| NATIONAL
INSTITUTE for LASER, PLASMA and RADIATION PHYSICS LABORATORY of SOLID-STATE QUANTUM ELECTRONICS |
|
TITLU:
Laseri de Tip Ghid de
Unda obtinuti prin Tehnica Scrierii Directe cu Pulsuri Laser cu durata
de
ordinul Femtosecondelor
TITLE:
Waveguide
Laser Devices Realized by Direct Femtosecond
Laser Writing Technique
___________________________________________________________________________________________________________________________________________________________________________
PROJECT
DURATION:
October 2011 - December 2016
DURATA
PROIECTULUI:
Octombrie 2011 - Decembrie 2016
PROJECT LEADER:
National Institute for Laser, Plasma
and Radiation
Physics, Magurele, Bucharest, Romania
CONDUCATOR PROIECT:
Institutul
National de
Cercetare-Dezvoltare pentru Fizica Laserilor, Plasmei si Radiatiei,
Magurele,
Bucuresti, Romania
Contract value: 1.500.000 lei
Valoare contract: 1.500.000 lei
The research team: PAVEL Nicolaie, PhD
Echipa de cercetare: DASCALU Traian, PhD
ZAMFIRESCU Marian, PhD
SALAMU Gabriela, PhD student
GRIGORE Oana Valeria, PhD student
VOICU Flavius Marian, PhD student
JIPA Florin, PhD student
___________________________________________________________________________________________________________________________________________________________________________
●
The ability of
ultra-short laser pulses to induce
permanent changes on the refractive index of solid-state laser media is
nowadays attracting much attention because of the unique possibility of
three-dimensionally
modifying, at the micrometric and sub-micrometric scale, the optical
properties
of the irradiated media. The interest is of both fundamental and
applied point
of view. One of the most promising, but also challenging applications
of this
technique, is the integrated laser active optical circuit fabrication.
When
femtosecond (fs) pulses are focused inside the bulk media, permanent
(micro-) modifications around the focus region are induced; these
changes can lead to the
creation of buried channel waveguides. On the other hand, material
removal can
take place if the fs pulses are focused at surface, which could lead to
the
appearance of a surface channel waveguide close to the ablated volume.
A
variety of optoelectronic components, such as photonic crystals,
diffraction
grating, or optical memories can be fabricated by this
technique.
●
One very
interesting application of fs direct laser
writing is fabrication of buried channel waveguide lasers. For lasers
applications, channel waveguides can be used to confine tightly the
pump and
laser modes and to achieve a high spatial overlap. Furthermore,
waveguide confinement
can provide lower lasing thresholds and higher pumping efficiencies
than are
obtainable in bulk laser counterparts. Therefore, due to their robust
monolithic
nature, waveguide lasers arebecoming potential candidates as efficient
laser
sources for integrated optics. Nd-lasers are
promising active media for waveguide
lasers with low threshold, high efficiency, and rather high (watt- or
few-watts
level) power in continuous wave operation regime.
●
The
main objectives
of this project are:
A. Realization
of waveguide lasers by fs direct laser writing;
B.
Demonstration
of laser emission in
such structures at the fundamental wavelength of emission, as well as
in
visible spectrum employing multi-functional optical waveguides;
C.
Evaluation
of various phenomena, like spatial location, magnitude and nature of
the
micro-structural and refractive index changes, or modification of laser
media
spectroscopic properties that takes place during and after the process
of
waveguide writing, the investigations aim being theoretical modeling
and
explanation of these phenomenon.
●
Theoretical substantiation.
Experimental conditions for fs-laser beam direct writing in Nd:YAG.
●
Nd-based
waveguide lasers obtained by direct writing with fs Ti:sapphire
laser in single-crystals gain media.
●
Waveguide lasers based on
all-poly-crystalline Nd:YAG ceramics.
●
Waveguide lasers in Nd-vanadates.
5.
