E.D. D’silva et al. / Physica B 406 (2011) 2206–2210
2209
load as shown in Fig. 6. Similar behavior was observed for the
crystals p-chloro dibenzylideneacetone [8], lanthanum doped potas-
sium pentaborate (KB5) [9], pure and KOH doped glycine phosphate
efficiency of any nonlinear optical material taken in its powder
form [14]. The crystal was ground into uniform powder and then
packed in a microcapillary of uniform bore and exposed to a
Q-switched Nd:YAG laser beam of wavelength 1064 nm. The laser
beam was made to fall normally on the sample capillary tube and
the output from the sample was monochromated to collect the
intensity of 532 nm component. The generation of second harmonic
was confirmed by the emission of green light. The beam energy of
the Nd:YAG laser operating at 1064 nm is set to 3.2 mJ/pulse. The
second harmonic generation efficiency for 3Br4MSP is found to be
2.92 times that of urea (where urea was grounded to uniform
particle size as the experimental sample 3Br4MSP and was used as
reference material for the present measurement).
[10], L-Alanine Cadmium Chloride [11]. We compared the Vickers
hardness value of 3Br4MSP at the applied load of 10 g with the NLO
materials reported in literature. It was found that the 3Br4MSP
has better hardness value (25 kg/mm2) compared to that of
DMMC (11.88 kg/mm2) [3], urea (6.5–11 kg/mm2) and N-methyl
urea (12–19 kg/mm2) [12].
3.4. UV–Vis–NIR spectral studies
The UV–Vis–NIR absorption spectrum of the crystal was
recorded using a Cary 5E high resolution spectrophotometer in
the wavelength range of 200 to 1100 nm as shown in Fig. 7 [13].
The cutoff wavelength for this crystal is found to be 398 nm. The
3
.6. Laser damage studies
*
maximum absorption is to be assigned for the transition of p–p
and n-
The utility of NLO crystal depends not only on the linear and
*
p due to the excitation in aromatic ring and C¼O group.
NLO properties but also largely on its ability to withstand high
power lasers [15]. The laser damage threshold (LDT) studies were
carried out on single crystals using a Q-switched Nd:YAG laser
source of pulse width 6 ns at a wavelength of 1064 nm and a
The wide transparency range extending from visible to IR region
may be helpful for these crystals to be used for NLO applications.
3.5. SHG efficiency
1
0 Hz repetition rate operating in TEM00. The crystal 3Br4MSP
2
The method developed by Kurtz and Perry is the easiest
setup to evaluate second harmonic generation (SHG) conversion
has laser damage threshold of 0.478 GW/cm . This LDT value is
comparable with the known high quality crystals like KDP, Urea,
BBO, etc.
2
1
1
00
50
00
4
. Conclusion
The new nonlinear optical chalcone derivative 3Br4MSP was
synthesized and the crystals were grown by slow evaporation
technique. Single crystal X-ray diffraction study of the crystal
reveals that the crystal belongs to orthorhombic system with
space group Pbca. 3BrMSP crystals were stable up to 92.87 1C.
Vickers and Knoop hardness number were found to decrease with
increase in the applied load. Crystals have good transparency
range beyond the cutoff (398 nm), extending into IR region. The
SHG efficiency of this crystal is 2.93 times that of urea. The single
shot laser damage threshold for 3Br4MSP crystal is comparable
with that of high quality crystals and the value is found to be
HV
5
0
0
HK
2
2
3
4
5
6
7
8
9
10
11
0.478 GW/cm . Due to the presence of wide transparency range,
good damage threshold value and SHG efficiency, this crystal may
be used for NLO applications.
Load (g)
Fig. 6. Plot of hardness number vs. load.
0
0
0
0
0
.4
.3
.2
.1
.0
Acknowledgment
Authors acknowledge the Department of Science and Technol-
ogy (DST), Government of India for financial assistance and are
grateful to SAIF Cochin and SAIF Madras for providing experi-
mental facilities.
References
[
[
1] J. Badan, R. Hierle, A. Perigand, J. Zyss, in: D.J. Williams (Ed.), Nonlinear
Optical Properties of Organic Molecules and Polymeric Materials, American
Chemical Society, Washington, DC, 1993.
2] V. Crasta, V. Ravindrachary, R.F. Bhajantri, R. Gonsalves, Journal of Crystal
Growth 267 (2004) 129.
[3] V. Shettigar, P.S. Patil, S. Naveen, S.M. Dharmaprakash, M.A. Sridhar, J. Shashidhara
Prasad, Journal of Crystal Growth 245 (2006) 44.
[
[
4] P.S. Patil, S.M. Dharmaprakash, Journal of Crystal Growth 305 (2007) 218.
5] P.S. Patil, S.M. Dharmaprakash, Hoong-Kun Fun, M.S. Karthikeyan, Journal of
Crystal Growth 297 (2006) 111.
4
00
600
800
1000
[
[
6] P.S. Patil, S.M. Dharmaprakash, K. Ramakrishna, Hoong-Kun Fun, R. Sai
Santosh Kumar, D. Narayana Rao, Journal of Crystal Growth 303 (2007) 520.
7] Hou Wenbeo, Yuan Duorong, Xu Dong, Jiang Minhua, Journal of Crystal
Growth 133 (1993) 71.
wavelength (nm)
Fig. 7. UV–Vis–IR spectrum of the crystal.