www.iap.uni-jena.de

Optical Design with Zemax

for PhD - Basics

Lecture 3: Properties of optical systems II

2013-05-30

Herbert Gross

Summer term 2013

2

Preliminary Schedule

No Date Subject Detailed content

1 02.05. Introduction

Zemax interface, menus, file handling, system description, editors,

preferences, updates, system reports, coordinate systems, aperture, field,

wavelength, glass catalogs, layouts, raytrace, system insertion, scaling,

component reversal

2 16.05. Fundamentals Diameters, stop and pupil,pick ups, solves, variables, ray fans, quick focus,

3D geometry, ideal lenses, vignetting, footprints, afocal systems,

3 23.05. Properties of optical systems I Aspheres, gratings and diffractive surfaces, special types of surfaces,

telecentricity

4 30.05. Properties of optical systems II Ray aiming, Delano diagram, lens catalogs

5 06.06. Aberrations I Representations, geometrical aberrations, spot, Seidel, transverse aberration

curves, Zernike wave aberrations

6 13.06. Aberrations II PSF, MTF, ESF

7 20.06. Imaging Fourier imaging, geometrical images

8 27.06. Advanced handling I Slider, universal plot, I/O of data, multi configurations

9 04.07. Optimization Algorithms, merit function, methodology, correction process, examples

10 11.07. Correction I Principles, simple systems

1. Ray aiming

2. Delano diagram

3. Lens catalogs

4. Afocal and telecentric systems

5. Slider and universal plots

3

Contents

Userdefined diameter at a surface in

the Lens Data Editor (U)

- serves also as drawing size in the

layout (for nice layouts)

- if the diameter of the system stop is fixed, the initial aperture can be computed automatically by

General / Aperture Type /

Float by Stop Size

This corresponds to a ray aiming on the rim of the stop surface. The aperture values in the PRESCRIPTION DATA list then changes with the diameter

A more general aiming and determination of the opening for all predefined diameters is not possible in Zemax

4

Ray Aiming

Delano Diagram

Special representation of ray bundles in

optical systems:

marginal ray height

vs.

chief ray height

Delano digram gives useful insight into

system layout

Every z-position in the system corresponds

to a point on the line of the diagram

Interpretation needs experience

CRyy

lens

y

field lens collimatormarginal ray

chief ray

y

y

y

lens at

pupil

position

field lens

in the focal

plane

collimator

lens

MRyy

Pupil locations:

intersection points with y-axis

Field planes/object/image:

intersectioin points with y-bar axis

Construction of focal points by

parallel lines to initial and final line

through origin

y

y

object

plane

lens

image

plane

stop and

entrance pupil

exit pupil

y

y

object

space

image

space

front focal

point Frear focal

point F'

Delano Diagram

Delano Diagram

Influence of lenses:

diagram line bended

Location of principal planes

y

y

strong positive

refractive power

weak positive

refractive power

weak negative

refractive power

y

y

object space image space

principal

plane

yP

yP

Delano Diagram

Afocal Kepler-type telescope

Effect of a field lens

y

y

lens 1

objective

lens 2

eyepiece

intermediate

focal point

y

y

lens 1

objective

lens 2

eyepiece

field lensintermediate

focal point

Delano Diagram

Microscopic system

y

y

eyepiece

microscope

objective tube lens

object

image at infinity

aperture

stop

intermediate

image

exit pupil

telecentric

Conjugated point are located on a

straight line through the origin

Distance of a system point from

origin gives the systems half

diameter

Delano Diagram

y

y

object

space image

space

conjugate

line

conjugate line

with m = 1

principal point

conjugate

points

y

y

maximum height of

the coma ray at

lens 2

curve of

the system

lens 1lens 2

lens 3

D/2

10

Location of principal planes in the Delano diagram

Triplet Effect of stop shift

Delano Diagram

y

y

object

plane

lens L1

lens L2

lens L3

image

plane

stop shift

y

y

object

spaceimage

space

principal plane

yP

yP

Kepler telescope with field lens

Microscopic illumination

Delano Diagram

y

y

lens 1

objective

lens 2

eyepiece

field lens

intermediate

image

y

source

field

stop

aperture

stopcondenser

collector

Tele system Galilean telescope

Retro focus objective

Delano Diagram

y

y

negative

lens

positive

lens

pupil

image

y

y

negative

lens

positive

lens

pupil

image

Vignetting :

ray heigth from axis

Marginal and chief ray considered

Line parallel to -45° maximum diameter

yya

Delano Diagram

object

pupil

chief ray

marginal ray

coma ray

yyy + y

y

y

maximum height at

lens 2

system polygon line

lens 1

lens 2

lens 3

D/2

Vignettierung :