STAGE V. December 2015:
●
Multi-functional
optical waveguides. Passively Q-switched waveguide lasers.
6.
STAGE V.
September 2016:
●
Multi-functional
optical waveguides. The final research report.
___________________________________________________________________________________________________________________________________________________________________________
RESULTS
___________________________________________________________________________________________________________________________________________________________________________
1. STAGE I. October - December 2011
Value:
41.000 lei
●
Theoretical
studies aiming writing of waveguides in Nd-based lasers have been
conducted. The characteristics of the laser crystals that will be used
in experiments have been determined.
●
Raportul
stiintific pe anul 2011 este disponibil aici: | 2011
|
___________________________________________________________________________________________________________________________________________________________________________
2. Stage
II. December 2012
Value:
570.000 lei
OBJECTIVES
1.
Realization of waveguides in Nd:YAG single crystals by direct writing
with fs-laser technique.
2. Laser emission at 1.06 si 1.32 µm
under diode pumping at 807 nm.
3. Preliminary experiments aiming wrinting of
waveguides in Nd-vanadate laser crystals.
4. Development of a technique for obtaining ceramics Nd:YAG laser media
(preliminary experiments).
RESULTS
●
Waveguides
have been inscribed in Nd:YAG single crystals. Various kind, such
as two-wall types, and buried cladding depressed structures of
rectangular, square, circular or ellipse shapes were
realized. The
minimal fluence of the Ti:sapphire laser for writing these waveguides
was 3.4 J/cm2.
The waveguides losses were in the range of 1.1-1.4 dB/cm for
the
two-wall type waveguides, and from 1.3 to 2.2 dB/cm for the
buried
cladding depressed wavequides.
●
Laser emission at 1.06 and 1.34 µm has been achieved using the pump
with diode lasers at 807 nm
as follows:
- Laser pulses at 1.06 µm (randomly-polarized
beam) with energy of
1.8 mJ (overall optical-to-optical efficiency of 20%) were obtained
from a buried
cladding depressed wavequides with radius of
120 µm. The same waveguide yielded 0.54 W
of continuous-wave power
(optical-to-optical efficiency of 14%). A two-wall type waveguide
(40 µm distance between) delivered
linearly-polarized pulses with 0.92 mJ energy (optical-to-optical
efficiency of 20%);
-
The buried
cladding depressed waveguides with radius of
120 µm emitted laser
pulses at 1.32 µm with energy of 0.4 mJ;
-
Laser emission
at 946 nm was observed from the same waveguide.
Note: To the
best of our knowledge this is the first report on laser emission at
1.32 µm from
Nd:YAG waveguides realized by direct fs-laser writing technique, while
the
laser performances at both 1.06 and 1.32 µm
wavelengths are the highest obtained
under the pump with diode lasers. Further works will consider
improvement of the
writing technique, especially for the buried depressed cladding
waveguides, and realizing of laser emission with increased performances.
●
Research
on realizing Nd:YAG ceramics media by the solid-state sintering method
have been conducted.
●
Raportul
stiintific pe anul 2012 este disponibil aici: | 2012
|
___________________________________________________________________________________________________________________________________________________________________________
3.
STAGE
III. December 2013
Value:
229.808,84 lei
OBJECTIVES
1.
Waveguides inscribed by fs-laser writing technique in Nd-vanadate laser
crystals.
2. Waveguide lasers in Nd-vanadates under pumping with diode lasers.
3. Writing of waveguides in Nd:YAG ceramic
media.
4. Transparent laser medium realized by ceramics
techniques (first stage).
RESULTS
●
Experiments
on writing waveguides in Nd-vanadate laser crystals (Nd:YVO4
si
NdGdVO4) have been
performed; changes of the refraction index were realized in Nd:YVO4
up to a depth of 400 µm
and in NdGdVO4 up to
200 µm depth. The minimal fluence of the
fs-laser beam that realized changes at the laser crystals surface
was 2.0
J/cm2, and this value increased to
3.4-4.0 J/cm2
for depths between 200 and 400 µm. Experiments on laser emission
under diode-laser pumping are in progress.
