Spatial Light Modulator (SLM)

What is SLM?

• • An device that imposes some form of spatially-varying modulation on a beam of light.

It can modulates the intensity the phase simultaneously.

or phase of the beam or both the intensity and

Hamamatsu X10468 Series

• Liquid crystal on silicon (

LCOS

) chip based

Phase-Only Modulator

•

FEATURES

･ Pure, linear and precise phase control ･ ･ High light utilization efficiency High diffraction efficiency ･ ･ ･ Compact Ease of use(DVI compatible) Reflective type LCOS chip •

APPLICATIONS

･ Laser material processing ･ ･ Optical manipulation Wavefront correction ･ ･ Pulse shaping Optical testing Hamamatsu, X10468 series manual, 2009

Specifications

TEM00

A i



A

0 e

i

 0

How it works

Hologram

LG01

A o



T SLM



A i

LG01 Hologram   tan  1

y

 

Transmittance at SLM

T SLM



i

  1 By modulating the phase of incident light, the intensity of output light can be changed.

Phase Modulation Characteristic

• The X10468 series can achieve phase modulation of more than 2π radians over the 400-1100 nm readout wavelength range.

• The phase modulation curves for 95 % pixels lies within +/- 2 σ .

• • • •

Installation

Check that the PC and the LCOS-SLM controller are turn off.

Turn on the PC.

Change the display properties . Connect the second display. (LCOS-SLM) Change the properties of the second display as shown below.

Display size: 800 x 600 (SVGA) Refresh rate: 60 Hz Colors: True color (32 Bit) • • • Turn on the LCOS-SLM controller. All LEDs will illuminate temporarily.

Check that the error lamp in the LCOS-SLM controllers is not illuminated or flashing continuously . If the error lamp is illuminated or flashing continuously, the PC settings may be wrong, or the cables may not be properly connected.

When the power is turned on, the LCOS-SLM warms up for about 10 seconds, during the POWER LED flashes. You can start using the LCOS-SLM after that. The OUTPUT LED flashes for five minutes to indicate that the device is warming up; please refrain from using it during this time .

This procedure should be kept if the error lamp in the LCOS-SLM controllers is lit or flashing.

Display setting

• Set the resolution of 2 nd monitor to 800x600.

• The 2 nd monitor will be recognized as LCOS-SLM.

Display the hologram on SLM using C++

Retrieving monitor info.

• • •

EnumDisplayDevices

: retrieves information about one of the graphics modes for a display device

EnumDisplaySettings

: obtain information about the display devices(monitors) in the current session.

Include

“windows.h”

to use these functions Reference: Microsoft MSDN

EnumDisplayDevices

EnumDisplaySettings

Useful OpenCV GUI functions OpenCV

is a computer vision library originally developed by Intel . It is free for commercial and research use under the open source BSD l icense . The library is cross-platform , and runs on Windows , Mac OS X , Linux , PSP , VCRT (Real-Time OS on dded devices. It focuses mainly on Smart camera real-time ) and other embe image processing.

• • • • • • •

cvNamedWindow cvDestroyWindow cvMoveWindow cvShowImage cvLoadImage cvWaitKey cvReleaseImage

To use these functions, install OpenCV. Copy

“cxcore100.dll”

and C:\WINDOWS\system32.

“highgui100.dll”

located at C:\Program Files\OpenCV\bin in And include

“highgui.h”

and link and

“highgui.lib”

in the program

“cxcore.lib

Reference: Intel® Open Source Computer Vision Library

cvNamedWindow, cvDestroyWindow

cvMoveWindow, cvShowImage

cvLoadImage

cvWaitKey, cvReleaseImage

Sample code

Displayed on the SLM