast processes, which are studied using ultra-fast laser spectroscopy, ánd on the
relation between these fundamental processes and the molecular structure and biological function.
1 Photosynthesis takes place in membranes of chloroplasts. An electron
microscopic image of a paired photosynthetic membrane is shown, in
which several pigment-protein complexes can be observed.
2 Detailed electron-microscope image of a photosynthetic pigment-
protein complex. This complex (called photosystem 2) binds about 400
chlorophyll molecules that absorb light, transfer excitation energy and
induce a charge separation across the membrane on the time scale of
about one picosecond.
3 A synchroscan streak camera combined with a spectrograph monitors spectral and
temporal fluorescence changes of photosynthetic pigment-protein complexes with
about one picosecond time resolution. Ultrafast absorption difference changes can
be detected using the technique of pump-probe spectroscopy.
4 Fluorescence intensity as a function of time (vertical) and wavelength (horizontal) of
a photosystem 1 preparation after excitation by an ultrashort laser pulse. This
image, which covers a 200 ps time window and a 315 nm spectral window, is
obtained with a streak camera. Different colours represent different intensities.
5 Ultrafast spectroscopic measurements such as those obtained with a streak camera
are processed by global analysis. The so-called decay-associated spectra shown
reveal the dynamics of the migration of the excited electronic states through the
complex.
1 2 3 4 5
0002054/LaserBrchr/DEFINITIEF 06-05-2002 13:50 Pagina 10
98
Biophysics
Research in the Biophysics group is aimed at resolving basic (bio)physical concepts of photosynthesis, the process
by which green plants and algae efficiently convert light into chemical free energy. It is focused in particular on the
analysis of the first, extremely fast processes, which are studied using ultra-fast laser spectroscopy, ánd on the
relation between these fundamental processes and the molecular structure and biological function.
1 Photosynthesis takes place in membranes of chloroplasts. An electron
microscopic image of a paired photosynthetic membrane is shown, in
which several pigment-protein complexes can be observed.
2 Detailed electron-microscope image of a photosynthetic pigment-
protein complex. This complex (called photosystem 2) binds about 400
chlorophyll molecules that absorb light, transfer excitation energy and
induce a charge separation across the membrane on the time scale of
about one picosecond.
3 A synchroscan streak camera combined with a spectrograph monitors spectral and
temporal fluorescence changes of photosynthetic pigment-protein complexes with
about one picosecond time resolution. Ultrafast absorption difference changes can
be detected using the technique of pump-probe spectroscopy.
4 Fluorescence intensity as a function of time (vertical) and wavelength (horizontal) of
a photosystem 1 preparation after excitation by an ultrashort laser pulse. This
image, which covers a 200 ps time window and a 315 nm spectral window, is
obtained with a streak camera. Different colours represent different intensities.
5 Ultrafast spectroscopic measurements such as those obtained with a streak camera
are processed by global analysis. The so-called decay-associated spectra shown
reveal the dynamics of the migration of the excited electronic states through the
complex.
1 2 3 4 5
0002054/LaserBrchr/DEFINITIEF 06-05-2002 13:50 Pagina 10
11
Applied Laser Spectroscopy
Research is directed towards the development of molecular laser spectroscopic detection and identification
methods (Raman, fluorescence), coupled on-line to advanced separation techniques, to solve challenging
environmental problems and to study the interaction of small molecules with biopolymeric systems. Physical
chemistry of complex molecular systems is also a topic of fundamental research interest.
10
21 4
3
1 A challenging environmental problem is the elucidation of the
biodegradation routes of toxic compounds like polycyclic aromatic
hydrocarbons (PAHs) and their interaction with DNA or proteins in living
organisms. Special modes of fluorescence spectroscopy, e.g. fluorescence
line-narrowing (a cryogenic laser technique that provides detailed vibrational
patterns) can be used to identify PAH metabolites directly in small animals
like isopods (Porcellio scaber).
2 Raman spectroscopy is an analytical technique that can provide detailed
vibrational information for “fingerprint” identification. It is applicable to
aqueous samples, such as bioanalytical systems. The on-line combination of
Raman spectroscopy with high-performance separation techniques such as
column liquid chromatography is hampered by low sensitivity. This
limitation can be overcome with detector cells with an extremely long optical
path length. Such cells are based on liquid-core waveguides composed of
plastic materials with a refractive index lower than that of water, thus giving
total internal reflection.