● Two-wall
type and buried, buried cladding depressed waveguides (of cylindrical
shape)
were realized in Nd:YAG ceramics.
● Circular,
buried depressed-cladding waveguides were realized in a 5.0-mm long,
1.1-at.% Nd:YAG
ceramic by direct femtosecond-laser writing using a scheme in which the
laser
medium is moved on a helical trajectory along its axis and parallel to
the
writing direction.
●
Raportul
stiintific pe anul 2013 este disponibil aici: | 2013
|
___________________________________________________________________________________________________________________________________________________________________________
4.
STAGE
IV. December 2014
Value:
190.000 lei
OBJECTIVES
1.
Transparent laser medium realized by ceramics techniques (continuation).
2. Laser emission from waveguides inscribed in Nd:YAG ceramic media.
3. Waveguides
lasers realized by direct fs-laser writing in Nd:YVO4
and Nd:GdVO4.
RESULTS
● Employing the
pump with a fiber-coupled
diode laser, laser
emission at 1.06 μm and 1.3 μm was
achieved in buried waveguides that were inscribed
in Nd:YAG ceramic media by fs-laser writing method. A circular cladding
waveguide of 100-μm diameter inscribed in a 0.7-at.%
Nd:YAG delivered laser pulses at 1.06 μm with 2.8-mJ energy and 0.49-W
cw power
with overall optical-to-optical efficiency of 0.21 and 0.13,
respectively.
Laser pulses at 1.3 μm with 1.2-mJ energy were obtained from a 50-μm in
diameter circular waveguide.
● Circular
cladding waveguides were inscribed by helical movement of the laser
medium
during the direct fs-laser writing process. Laser pulses with 3.4-mJ
energy at
1.06 μm and with 1.2-mJ energy at 1.3 μm under the pump with pulses of
13.1-mJ
energy at 807 nm were obtained from a 100-μm diameter circular
waveguide that
was inscribed in a 1.1-at % Nd:YAG ceramic. The same waveguide yielded
0.48-W
cw output power at 1.06 μm. Pulses at 1.06 μm with energy up to 4.1 mJ
(overall
optical-to-optical efficiency of 0.31) were obtained from a 50-μm
diameter
circular waveguide. For comparison, a circular waveguide with 100-μm
diameter
was inscribed by the classical translation method in the same medium.
This
device outputted laser pulses with maximum energy of 2.2 mJ at 1.06 μm
and of
0.82 mJ at 1.3 μm. Optimization of the new inscribing procedure is
necessary
and should include the choice and correlation of the focusing optics,
of the fs-laser
pulse energy and of the helical trajectory parameters. These results
show that
the helical movement of the laser medium during fs-laser writing could
be a
step forward towards realization of efficient integrated lasers
consisting of
cladding waveguides pumped by diode lasers.
● Efficient
1.06 μm and 1.34 μm
laser emission from cladding waveguides inscribed by femtosecond-laser
writing
technique in Nd:YVO4 has been obtained using
diode laser pumping. Employing the
classical pump
at 808 nm (i.e. into the highly-absorbing 4F5/2
level), laser
pulses at 1.06 μm with 3.0-mJ
energy at optical efficiency of 0.30 and
0.32 slope efficiency have been measured from a circular waveguide of
100-μm
diameter that was inscribed in a 0.7-at.% Nd:YVO4
crystal. It has
been proved that the pump directly into the 4F3/2
emitting
level is an effective method for improving the emission performances of
such a
laser device. Under the pump at 880 nm the same waveguide yielded laser
pulses with increased energy of 3.8 mJ, at higher optical efficiency
and slope
efficiency of 0.36 and 0.39, respectively. Cw output power of 1.5 W at
1.06 μm was outputted
by this waveguide for the pump at 880 nm, in comparison with the 0.9-W
output
power that was achieved for the 808-nm pump. A similar waveguide
inscribed in a
0.5-at.% Nd:YVO4 crystal yielded laser pulses at
1.34 μm with
1.5-mJ energy (at 0.14 optical efficiency) and slope efficiency of
0.19,
whereas the pump at 880 nm improved the pulse energy at 1.8 mJ (with
optical
efficiency of 0.18) and increased the slope to 0.23. The results of
this work suggest that the pump with diode lasers directly into the
emitting
level could be a good solution for realization of efficient waveguide
lasers that
are inscribed in Nd-vanadate laser media.
