Student : Chen – Fung Tsen Advisor : Sheng – Lung Huang 1

Outline System Overview Sample Arm Optics -- Human/Rat eye model -- ZEMAX simulation Dispersion Compensation --Numerical dispersion compensation Plan and Schedule 2

System Overview 3 FC 50:50 VHG Dispersion compensation Sample arm optics

Our system Light source : SLD(Corning HI780 ; FC/APC) Patched fiber : HI1060 ; APC/PC *Fiber isolator Fiber coupler : Nufern 630-HP ; 50 : 50 Fiber polarization controller (sample arm) : FPC560 Collimated lens: Aspherical lens (focal length=8mm ; N.A=0.5 ; Power=20 x) Focusing lens : Scan lens(LSM02-BB - EFL=18 mm) Spectrometer: VHG: 1200 line/mm Achromatic lens : Thorlabs f=8cm CCD : e2V 4096 pixels ; System performance : Axial resolution : 9.6μm 4

Sample arm optics --Rat/ Human eye model Human eye model 5

Rat eye model –Gradient Index Schematic Lens 6 * Crystalline lens data r : Distance of Ray Crossing from Lens Vertex (mm) Axial lengthNAfRetina thicknessPupil size Human24mm mm130μm~370μm6mm Rat6.29mm mm230μm2mm

Sample Arm Optics – simulated by ZEMAX 7 Collimated light

ZEMAX simulation Diffraction-limited performance: Theoretical spot sizes on the retina calculated with ZEMAX using standard eye models. Spot size 越小越好 =>> properly select objective lens/eyepiece 8 Ex:

Ex. “Measurement of pulsatile total blood flow in the human and rat retina with ultrahigh speed spectral/Fourier domain OCT ”— For rat : Scan lens : focal length = 50mm ; objective lens f = 12.5mm For human : Scan lens : focal length = 80mm ; objective lens f = 30mm Theoretical spot sizes on the retina calculated with ZEMAX using standard eye models were ~15μm for rat and ~20μm for the human. CCD的擷取資料頻率最高30kHz左右。CCD訊號與掃 描鏡掃描頻率呈現倍數關係。此倍數是斷層掃描的線 數。 設定每條A-line的橫向解析度 ~spot size on retina 的 一半=> 以此決定掃描鏡頻率 9

Numerical dispersion compensation 10 “High-speed, high-resolution Fourier-domain optical coherence tomography system for retinal imaging in the 1060 nm wavelength region” Optics Letters,2004

Plan and Schedule ZEMAX simulation for sample arm optics=> suitable scan lens, eyepiece (next week) Complete the system- insert isolator, scan lens, scan lens compensator.(July) Image acquisition and signal processing(July) Contact with Dr. Yang for further research 11