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Second harmonic generation in the Gd2(MoO4)3 crystal grown by the Czochralski method
December
ELSEVIER
1995
Materials Letters 25 (1995)
195-198
Second harmonic generation in the Gd,( Moo,) 3 crystal grown by the Czochralski method Sun 11Kim a**, Junghwan Kim b, Sung Chul Kim b, S.I. Yun ‘, T.Y. Kwon ’ aDepartment of Natural Sciences, Pusan National University of Technology, Pusan 608-739, South Korea b Department of Physics, Dongeui University, Pusan 614-714, South Korea ’ Department of Physics and Research Centerfor Dielectric and Advanced Matter Physics, Pusan National University?Pusan 608-735, South Korea Received 1 February 1995; revised 19 July 1995; accepted 24 July 1995
Abstract The characteristics of the second harmonic generation (SHG) in the Gdz( MoOq)g crystal grown by the Czochralski method were investigated at 1.064 pm light from an Nd : YAG laser. The phase matching angle, angular acceptance bandwidth and the temperature bandwidth were measured in type I phase matching. The nonlinear coefficient and SHG conversion efficiency were also obtained.
The Gd2( MOO,) 3 (GMO) crystal belongs to orthorhombic space group (point group mm2) and is a positive biaxial crystal [ 1,2]. The crystallophysical axes x, y, z of the GM0 crystal are parallel to the crystallographic axes b, a and c, respectively. It exhibits both ferroelectricity and ferroelasticity, and has potential applications in the electrooptical devices [3] and acoustic wave devices [ 41. Above the Curie temperature (T, = 159°C)) the unit cell becomes tetragonal with space group P42,m. ‘Many nonlinear optical crystals, such as NI-&H,PO, (ADP), KH,P04 (KDP), KTiOPO, (KTP), LiIO,, LiNbO,, LiB,O, (LBO), j?-BaB,O, (BBO) [ 51 have been studied extensively since the first generation of doubled frequency light by Franken et al. [ 61. KTP, LiIO,, LB0 and BBO have good second harmonic generation (SHG) characteristics, however, it is difficult to grow them and the LiIO, is hygroscopic [ 71. Among various nonlinear optical crystals, the GM0 crystal is * Corresponding
author.
0167-577x/95/$09.50 0 1995 Elsevier Science B.V. All rights reserved SSDIO167-577x(95)00180-8
relatively easy to grow. However, little attention has been paid to the GM0 crystal as a nonlinear optical crystal. There are a few reports on SHG of the GM0 crystal. Miller et al. [ 81 measured the nonlinear optical coefficients of the GM0 crystal using the Maker fringe method. Bonneville et al. [ 91 measured the linear and nonlinear optical coefficients to investigate the influence of the lanthanide ions on the nonlinear optical properties of the GM0 crystal. Borchardt et al. [lo] were the first researchers who introduced the GM0 crystal as the ferroelectric laser host and demonstrated the laser operation of the GM0 crystal. Bagdasarov et al. [ 111 proposed the possibility of a self-doubling laser with the GM0 crystal. In this Letter, we report the characteristics of critically phase-matched SHG of 1.064 pm light in the GM0 crystal grown by the Czochralski method. Angle tuning and temperature tuning curves of SHG at a fundamental wavelength of 1064 nm from a pulsed Nd : YAG laser were obtained in type I phase matching. The SHG conversion efficiency and effective non-
XI. Kim et al. /Materials
196
Fig. 1. Experimental
geometry
for the type I SHG.