●
Raportul
stiintific pe anul 2014 este disponibil aici:
| 2014
|
___________________________________________________________________________________________________________________________________________________________________________
___________________________________________________________________________________________________________________________________________________________________________
●
Short resume of the results (2011-2014), in English:
| here|
___________________________________________________________________________________________________________________________________________________________________________
___________________________________________________________________________________________________________________________________________________________________________
5.
STAGE V. December 2015
Value:
151.386 lei
(according to Act Aditional nr. 3/2015)
OBJECTIVES
1.
Transparent laser medium realized by ceramics techniques (continuation).
2.
Hibrid waveguide lasers: Passively
Q-switched Nd:YAG/Cr4+:YAG
lasers.
RESULTS
● Efficient
continuous-wave laser emission was obtained using the pump with
fiber-coupled
diode laser of circular (100-μm
diameter), buried depressed cladding waveguides
that were inscribed in several Nd:YAG ceramics by fs-laser beam writing
method.
Output powers of 3.1 W at 1.06 μm and of
1.6 W at 1.3 μm were
measured from a 4.5-mm long waveguide that was inscribed in a 1.1-at.%
Nd:YAG
using a novel, helical-moving of the medium writing technique. The
optical-to-optical efficiency was 0.32 at 1.06 μm and 0.17
at 1.3 μm,
whereas the slope efficiency was 0.43 and 0.19, respectively.
● Laser
operation in Q-switch regime was obtained with Cr4+:YAG
SA, the waveguide
laser delivering 680 mW average power, in pulses with 19.7-μJ
energy at 7-kW pulse peak power.
● Circular
buried depressed-cladding waveguides with were inscribed in composite
Nd:YAG/Cr4+:YAG
single crystals.
●
Raportul
stiintific pe anul 2015 este disponibil aici:
| 2015
|
___________________________________________________________________________________________________________________________________________________________________________
6.
STAGE VI. December 2016
Value:
317.805,16 lei
(according to Act Aditional nr. 3/2015)
OBJECTIVES
1.
Transparent laser medium realized by ceramics techniques (final stage).
2.
Hibrid waveguide lasers: Passively
Q-switched Nd-vanadates - Cr4+:YAG
lasers.
3.
Waveguide laser for generation of green light at
0.53 µm.
RESULTS
● Efficient
laser emission was obtained using the pump with fiber-coupled diode
laser of
circular (100-μm diameter),
buried depressed-cladding waveguides
that were inscribed in Nd:YAG ceramics by fs-laser beam writing method.
Output
powers of 3.1 W at 1.06 mm and of 1.6 W
at 1.3 μm were
measured from a 4.5-mm long waveguide that was inscribed in a 1.1-at.%
Nd:YAG
using a novel, helical moving of the medium, writing technique. The
optical-to-optical efficiency was 0.32 at 1.06 μm and 0.17 at
1.3 μm,
whereas the slope efficiency was 0.43 and 0.19, respectively. Laser
operation
in Q-switch regime was obtained with Cr4+:YAG
SA, the waveguide
laser delivering 680 mW average power, pulses with 19.7-μJ
energy at 7-kW pulse peak power. The data reported for both cw and
Q-switch
operation are the highest for such configurations.
