The X10468 series devices are a reflective type of pure phase Spatial Light Modulators (SLMs), based on Liquid Crystal on Silicon (LCOS) technology in which liquid crystal (LC) is controlled by a direct and accurate voltage, and can modulate a wavefront of light beam. The LCOS-SLMs are carefully designed to achieve high light utilization efficiency from various points of view, such as reflectivity, aperture ratio and diffraction noise due to the pixel structure.The X10468 series can be controlled via a PC using the Digital Video Interface (DVI), which is a standard interface for computer displays. The distortions in the LCOS chip, such as wavefront distortion and nonlinear response of the LC, are efficiently compensated by the contloller.Easy computer control, precise and linear phase modulation characteristics can be accomplished with the X10468 series. They can also provide high diffraction efficiency and high light utilization efficiency.
FEATURES ・Pure, linear and precise phase control ・High light utilization efficiency ・High diffraction efficiency ・Compact ・Ease of use (DVI compatible) ・Reflective type
The LCOS chip has a parallel-aligned nematic liquid crystal layer to modulate light. It only changes the phase of light without any change of intensity and rotation of polarization state. Phase modulation is changed according to the alignment of the LC. The LC alignment is controlled, pixel by pixel, using a CMOS backplane and a DVI signal via a PC.
X10468 Series
There are 8 standard types of the X10468 series available. The X10468-01/-07/-08 have no dielectric mirror but have higher diffraction efficiency and covers the wide wavelength range of the readout light spectrum. The X10468-02/-03/-04/-05/-06 have a dielectric mirror for a specified wavelength range. Figure 1 shows the spectral response for these types. An undesired interference noise will be appeared at the wavelength range from 700 nm to 900 nm for the X10468-07 and from 1150 nm to 1400nm for the X10468-08 owing to the reflection loss. The ultra violet light will cause a damage at the wavelength range less than 400 nm for the X10468-05. Please consult us the details.
Hamamatsu produces OEM devices that meet your requirements in the wavelength range from 355 nm to 1550 nm. We are
able to design and optimize device elements according to light wavelength used in your application.
Figure 1 : Spectral response of the X10468 series
Operating Characteristics
Light Utilization Efficiency
The X10468 series have high light utilization efficiency, which is defined a ratio of the 0th order diffraction light intensity to the input light intensity. The high light utilization efficiency mainly depends on reflectivity, and the amount of diffraction loss caused by the pixel structure. We adopted advanced CMOS technology to make diffraction loss smaller. As a result, the diffraction loss is less than 5 %. The X10468-2/-03/-04/-05 have a dielectric mirror which has high reflectivity. Therefore, these types have very high light utilization efficiency about 90 %. The X10468-01/-07/-08 have relatively low light utilization efficiency about 72 % compared to the ones with dielectric mirror but have wide spectral response characteristic.
Phase Modulation
Figure 2 : Phase Modulation
The X10468 series can achieve phase modulation of more than 2 radians over the 400-1100 nm readout wavelength range. The X10468 series comes pre-calibrated from the factory for a specified wavelength range to have more than 2 radians of phase modulation and its linear characteristics. Figure 2 shows typical phase modulation characteristics. A phase shift of 2 radians or more and a linear phase response are achieved. The phase modulation curves for 95 % pixels lies within +/- 2 .
Diffraction Efficiency
The X10468 series is a pure phase SLM with high precision phase control; therefore, it has high diffraction efficiency close to the theoretical values. Figure 3 shows images of diffracted spots, when a multi-level phase grating is formed in the X10468 and Figure 4 shows typical diffraction efficiency characteristics. Here, diffraction efficiency is defined I1/I0, I1 is intensity of the 1st order diffraction spot, I0 is the intensity of the 0th order light when no pattern is displayed.
Figure 3 : Diffracted spots images
Figure 4 : Diffraction efficiency
(a) No pattern
(b) 2-level grating (25 lp/mm)
(c) 4-level grating (12.5 lp/mm)
Output Images
The X10468 series has high precision phase control and high diffraction efficiency, and is very suitable for holographic applications. Figure 5 (a) is a interferometer picture of output wavefront with a flatness calibration. The image in Figure 5(b) was reconstructed as the 1st diffraction order of the kinoform through the Fourier transform optics. Figure 5(c) shows a clear Laguerre Gaussian (LG) beam of (0, 1) order.
(a) Interferogram of output
wavefront with calibration
Area: 800 x 600 pixels
RMS: 0.025 (=532 nm)
(b) Reconstructed image of CGH
(c) LG beam
Specifications
Parameter
X10468 series
Unit
-01
-02
-03
-04
-05
06
-07
-08
Input signal
Digital Video Interface ( DVI )
---
DVI signal format
SVGA ( 800 × 600 pixels )
---
DVI frame rate
60
Hz
Number of input levels
256 ( 8 bits)
levels
Effective area
16 12
mm
Maximum spatial resolution
25
lp/mm
Fill factor
95
%
Typical response resolution *1
Rise
10
(633 nm)
25
(785 nm)
30
(1064 nm)
15
(532 nm)
15
(405nm)
20
(633nm)
15
( 064nm)
30
( 550nm)
ms
Fall
35
(633 nm)
65
(785 nm)
80
(1064 nm)
30
(532 nm)
30
(405nm)
45
(633)
70
(1064nm)
140
(1550nm)
ms
Readout light wavelength
400 - 700
80050
105050
51050
41010
65050
620 to 1100
1000 to 1550
nm
Typical light utilization efficiency
76
(633 nm)
94
(785 nm)
95
(1064 nm)
87
(532 nm)
85
(405 nm)
90
(633 nm)
80
(1064 nm)
82 (1550 nm)
%
Input voltage (AC)
100 to 230 ( 50 Hz / 60 Hz )
V
Power consumption
50
VA
Weight (Head)
Approx. 450
g
Weight (Controller including cables)
Approx. 4100
g
*1 Time required to change from 10 % to 90 % for 2 modulation.
Figure 1 : Spectral response of the X10468 series
radians over the 400-1100 nm readout wavelength range. The X10468 series comes pre-calibrated from the factory for a specified wavelength range to have more than 2 
.
(
12
50
modulation.