linear coefficient of the GM0 crystal at a pulsed 1064 nm light were also measured and compared with wellknown nonlinear optical crystals. For the preparation of the GM0 crystal, Gd203 (99.9%, Aldrich, USA), MOO, (99.9%, Soegawa, Japan) and Pr601, (99.9%, Aldrich, USA) were mixed and ball-milled for 24 h and dried at 150°C for 24 h. They were calcined for 10 days at 780°C. The GM0 crystals were grown from this compound by the Czochralski method. The rotational speed of the seed was 48 rpm, and the pulling speed was 2.8 mm/h [ 121. The preferential growing direction was (110). A clear GM0 single crystal with a length of 50 mm and a diameter of 13 mm was obtained by this method. The prepared GM0 crystal was nonhygroscopic and transparent from 0.31 to 5.13 p,m. The fundamental beam for the SHG in the GM0 crystal was the 1.064 pm light from a pulsed Nd : YAG laser (SL804G, Spectron) with a pulse width of 6 ns. After generating doubled light through the GM0 crystal, the 532 run SHG light was separated from the fundamental light by a dispersive prism. A monochromator (1702, SPEX) and a PM tube (C3 1034, RCA) were employed to detect 532 nm light from the GM0 crystal. The detected signal was read out by a digital oscilloscope (9450A, LeCroy ) . In order to measure the SHG conversion efficiency of the GM0 crystal, a calorimeter (38-0101, Scientech) and a microvoltmeter ( 197, Keithley) were used. The transmission curve of the GM0 crystal was obtained using a spectrophotometer (Cary 5, Varian) and an FT-IR spectrophotometer (5020/5060, Galaxy ) . The transparent range of the GM0 crystal is 0.3 1 to 5.13 pm. The UV transparency of this crystal is comparable to KTP ( KTiOPO,, 0.35 pm) and is even better than that of LB0 (LiB,O,, 2.6 pm) in IR [ 51. Fig. 1 illustrates the experimental geometry for the type I SHG. The z-axis of the GM0 crystal is in the cut plane of the crystal and the x-axis is rotated about the z-axis by 43.5” from the cut plane. In order to measure
Letters 25 (1995) 195-198
the angular and temperature dependence, the GM0 crystal was mounted on a goniometer. The fundamental beam was directed at 8 and 4 to the z- and x-axes, respectively. The fundamental beam was polarized along the z-axis and the SHG light was polarized perpendicular to z-axis. Biaxial crystals such as KTP, LBO, GM0 have non-isotropic physical properties along the angle 4, therefore the phase matching angle for the angle 8 is different along the angle 4. Hobden [ 131 has shown that there are 13 topologically different patterns of phase matching loci in the condition of normal dispersion of biaxial crystals. The refractive indices of the GM0 crystal were measured by Bonneville et al. [ 91 1.8148,n1,= 1.861Oat l.O64pm, asnIx = 1.8144,n,,= and n2,= 1.8547, nZy= 1.8551, nzz= 1.914 at 532 nm. These data suggest that the type I phase matching (eeo interaction) is possible at 1.064 u,rn in the GM0 crystal. Therefore the eighth of Hobden’s patterns was observed in the situation where nzz > n,, > n2,,> n2, > nly>nlx, n,> (nl,+nl,)/Z nzy> (nl,+nJ/2. Fig. 2 shows the SHG intensity of the GM0 crystal as a function of external angle 8. The peak of the SHG intensity was achieved at 0,,, = 46.6”, &ext= 43.5”. The corresponding internal phase matching angle 8is 68.3”. This value is in good agreement with the angle 69.0” calculated from the refractive indices of the GM0 crystal [ 93. The SHG power is proportional to the function sin2(Ak1/2)l(AkZ/2)* [ 131, as the GM0 crystal of length 1 is deviated from the phase matchig angle. The phase mismatch Ak is given by
la2-
42
44
46
48
50
52
Q.,(ded Fig. 2. Second harmonic of external angle &,.
intensity of the GM0 crystal as a function
XI. Kim et al. /Materials Letters 25 (1995) 195-198
Fig. 3. Second harmonic of external angle A,,.