● Buried
depressed-cladding waveguides with 100-μm diameter have
been realized
in several Nd:YVO4 laser crystals by fs-laser
writing technique. The
performances of cw laser emission at 1.06 μm and
1.34 μm were
measured under the pump at 808 nm (into the highly-absorbing 4F5/2
level) as well as at 880 nm (directly into the 4F3/2
emitting level) with fiber-coupled diode lasers. The best results were
recorded
from an waveguide that was inscribed in a 6.9-mm long, 0.5-at.% Nd:YVO4
crystal. Thus, output power of 4.4 W at 1.06 μm was obtained
for an absorbed
pump power of 9.8 W at 880 nm, corresponding to an overall
optical-to-optical
efficiency (with respect to the absorbed pump power) of 0.45. The slope
efficiency was 0.47. For the emission at 1.34 mm
the output power reached 1.7
W with optical-to-optical efficiency of 0.17; the slope efficiency
amounted to
0.24. Comparative results are given and discussed for the pump at 808
nm of all
the Nd:YVO4 media employed in the experiments.
●● The
data reported in these works are the highest output powers obtained to
date
from waveguides inscribed in Nd:YAG and Nd:YVO4
and show the
potential of the waveguides inscribed by fs-laser beam technique to
realize efficient
integrated laser sources pumped by
fiber-coupled diode lasers.
● Transparent
Nd:YAG ceramics (0.5-at.% Nd, 1.0-at.% Nd and 1.5-at.% Nd) were
obtained by
solid-state reaction method.
●
Raportul
stiintific sintetic este disponibil aici:
| 2016
|
___________________________________________________________________________________________________________________________________________________________________________
PUBLICATIONS
ARTICLES
PUBLISHED IN ISI JOURNALS
10. G. Croitoru (Salamu), F. Jipa, and
9.
G. Salamu and N.
Pavel, “Power scaling from buried
depressed-cladding waveguides realized in Nd:YVO4
by
femtosecond-laser beam writing," Opt. & Laser Techn. 84,
149-154
(2016). (doi:10.1016/j.optlastec.2016.05.015) [2016 Impact
Factor: 2.109]
8.
G. Salamu, F.
Jipa, M. Zamfirescu, and N. Pavel,
“Watt-Level Output Power Operation from Diode-Laser Pumped Circular
Buried
Depressed-Cladding Waveguides Inscribed in Nd:YAG by Direct
Femtosecond-Laser
Writing,” IEEE Photonics Journal 8(1),
art. 1500209 (2016). (DOI: 10.1109/JPHOT.2015.2512263; http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=4563994) [2016 Impact
Factor: 2.291]
7. N.
Pavel, G. Salamu, F. Jipa, and M. Zamfirescu, “Diode-laser pumping
into the emitting level for efficient lasing of depressed cladding
waveguides
realized in Nd:YVO4 by the direct
femtosecond-laser writing
technique,” Opt. Express 22
(19), 23057-23065 (2014). (http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-22-19-23057) [2014 Impact
Factor: 3.488]
6.
N. Pavel, G.
Salamu, F. Voicu, F. Jipa, and M.
Zamfirescu, “Cladding waveguides realized in Nd:YAG laser media by
direct
writing with a femtosecond-laser beam,” Proceedings of the
5.
G. Salamu, F.
Jipa, M. Zamfirescu, and
Note: This paper was included by OSA in the list of “Optical
Materials Express’ 15 Most
Cited Articles”.
4. G. Salamu, F.
Jipa, M. Zamfirescu, and
3.
G. Salamu, F. Voicu,
Rom.
Reports in Physics 64
(3), 943-953 (2013) (http://www.rrp.infim.ro/2013_65_3/A29.pdf). [2013 Impact
Factor: 1.137]
2.
N. Pavel, G. Salamu, F. Voicu, F. Jipa, M. Zamfirescu, and T. Dascalu,
“Efficient laser emission in diode-pumped Nd:YAG buried waveguides
realized by
direct femtosecond-laser writing,” Laser Physics Letters 10
(9), 095802 (2013) (http://iopscience.iop.org/1612-202X/10/9/095802).