Delano Diagram

y

y

line of the Delano

diagram

aperture

bundle

y

yradius free of

vignetting

D/2 = 2 y + y

position of the

system surface

maximum height of

the coma ray

MR

CR

Delanos y-ybar diagram

Simple implementation in Zemax

16

Delano Diagram in Zemax

Example:

- Lithographic projection lens

- the bulges can be seen by characteristic arcs

- telecentricity: vertical lines

- diameter variation

- pupil location

17

Delano Diagram in Zemax

telecentric

image

telecentric

object

pupil

largest beam

diameter: surface 19

Dmax/2

1

23456

78

910

11

12

13

1415

16171819

2021

22

2324

2526

27

28

29

3031

32333435

3637

3839

40

41

42

430

smallest

beam

diameter:

surface 25

yMR

yCR

negative

lenses

positive

lenses

Lens catalogs:

Data of commercial lens vendors

Searching machine for one vendor

Componenets can be loaded or inserted

Preview and data prescription possible

Special code of components in brackets

according to search criteria

18

Lens Catalogs

Some system with more than one lens available

Sometimes:

- aspherical constants wrong

- hidden data with diameters, wavelengths,...

- problems with old glasses

Data stored in binary .ZMF format

Search over all catalogs not possible

Catalogs changes dynamically with every release

Private catalog can be generated

19

Lens Catalogs

Image in infinity:

- collimated exit ray bundle

- realized in binoculars

Object in infinity

- input ray bundle collimated

- realized in telescopes

- aperture defined by diameter

not by angle

object at

infinity

image in

focal

plane

lens acts as

aperture stop

collimated

entrance bundle

image at

infinity

stop

image

eye lens

field lens

Object or field at infinity

Angle Aberrations

Angle aberrations for a ray bundle:

deviation of every ray from common direction of the collimated ray bundle

Representation as a conventional spot diagram

Quantitative spreading of the collimated

bundle in mrad / °

perfect

collimated

real angle

spectrum

real beamDu

z

Special stop positions:

1. stop in back focal plane: object sided telecentricity

2. stop in front focal plane: image sided telecentricity

3. stop in intermediate focal plane: both-sided telecentricity

Telecentricity:

1. pupil in infinity

2. chief ray parallel to the optical axis

Telecentricity

telecentric

stopobject imageobject sides chief rays

parallel to the optical axis

22

Double telecentric system: stop in intermediate focus

Realization in lithographic projection systems

Telecentricity

telecentric

stopobject imagelens f1 lens f2

f1

f1

f2

f2

23

Special Cases of Wave Aberrations

3. afocal system

- exit pupil in infinity

- plane wave as reference

4. telecentric system

chief ray parallel to axis

24

yp

z

reference

plane

wave front

image in

infinity

yp

z

y'

reference

sphere

wave front

pupil

planeideal

image

plane

axial

chromatic

1.Telecentric object space

Set in menue General / Aperture

Means entrance pupil in infinity

Chief ray is forced to by parallel to axis

Fixation of stop position is obsolete

Object distance must be finite

Field cannot be given as angle

2.Infinity distant object

Aperture cannot be NA

Object size cannot be height

Cannot be combined with telecentricity

3.Afocal image location

Set in menue General / Aperture

Aberrations are considered in the angle domain

Allows for a plane wave reference

Spot automatically scaled in mrad

25

Telecentricity, Infinity Object and Afocal Image

Slider option in menue: Tools / Miscellaneous / Slider

Dependence of chosen window output as a function of a varying parameter

Automatic scan or manual adjustment possible

Example 1: spot for changing the aspherical constant of 4th order of a lens

Example 2: Optical compensated zoom system

26

Slider

Possibility to generate individual plots for special properties during changing one or two

parameters

Usually the criteria of the merit function are shown

Demonstration: aspherical lens, change of Strehl ratio with values of constants

The sensitivity of the correction can be estimated

It is seen, that the aspherical constants on one side are enough to

correct the system

27

Universal Plot

One-dimensional: change of 4th

order coefficient at first surface

Two-dimensional case: dependence on

the coefficients on both sides

28

Universal Plot

Universal plot configurations can be saved and called later

Useful example: spot diameter as a function of a variable: operator RSCH

29

Universal Plot