intensity of the GM0 crystal as a function
1.2 (I) 2 d 1.0 9 e 0.6 cd h 2
0.6
2 0, 0.4 2 E
0.2 0.0 20
40
60
60
100
120
For the exact phase matching, A k( $, To, qJ = 0 has to be satisfied. The angular acceptance can be obtained by finding the angle difference from the phase matching peak to the first zero. This angle difference is approximately equal to the full width at half-maximum (fwhm) of the the peak. Experimental data were fitted to the function, sin*( AkZ/2) / (Ak1/2)*, to measure the angular acceptance bandwidth. Angular acceptance bandwidth for the internal angle 19was obtained as A Ol= 1.2 mrad cm from fwhm by fitting. The angular acceptance bandwidth predicted from the indices of the GM0 crystal is A @= 1.5 mrad cm, and this is in good agreement with the experimental result. Fig. 3 shows the SHG intensity of the GM0 crystal as function of 8 around phase matching angle &, = 43.5” at &,, = 46.6”. Experimental data were fitted to the function, sin*( A kll2) I (Ak1/2)‘, to give the angular acceptance bandwidth of A +Z = 37.6 mrad cm for internal angle 4. Fig. 4 shows the SHG intensity of the GM0 crystal as a function of temperature T at external angle 8= 67.9”. The temperature acceptance bandwidth was measured as A Tl = 5.6”C cm. In general, A TZ is larger in the nonuniform material than in the uniform one [ 141. Therefore, this value can be used as a measure of the optical quality of the materials. In Table 1, the characteristics of the SHG in the GM0 crystal are summarized for comparison with those of some other nonlinear optical crystals.
Temperature(%) Fig. 4. Second harmonic of temperature.
197
intensity of the GM0 crystal as a function 2.5
0
Fundamental 50 I
d.,,=1.2f0.2
Ak=k,(~)
+k*(~)
-k3(20),
Power(mW) 100 I
pm/V
-
(1)
+WW 6T+ 8T
en,Tn, w,
a(Ak) &a a&J
a(Ak)
0.6
g
x
B
where k,(w) and k2( o) are the wave vectors of the fundamental wave, and k,(2w) is the wave vector of the second harmonic. The phase mismatch A k is a function of the sample temperature T, frequencies of the interacting waves and the angles. The dependence of A k on these parameters is given by
A& 0, T, w>= Ak(
150 1.0
- 0.6 .x 2 -0.4
;=; c
j+ae ..
s.
Fundamental
(2)
Intensity(MW/cm2)
Fig. 5. Second harmonic intensity of the GM0 crystal as a function of fundamental intensity.
XI. Kim et al. /Materials Letters 25 (1995) 195-198
198
Table 1 Comparison Crystal
KDP KTP BBO LB0 LiNbO, LiIO, GM0
of the characteristics Transparency
of SHG in the GM0 crystal and some other nonlinear crystals
(pm)
Temperature (“C cm)
0.2-1.5 0.3.5-4s 0.19-3.0 0.16-2.6 0.4-5 0.3-5.5 0.31-5.13
3.4 25 55 9 0.6 6.9 5.6
“Angular acceptance
bandwidth
range
for non-critical
phase-matching
Angular acceptance (mrad cm)
bandwidth
0.84 1.5 1.5 9 41” 0.32 3.4 (mrad cm”*).
Fig. 5 shows the SHG power and the conversion efficiency of the GM0 crystal as a function of fundamental intensity. The filled circle points in Fig. 5 were fitted to the conversion efficiency equation [ 151, 77= tanh’( Cdetiln3f21”21),
bandwidth
(3)
where I is the peak intensity of the fundamental beam, C= 27x( &eo) 1’4/h and h is the wavelength of the fundamental beam. The effective nonlinear coefficient of the GM0 crystal de,= 1.2 f 0.2 pm/V was obtained from this fitting. This value is about four times larger than the d36 of KDP, and five times smaller than the d,5 of KTP [ 51. The SHG conversion efficiency of a 1.4 mm thick GM0 crystal was about 0.76% at a fundamental intensity of 126 MW/cm2. In summary, we have grown the GM0 crystal by the Czochralski method and investigated the characteristics of type I SHG in the GM0 crystal at 1.064 pm. The phase matching angle was measured and coincided well with the calculated value. The angular acceptance bandwidths A 81, A 41 and the temperature bandwidth A TZwere obtained as 1.2 mrad cm, 37.6 mrad cm and 5.6”C cm, respectively. The effective nonlinear coefficient and SHG conversion efficiency of the GM0 crystal were de, = 1.2 + 0.2 pm/V and 0.76% at a fundamental intensity of 126 MW/cm2, respectively. Acknowledgements The present studies were supported by the Korean Science & Engineering Foundation (KOSEF) through
the Research Center for Dielectric and Advanced Matter Physics (RCDAMP) at Pusan National University.