[2013 Impact Factor: 2.964]
1. T.
Dascalu, G. Salamu, O. Sandu, F. Voicu, and
Note:
This work was partially (30%) supported from this project.
PATENTS
● T. Dascalu, N.
Pavel,
G. Salamu, O. Grigore, F. Voicu, M. Dinca, "Sistem
laser monolitic, compozit si compact cu livrare
simultana a doua fascicule laser /
Compact, composite, monolithic laser system with simultaneous emission
of two
laser beams," Romanian patent, OSIM application number A-100417 /
03.05.2013.
Note:
The patent was
partially (20%) supported from this project.
PROCEEDINGS
2. G. Salamu, F.
Voicu, F. Jipa, M. Zamfirescu, T.
Dascalu, and
1. G.
Salamu, A. Ionescu, C. Brandus, O. Grigore, N. Pavel and T. Dascalu,
"Generation of high-peak power 532-nm green pulses from composite,
all-ceramics, passively Q-switched Nd:YAG/Cr4+:YAG
laser," Proc.
SPIE 8882, ROMOPTO 2012: Tenth Conference on
Optics: Micro- to
Nanophotonics III, 888206 (June 10, 2013); doi:10.1117/12.2032267 (http://dx.doi.org/10.1117/12.2032267).
Note: This work
was partially (50%) founded from this project.
CONFERENCES
17. G.
Croitoru, T. Dascalu, F. Jipa, M. Zamfirescu, N. Pavel, “High-power operation in
circular buried depressed-cladding waveguides inscribed in Nd:YAG and
Nd:YVO4
by femtosecond-laser beam,” 7th EPS-QEOD EUROPHOTON CONFERENCE, Solid
State, Fibre, and Waveguide
Coherent Light Sources, 21-26
August, 2016, Vienna,
Austria, presentation FWG-4.4 (oral
presentation).
16. G. Salamu, N.
Pavel, T. Dascalu, F. Jipa,
M. Zamfirescu, “Power-scaling
from burried depressed-cladding waveguides
realized in Nd:YAG and Nd:YVO4 by direct writing
with a femtosecond-laser
beam,” The 16th
International Balkan Workshop on
Applied Physics, 7-9 July, 2016, Constanta, Romania;
Book of Abstracts, pp.
77-78 (S2 L3, invited presentation).
15.
N. Pavel, G.
Salamu, F. Voicu, O. Grigore, T.
Dascalu, F. Jipa, and M. Zamfirescu,
“Depressed-cladding
waveguides inscribed in Nd:YAG and Nd:YVO4 by
femtosecond-laser
writing technique. Realization and laser emission,” ROMOPTO
2015, 11th International Conference on Optics
“Micro- to
Nano-Photonics IV”, September 1-4, 2015, Bucharest, Romania;
presentation I.I.7
(invited presentation).
14. G. Salamu, F.
Voicu, F.
Jipa, M. Zamfirescu, T. Dascalu, N. Pavel, ”Efficient Laser Emission
from
Waveguides Inscribed in Nd-doped Media by Femtosecond-Laser Writing
Technique,”
“Siegman International School on Lasers: 2015”, 02-07 August 2015,
Amberg,
Germania (poster presentation).
13.
G. Salamu, N.
Pavel, T.
Dascalu, F. Jipa, and M. Zamfirescu, “Diode-Pumped
Laser Emission from Depressed Cladding Waveguides Inscribed in Nd-doped
Media
by Femtosecond Laser Writing Technique,”
CLEO Europe - EQEC 2015 Conference, 21-25 June 2015, Münich, Germany,
presentation CA-P.29 (poster presentation).
12.
N.
