1 of 24

Efficient calculation of computer generated holograms via parallel computing

Vincent Ricardo Daria1,2 and Andrew Banas1

1. Instrumentation Physics LaboratoryNational Institute of PhysicsUniversity of the PhilippinesDiliman, Quezon City

2. Computational Science Research CenterUniversity of the Philippines Diliman, Quezon City

2 of 24

Holograms: Tailored optical landscapes

Output 3D light fields

LaserOpticssystem of

lenses

Spatial light modulator

Com puter

Hologram

3 of 24

Spatial Light Modulator: a promising tool for dynamic beam control

Digital technology: Computer-addressable

pixel array

Amplitude modulationPhase modulation

http://www.avdeals.comhttp://www.holoeye.com

4 of 24

High-optical throughput tailored optical landscapes

Generalized Phase Contrast

Holographic

5 of 24

Tailored beam shapes via the Holographic method(Gabor, 1948)

Output intensity patternHologram (Records Complex Field)

SignalBeam

ReferenceBeamCom puter

6 of 24

I.F.T.

Intensity constraints

F.T.Intensity

constraints

Phase

Iterative hologram design: Gerchberg-Saxton Algorithm

R.W. Gerchberg, W.O. Saxton, Optik 35, 237 (1972)

Hologram Hologram planeplane

Fourier Fourier planeplane

7 of 24

Parallel Fast Fourier transform

t = 3.85x -0.8133

t = 0.96x -0.9737

0.01

0.1

1

10

0 2 4 6 8 10 12 14 16

Number of nodes, x

Tim

e (

se

co

nd

s)

Athlon Cluster (750 MHz)

Intel Pentium 4 Cluster (2.3 GHz)

Banas and Daria, Proc. Of SPP (2005)

Test cluster

8 of 24

Parallel Gerchberg-Saxton Algorithm

A Banas, A Hilario and V Daria, Proc of SPP 2006

9 of 24

Interface with experimental setup

Spatial light

modulator

Camera

Fast Ethernet100 MBps

10 of 24

The CSRC –High Performance Computing Facility

Nodes: (32)•Intel Pentium 4 3.2 GHz•Gigabit Ethernet

• Servers (4)•Dual processor•Intel Xeon 2.8 GHz (32-bit)•Gigabit Ethernet

11 of 24

Parallel Gerchberg-Saxton algorithm performance with the CSRC HPC

0.1

1

10

100

0 2 4 6 8 10 12 14 16 18 20

Nodes

Ru

n T

ime

(s)

2048 X 2048

1024 X 1024

512 X 512

256 X 256

128X 128

Numerical field reconstruction

Network traffic

12 of 24

Results

TargetNumerical

reconstructionOptical

reconstruction

13 of 24

Summary for Parallel GS algorithm

Developed a parallel Gerchberg-Saxton algorithm for deriving computer generated holograms (CGH).

Large CGH arrays are distributed into computing nodes thereby easing memory allocations for each node

Significant increase in speed of calculation is achieved at larger arrays

14 of 24

Wavefront engineering group

Team Leader Vincent Ricardo Daria, DrEng (Associate Professor)

ResearchersDarwin Palima, PhD (Adjunct Professor)Anthony Montecillo (Research Associate)Godofredo Bautista (PhD Physics student)Jacquiline Romero (MS Physics student)Andrew Banas (BS Physics student)Atchong Hilario (BS Applied Physics student)Reniel Cabral (BS Applied Physics student)

15 of 24

Thank you

Vincent Ricardo DariaNational Institute of PhysicsCollege of ScienceUniversity of the PhilippinesDiliman, Quezon City E-mail: vdaria@nip.upd.edu.ph