References
[ 1 ] K. Nassau, H.J. Levinstein and G.M. Loiacono, J. Phys. Chem. Solids 26 (1965) 1805. [2] K. Aim, J. Phys. Japan 26 (1969) 387. [3] A. Kumada, Ferroelectrics 3 (1972) 115. [4] L.A. Coldren, R.A. Lemons, A.M. Glass and W.A. Banner, Appl. Phys. Letters 30 ( 1977) 506.
[ 51 V.G. Dmitriev, G.G. Gurzadyan
[ 61 [ 71 [8] [9]
and D.N. Nikosyan, eds., Handbook of nonlinear optical crystals (Springer, New York, 1991). P.A. Franken, A.E. Hill, C.W. Peters and G. Weinreich, Phys. Rev. Letters 7 (1961) 118. G. Nath and S. Haussuhl, Appl. Phys. Letters 14 ( 1969) 154. R.C. Miller, W.A. Nordland and K. Nassau, Ferroelectrics 2 (1971) 97. R. Bonneville and F. Auzel, J. Chem. Phys. 67 ( 1977) 4597.
[ 101 H.J. Borchardt andP.E. Bierstedt, Appl. Phys. Letters 8 ( 1966) 50.
[ 111 Kh. S. Bagdasarov,
G.A. Bogomolova, A.A. Kaminskii, A.M. Prokhorov and T.M. Prokhortseva, Soviet Phys-Doklady 16 (1971) 216. [ 121 S.C. Kim, J.D. Park, J.H. Kim, Y.S. Lyu and Y.J. Kim, Dongeui-non-jip 13 (1986) 53. [ 131 M.V. Hobden, J. Appl. Phys. 38 (1967) 4365. [ 141 R.A. Stolzenberger, Appl. Opt. 27 (1988) 3883. [ 151 Y.R. Shen, The principles of nonlinear optics (Wiley, York, 1984).
New
ELSEVIER
1995
Materials Letters 25 (1995)
195-198
Second harmonic generation in the Gd,( Moo,) 3 crystal grown by the Czochralski method Sun 11Kim a**, Junghwan Kim b, Sung Chul Kim b, S.I. Yun ‘, T.Y. Kwon ’ aDepartment of Natural Sciences, Pusan National University of Technology, Pusan 608-739, South Korea b Department of Physics, Dongeui University, Pusan 614-714, South Korea ’ Department of Physics and Research Centerfor Dielectric and Advanced Matter Physics, Pusan National University?Pusan 608-735, South Korea Received 1 February 1995; revised 19 July 1995; accepted 24 July 1995
Abstract The characteristics of the second harmonic generation (SHG) in the Gdz( MoOq)g crystal grown by the Czochralski method were investigated at 1.064 pm light from an Nd : YAG laser. The phase matching angle, angular acceptance bandwidth and the temperature bandwidth were measured in type I phase matching. The nonlinear coefficient and SHG conversion efficiency were also obtained.
The Gd2( MOO,) 3 (GMO) crystal belongs to orthorhombic space group (point group mm2) and is a positive biaxial crystal [ 1,2]. The crystallophysical axes x, y, z of the GM0 crystal are parallel to the crystallographic axes b, a and c, respectively. It exhibits both ferroelectricity and ferroelasticity, and has potential applications in the electrooptical devices [3] and acoustic wave devices [ 41. Above the Curie temperature (T, = 159°C)) the unit cell becomes tetragonal with space group P42,m. ‘Many nonlinear optical crystals, such as NI-&H,PO, (ADP), KH,P04 (KDP), KTiOPO, (KTP), LiIO,, LiNbO,, LiB,O, (LBO), j?-BaB,O, (BBO) [ 51 have been studied extensively since the first generation of doubled frequency light by Franken et al. [ 61. KTP, LiIO,, LB0 and BBO have good second harmonic generation (SHG) characteristics, however, it is difficult to grow them and the LiIO, is hygroscopic [ 71. Among various nonlinear optical crystals, the GM0 crystal is * Corresponding
author.