3 Interfaces are being developed to couple spectroscopic identification techniques to liquid
chromatography (LC). Fluorescence line-narrowing spectroscopy is performed at cryogenic
temperatures (typically 10 K). Surface-enhanced resonance Raman spectroscopy requires the addition
of silver sol. Fourier-transform infrared spectroscopy requires removal of the aqueous phase. In the at-
line approach the chromatogram is deposited on a moving substrate, without loss of chromatographic
resolution, while the LC effluent is evaporated by means of a spray jet assembly. The separated spots
can then be analysed using the spectroscopic technique of choice.
4 Proteins, like cytochrome c, are prime examples of complex physico-chemical systems. The oxidation
states of the iron (grey) at the centre of the heme (red) are stabilized by subtle changes in the position
of the histidine (yellow) side chain. The function and properties are to a large extent determined by the
secondary (alpha helix) and the tertiary (folded) structure, which is shaped by genetic, and ultimately
evolutionary forces. A variety of linear and nonlinear optical techniques are used to study the structure
and dynamics of these systems. Emphasis is on temperature jump techniques to induce unfolding and
refolding of the protein, resonance Raman to study heme binding, and fluorescence energy transfer to
obtain information on intra- and intermolucular distances.
0002054/LaserBrchr/DEFINITIEF 06-05-2002 15:52 Pagina 12
11
Applied Laser Spectroscopy
Research is directed towards the development of molecular laser spectroscopic detection and identification
methods (Raman, fluorescence), coupled on-line to advanced separation techniques, to solve challenging
environmental problems and to study the interaction of small molecules with biopolymeric systems. Physical
chemistry of complex molecular systems is also a topic of fundamental research interest.
10
21 4
3
1 A challenging environmental problem is the elucidation of the
biodegradation routes of toxic compounds like polycyclic aromatic
hydrocarbons (PAHs) and their interaction with DNA or proteins in living
organisms. Special modes of fluorescence spectroscopy, e.g. fluorescence
line-narrowing (a cryogenic laser technique that provides detailed vibrational
patterns) can be used to identify PAH metabolites directly in small animals
like isopods (Porcellio scaber).
2 Raman spectroscopy is an analytical technique that can provide detailed
vibrational information for “fingerprint” identification. It is applicable to
aqueous samples, such as bioanalytical systems. The on-line combination of
Raman spectroscopy with high-performance separation techniques such as
column liquid chromatography is hampered by low sensitivity. This
limitation can be overcome with detector cells with an extremely long optical
path length. Such cells are based on liquid-core waveguides composed of
plastic materials with a refractive index lower than that of water, thus giving
total internal reflection.
3 Interfaces are being developed to couple spectroscopic identification techniques to liquid
chromatography (LC). Fluorescence line-narrowing spectroscopy is performed at cryogenic
temperatures (typically 10 K). Surface-enhanced resonance Raman spectroscopy requires the addition
of silver sol. Fourier-transform infrared spectroscopy requires removal of the aqueous phase. In the at-
line approach the chromatogram is deposited on a moving substrate, without loss of chromatographic
resolution, while the LC effluent is evaporated by means of a spray jet assembly. The separated spots
can then be analysed using the spectroscopic technique of choice.
4 Proteins, like cytochrome c, are prime examples of complex physico-chemical systems. The oxidation
states of the iron (grey) at the centre of the heme (red) are stabilized by subtle changes in the position
of the histidine (yellow) side chain. The function and properties are to a large extent determined by the
secondary (alpha helix) and the tertiary (folded) structure, which is shaped by genetic, and ultimately
evolutionary forces. A variety of linear and nonlinear optical techniques are used to study the structure
and dynamics of these systems. Emphasis is on temperature jump techniques to induce unfolding and
refolding of the protein, resonance Raman to study heme binding, and fluorescence energy transfer to
obtain information on intra- and intermolucular distances.
0002054/LaserBrchr/DEFINITIEF 06-05-2002 15:52 Pagina 12
Laser Centre Vrije Universiteit
Faculty of Sciences
De Boelelaan 1081-1083,
1081HV Amsterdam
The Netherlands
+31-20-444 78 90 (secretary)
+31-20-444 79 99 (FAX)
Internet:
http://www.nat.vu.nl/~laser/
http://www.chem.vu.nl
e-mail:
Production STAP TK&O, Amsterdam:
Pieter Kers and Ron Bergman, photography
Jean Trienes, design
Print:
Drukkerij Mart Spruijt BV, Amsterdam
0002054/LaserBrchr/DEFINITIEF 06-05-2002 16:15 Pagina 14