Pavel, G. Salamu, F. Jipa, and M. Zamfirescu, “Efficient Laser Emission under 880-nm
Diode-Laser Pumping of Cladding Waveguides Inscribed in Nd:YVO4
by
Femtosecond-Laser Writing Technique,“ Advanced
Solid State Lasers (ASSL) Congress, 16-21 November 2014, Shanghai,
China,
presentation ATu2A.26 (poster
presentation).
11. G.
Salamu, F. Jipa, M. Zamfirescu, F. Voicu, and N. Pavel, “Laser emission
from diode-pumped Nd:YAG waveguide lasers realized by
femtosecond-writing technique,”
5th International Student Conference on Photonics,
10. N. Pavel, G.
Salamu, F. Jipa, M. Zamfirescu, F. Voicu, and T. Dascalu,
”Efficient
laser emission in
diode-pumped Nd:YAG cladding waveguides fabricated by direct writing
with a
helical movement technique,” 6th
EPS-QEOD
EUROPHOTON
CONFERENCE, Solid
State, Fibre, and Waveguide Coherent Light Sources,
24-29
August, 2014, Neuchâtel, Switzerland, presentation TuP-T2-P-02
(poster presentation);
Europhysics Conference Abstract Vol. 38 E; ISBN 2-914771-89-4.
9. N. Pavel, G.
Salamu, F. Voicu, T. Dascalu, F. Jipa,
and M. Zamfirescu, “Waveguides Fabricated in Nd:YAG by Direct fs-Laser
Writing -
Realization and Laser Emission under Diode-Laser Pumping,” The 14th
International Balkan Workshop on Applied Physics, July 2-4, 2014,
Constanta,
Romania, presentation S2-L07, Book of Abstracts p. 106 (invited
presentation).
8. G. Salamu, F.
Jipa, M.
Zamfirescu, and N. Pavel, “Laser Emission from Nd:YAG Laser Waveguides
Realized
by Femtosecond-Laser Writing Techniques,” 2014 Photonics Europe SPIE
Conference,
14-17 April 2014,
7.
N. Pavel, G. Salamu, F. Jipa, and M. Zamfirescu, “Laser emission
from diode-pumped Nd:YAG waveguides,
realized by direct femtosecond-laser writing technique,“
Advanced
Solid State Lasers (ASSL) Congress, 27 October - 1 November 2013,
Paris,
France, presentation ATu2A.6 (oral presentation).
6. N.
Pavel, G. Salamu, F.
Voicu, F. Jipa, and M. Zamfirescu, “Femtosecond-laser inscribed Nd:YAG
waveguides. Realization and laser emission,“ LPHYS’13:
22nd International Laser Physics Workshop, Prague, 15-19 July, 2013,
presentation 4.1.3 (oral presentation).
5. G. Salamu, F.
Voicu, N. Pavel, T. Dascalu, F. Jipa,
and M. Zamfirescu, “Diode-pumped laser emission in femtosecond-laser
inscribed
Nd:YAG waveguides,” International Conference "Modern
Laser Applications" Third Edition, INDLAS
2013, 20-24 May 2013, Bran, Romania, presentation O1 (oral
presentation).
4.
G. Salamu, F. Voicu, F. Jipa, M. Zamfirescu, N.
Pavel, “Direct femtosecond laser
written waveguides in Nd:YAG,” Micro- to Nano-Photonics
III, ROMOPTO
2012, 10th International Conference on Optics,
3-6 September, Bucharest, Romania, presentation II.P. 1 (poster
presentation)
Note: This work was awarded with the Certificate of
Excellence for First
Place Student Presentation and Best Poster SPIE Award at the ROMOPTO
2012
conference.
1. N. Pavel and
T. Dascalu, ”High-peak power
passively Q-switched Nd:YAG/Cr4+:YAG lasers,”
International Student
Conference on Photonics 2012, SPIE Student Chapter, 8-11 May 2012,
Sinaia,
Romania. Book
of
abstracts, ISSN 2284-9750, p. 79 (invited presentation).
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