0167-577x/95/$09.50 0 1995 Elsevier Science B.V. All rights reserved SSDIO167-577x(95)00180-8
relatively easy to grow. However, little attention has been paid to the GM0 crystal as a nonlinear optical crystal. There are a few reports on SHG of the GM0 crystal. Miller et al. [ 81 measured the nonlinear optical coefficients of the GM0 crystal using the Maker fringe method. Bonneville et al. [ 91 measured the linear and nonlinear optical coefficients to investigate the influence of the lanthanide ions on the nonlinear optical properties of the GM0 crystal. Borchardt et al. [lo] were the first researchers who introduced the GM0 crystal as the ferroelectric laser host and demonstrated the laser operation of the GM0 crystal. Bagdasarov et al. [ 111 proposed the possibility of a self-doubling laser with the GM0 crystal. In this Letter, we report the characteristics of critically phase-matched SHG of 1.064 pm light in the GM0 crystal grown by the Czochralski method. Angle tuning and temperature tuning curves of SHG at a fundamental wavelength of 1064 nm from a pulsed Nd : YAG laser were obtained in type I phase matching. The SHG conversion efficiency and effective non-
XI. Kim et al. /Materials
196
Fig. 1. Experimental
geometry
for the type I SHG.
linear coefficient of the GM0 crystal at a pulsed 1064 nm light were also measured and compared with wellknown nonlinear optical crystals. For the preparation of the GM0 crystal, Gd203 (99.9%, Aldrich, USA), MOO, (99.9%, Soegawa, Japan) and Pr601, (99.9%, Aldrich, USA) were mixed and ball-milled for 24 h and dried at 150°C for 24 h. They were calcined for 10 days at 780°C. The GM0 crystals were grown from this compound by the Czochralski method. The rotational speed of the seed was 48 rpm, and the pulling speed was 2.8 mm/h [ 121. The preferential growing direction was (110). A clear GM0 single crystal with a length of 50 mm and a diameter of 13 mm was obtained by this method. The prepared GM0 crystal was nonhygroscopic and transparent from 0.31 to 5.13 p,m. The fundamental beam for the SHG in the GM0 crystal was the 1.064 pm light from a pulsed Nd : YAG laser (SL804G, Spectron) with a pulse width of 6 ns. After generating doubled light through the GM0 crystal, the 532 run SHG light was separated from the fundamental light by a dispersive prism. A monochromator (1702, SPEX) and a PM tube (C3 1034, RCA) were employed to detect 532 nm light from the GM0 crystal. The detected signal was read out by a digital oscilloscope (9450A, LeCroy ) . In order to measure the SHG conversion efficiency of the GM0 crystal, a calorimeter (38-0101, Scientech) and a microvoltmeter ( 197, Keithley) were used. The transmission curve of the GM0 crystal was obtained using a spectrophotometer (Cary 5, Varian) and an FT-IR spectrophotometer (5020/5060, Galaxy ) . The transparent range of the GM0 crystal is 0.3 1 to 5.13 pm. The UV transparency of this crystal is comparable to KTP ( KTiOPO,, 0.35 pm) and is even better than that of LB0 (LiB,O,, 2.6 pm) in IR [ 51. Fig. 1 illustrates the experimental geometry for the type I SHG. The z-axis of the GM0 crystal is in the cut plane of the crystal and the x-axis is rotated about the z-axis by 43.5” from the cut plane. In order to measure
Letters 25 (1995) 195-198
the angular and temperature dependence, the GM0 crystal was mounted on a goniometer. The fundamental beam was directed at 8 and 4 to the z- and x-axes, respectively. The fundamental beam was polarized along the z-axis and the SHG light was polarized perpendicular to z-axis. Biaxial crystals such as KTP, LBO, GM0 have non-isotropic physical properties along the angle 4, therefore the phase matching angle for the angle 8 is different along the angle 4. Hobden [ 131 has shown that there are 13 topologically different patterns of phase matching loci in the condition of normal dispersion of biaxial crystals. The refractive indices of the GM0 crystal were measured by Bonneville et al. [ 91 1.8148,n1,= 1.861Oat l.O64pm, asnIx = 1.8144,n,,= and n2,= 1.8547, nZy= 1.8551, nzz= 1.914 at 532 nm. These data suggest that the type I phase matching (eeo interaction) is possible at 1.064 u,rn in the GM0 crystal. Therefore the eighth of Hobden’s patterns was observed in the situation where nzz > n,, > n2,,> n2, > nly>nlx, n,> (nl,+nl,)/Z nzy> (nl,+nJ/2. Fig. 2 shows the SHG intensity of the GM0 crystal as a function of external angle 8. The peak of the SHG intensity was achieved at 0,,, = 46.6”, &ext= 43.5”. The corresponding internal phase matching angle 8is 68.3”. This value is in good agreement with the angle 69.0” calculated from the refractive indices of the GM0 crystal [ 93. The SHG power is proportional to the function sin2(Ak1/2)l(AkZ/2)* [ 131, as the GM0 crystal of length 1 is deviated from the phase matchig angle. The phase mismatch Ak is given by
la2-
42
44
46
48
50
52
Q.,(ded Fig. 2. Second harmonic of external angle &,.
intensity of the GM0 crystal as a function
XI. Kim et al. /Materials Letters 25 (1995) 195-198
Fig. 3. Second harmonic of external angle A,,.
intensity of the GM0 crystal as a function
1.2 (I) 2 d 1.0 9 e 0.6 cd h 2
0.6
2 0, 0.4 2 E
0.2 0.0 20
40
60
60
100
120
For the exact phase matching, A k( $, To, qJ = 0 has to be satisfied. The angular acceptance can be obtained by finding the angle difference from the phase matching peak to the first zero. This angle difference is approximately equal to the full width at half-maximum (fwhm) of the the peak. Experimental data were fitted to the function, sin*( AkZ/2) / (Ak1/2)*, to measure the angular acceptance bandwidth. Angular acceptance bandwidth for the internal angle 19was obtained as A Ol= 1.2 mrad cm from fwhm by fitting. The angular acceptance bandwidth predicted from the indices of the GM0 crystal is A @= 1.5 mrad cm, and this is in good agreement with the experimental result. Fig. 3 shows the SHG intensity of the GM0 crystal as function of 8 around phase matching angle &, = 43.5” at &,, = 46.6”. Experimental data were fitted to the function, sin*( A kll2) I (Ak1/2)‘, to give the angular acceptance bandwidth of A +Z = 37.6 mrad cm for internal angle 4. Fig. 4 shows the SHG intensity of the GM0 crystal as a function of temperature T at external angle 8= 67.9”. The temperature acceptance bandwidth was measured as A Tl = 5.6”C cm. In general, A TZ is larger in the nonuniform material than in the uniform one [ 141. Therefore, this value can be used as a measure of the optical quality of the materials. In Table 1, the characteristics of the SHG in the GM0 crystal are summarized for comparison with those of some other nonlinear optical crystals.
Temperature(%) Fig. 4. Second harmonic of temperature.
197
intensity of the GM0 crystal as a function 2.5
0
Fundamental 50 I
d.,,=1.2f0.2
Ak=k,(~)
+k*(~)
-k3(20),
Power(mW) 100 I
pm/V
-
(1)
+WW 6T+ 8T
en,Tn, w,
a(Ak) &a a&J
a(Ak)
0.6
g
x
B
where k,(w) and k2( o) are the wave vectors of the fundamental wave, and k,(2w) is the wave vector of the second harmonic. The phase mismatch A k is a function of the sample temperature T, frequencies of the interacting waves and the angles. The dependence of A k on these parameters is given by
A& 0, T, w>= Ak(
150 1.0
- 0.6 .x 2 -0.4
;=; c
j+ae ..
s.
Fundamental
(2)
Intensity(MW/cm2)
Fig. 5. Second harmonic intensity of the GM0 crystal as a function of fundamental intensity.
XI. Kim et al. /Materials Letters 25 (1995) 195-198
198
Table 1 Comparison Crystal
KDP KTP BBO LB0 LiNbO, LiIO, GM0
of the characteristics Transparency
of SHG in the GM0 crystal and some other nonlinear crystals
(pm)
Temperature (“C cm)
0.2-1.5 0.3.5-4s 0.19-3.0 0.16-2.6 0.4-5 0.3-5.5 0.31-5.13
3.4 25 55 9 0.6 6.9 5.6
“Angular acceptance
bandwidth
range
for non-critical
phase-matching
Angular acceptance (mrad cm)
bandwidth
0.84 1.5 1.5 9 41” 0.32 3.4 (mrad cm”*).
Fig. 5 shows the SHG power and the conversion efficiency of the GM0 crystal as a function of fundamental intensity. The filled circle points in Fig. 5 were fitted to the conversion efficiency equation [ 151, 77= tanh’( Cdetiln3f21”21),
bandwidth
(3)
where I is the peak intensity of the fundamental beam, C= 27x( &eo) 1’4/h and h is the wavelength of the fundamental beam. The effective nonlinear coefficient of the GM0 crystal de,= 1.2 f 0.2 pm/V was obtained from this fitting. This value is about four times larger than the d36 of KDP, and five times smaller than the d,5 of KTP [ 51. The SHG conversion efficiency of a 1.4 mm thick GM0 crystal was about 0.76% at a fundamental intensity of 126 MW/cm2. In summary, we have grown the GM0 crystal by the Czochralski method and investigated the characteristics of type I SHG in the GM0 crystal at 1.064 pm. The phase matching angle was measured and coincided well with the calculated value. The angular acceptance bandwidths A 81, A 41 and the temperature bandwidth A TZwere obtained as 1.2 mrad cm, 37.6 mrad cm and 5.6”C cm, respectively. The effective nonlinear coefficient and SHG conversion efficiency of the GM0 crystal were de, = 1.2 + 0.2 pm/V and 0.76% at a fundamental intensity of 126 MW/cm2, respectively. Acknowledgements The present studies were supported by the Korean Science & Engineering Foundation (KOSEF) through
the Research Center for Dielectric and Advanced Matter Physics (RCDAMP) at Pusan National University.
References
[ 1 ] K. Nassau, H.J. Levinstein and G.M. Loiacono, J. Phys. Chem. Solids 26 (1965) 1805. [2] K. Aim, J. Phys. Japan 26 (1969) 387. [3] A. Kumada, Ferroelectrics 3 (1972) 115. [4] L.A. Coldren, R.A. Lemons, A.M. Glass and W.A. Banner, Appl. Phys. Letters 30 ( 1977) 506.
[ 51 V.G. Dmitriev, G.G. Gurzadyan
[ 61 [ 71 [8] [9]
and D.N. Nikosyan, eds., Handbook of nonlinear optical crystals (Springer, New York, 1991). P.A. Franken, A.E. Hill, C.W. Peters and G. Weinreich, Phys. Rev. Letters 7 (1961) 118. G. Nath and S. Haussuhl, Appl. Phys. Letters 14 ( 1969) 154. R.C. Miller, W.A. Nordland and K. Nassau, Ferroelectrics 2 (1971) 97. R. Bonneville and F. Auzel, J. Chem. Phys. 67 ( 1977) 4597.
[ 101 H.J. Borchardt andP.E. Bierstedt, Appl. Phys. Letters 8 ( 1966) 50.
[ 111 Kh. S. Bagdasarov,
G.A. Bogomolova, A.A. Kaminskii, A.M. Prokhorov and T.M. Prokhortseva, Soviet Phys-Doklady 16 (1971) 216. [ 121 S.C. Kim, J.D. Park, J.H. Kim, Y.S. Lyu and Y.J. Kim, Dongeui-non-jip 13 (1986) 53. [ 131 M.V. Hobden, J. Appl. Phys. 38 (1967) 4365. [ 141 R.A. Stolzenberger, Appl. Opt. 27 (1988) 3883. [ 151 Y.R. Shen, The principles of nonlinear optics (Wiley, York, 1984).
New